USER'S GUIDE and INTEGRATION GUIDELINES - Ham
Contents
1. 2 2 MAX 40 CONTACT EXTRACTION FORCE 3 ez 0 9 TYP 508013352005 2 oz 0 8 MIN 50 0 2904 60 46 900122 86 MEASURED WITH 025 0 64 50 PIN RECOMMENDED WIRE SIZE 28 AWG STRANDED 50 AWG SOLID G 50 3 180 80 72 2 900 73 66 1 100 27 3 RECOMMENDED MATING PIN SIZE 025 0 64 SQUARE OR ROUND N T ELECTRICAL OTE 1 POLARIZING TABS ARE OPTIONAL SEE ORDERING NOMENCLATURE 2 STRAIN RELIEF 15 AVAILABLE SEPARATELY CURRENT RATING 1 AMP VOLTAGE RATING 500 Vrms DIELECTRIC WITHSTANDING VOLTAGE 800 Vrms MIN INSULATION RESISTANCE gt 1000 Megohms CABLE ACCESSORIES CONTACT RESISTANCE IO Millionms TYP T S 25 Milliohms MAX i MEASURED THROUGH INSULATION DISPLACEMENT PORTION ANO MATING PIN MATING CA PRODUCT us HE AND DUAL ROW STRIP HEADERS ca CJ LLEI NUMBER IU RELIEF CONTACT BLANK NO STRAIN RELIEF POSITIONS SR WITH STRAIN RELIEF POLARIZING TABS BLANK NONE ON 10 THRU 80 POSITIONS INSULATION SPT SINGLE POLARIZING ON i 10 THRU 60 POSITIONS DISPLACEMENT OPT DUAL POLARIZING TABS ON SOCKET 50 AND 60 POSITIONS ONLY 000010 00025 GOLD OVER 000075 00190 NICKEL 000250 00635 TIN OVER 000075 00190 NICKEL CIRCUIT ASSEMBLY CORP THOMAS ST IRVINE CALIF 92718 2703 PHONE 714 855 7887 TELEX 83109 UO LPRO Us2. 29 Cats nonocTm j o0shi wirkEL TIE onarB 2900 Pia THOT SOCKET Xx ABLE accsREAMIER 10 THEW POSIT Ew ION DISPLACEMENT 4150 JEF CLIEF We 03 28 2000 INSULATION OIL PLACEMENT SOCKET 100 X I00 STRAIN RELIEF DUAL LEAF SIDE MPE CONTACT CONTACT 1 INDICATOR CONTACT PONT MAX INSERTION DEPTH A EQ risp die 400 POLARIZING 5 SEE NOTE 1 FEATURES TABULATION CONFORMS TO MIL C 83503 7C 2 PIN WIRE 1 CONSTRUCTION Waa OE a B m d QUAL LEAF SIDE WIPE CONTACT SOSITIONS STRAIN RELIEF PULL TABS AND CABLE ARE AVAILABLE in IN MM IN MM SEE CABLE AND ACCESSORIES SECTION SPECIFICATIONS t o 6a0 17 27 00 10181 ENVIRONMENTAL i4 22 35 500 15 24 TEMPERATURE RANGE 55 C TO 125 C 16 124 TUBE 17 78 L MECHANICAL 20 1 180529 97 22 86 1 INSULATOR MATERIAL GLASS FILLED POLYESTER GRAY UL94V O 7 IT CONTACT MATERIALE PHOSPHOR BRONZE z5 37 55 200 30 48 ai CONTACT INSERTION FORCE 4 1 1 N 34 1 880 47 75 1 600 40 84
3. Once the LPRO is plugged in and is receiving power wait 3 to 4 minutes while the unit achieves atomic lock During this period the monitored BITE signal should be HIGH 4 2 Vdc to 4 8 Vdc Once the unit achieves atomic lock the BITE signal goes LOW 50mV with respect to GND At this point the output frequency should be approximately 5 8 of absolute frequency Thirty minutes after applying power to the LPRO the rf output frequency will be very close to full accuracy refer to LPRO specifications or Reference 1 for information about accuracy versus time from turn on NOTE the output frequency of the LPRO is more accurate than most counters See Reference 2 for a discussion of methods that allow the verification of atomic frequency standards similar to the LPRO Appropriate measurement equipment can be obtained from EFRATOM Ask EFRATOM Marketing or your local sales representative about the FMS 200 and FMS 201 product line 2 4 Frequency Adjustment Procedure There are two primary reasons to adjust the external frequency output of the LPRO The first is to compensate for aging over time and the second is to syntonize the rubidium oscillator to a more accurate primary frequency source The LPRO is considered to be a secondary frequency standard 1 much more accurate than a quartz frequency standard but not as accurate as a cesium standard which is considered to be a primary standard By syntonizing the LPRO s rubidium oscill
4. o3auF 39uF 033uF AUF SMBYW 02 0805 1812 0805 1206 2103 24V RTN 8 e 39 OMH 982 1 J1 1667 1000PF ok EXT C FIELD gt 14 6V INPUT e J 6105 12 R214 R217 1000PF 033yF 14 LAMPV FIF 13 VV VW 5 m 10K 10K H7 17V E THKF THKF R118 LMC6484 0805 L 0805 332K HA 55 C 212 77 1 1 8w 51 1K 033uF 1671 805 R 135 R119 145 EE Me 033uF 562K y 14 6V R MAGNETIC coarse FIELD 5 gt CONTROL 6 R FINE R124 C FIELD R117 121 5K 100K LMC6482 51K GAIN 033 f eo ED cw C122 LE C FIELD iG ADJUST 01 Figure 3 1 Interface Circuity of LPRO Connector J1 06 09 2000 LPRO User s Guide amp Integration Guidelines 5 0 102502 16 LPRO Design Integration Considerations 3 4 ELECTRICAL INTERFACE 3 4 1 LPRO rf Output 3 4 1 1 Conversion of 10 MHz sine to 10 MHz TTL The LPRO was designed for a 10 MHz sine output with a 50 ohm source impedance at 10 MHz and for a 50 ohm load The sine output permits built in ESD and EMI protection even for the rf output signal the filter plate capacitance for the rf output signal is built into the matching circuit The connector scheme is designed for direct plug in of the LPRO J1 filter plate connector into the customer s circuit board connector saving the cost of a cable harness Transmitting rf output signals over long distances is less of an EMI issue for the user when the signal is a sine w
5. Locking Clip Contacts Wire Crimp Contacts with Insulation Support Material Contact Body Phosphor bronze Contact Spring Stainless steel Related Product Data Housings Used With pages 3176 amp 3177 Application Tooling page 3221 Technical Documents page 3223 Plating Specifications Sel Goid Nickel Gold flash over 000050 nickel on entire contact with additional 000030 goid on contact area Br Tin Lead Nickel 000100 000200 bright tin lead over 000050 nickel on entire contact AMP INCORPORATED HARRISBURG 17105 PHONE 717 564 0100 TWX 10 657 4110 PRODUCT INFORMATION CENTER PHONE 1 800 522 6752 LPRO User s Guide amp Integration Guidelines S 0 102502D Specifications subject to change Dimensioning Dimensions are in inches For latest design specifications 1 800 522 6752 Quick Change Wire Sue Ins Dia A Platin Part Numbers Applieator for Hand Range Dim 8 AMP 0 LECTRIC Tool AW Strip Form Loose Form Machine Sel Gold Nickel 87190 1 87191 1 30 98 029 039 550 Lu 719052 ana 687792 2 90295 1 25 Set Gold Nickel 87124 1 87165 85 2 038 X 466721 2 90289 26 22 098062 584 ener Tin Nickel 87124 2 871652 eid pee Sel Gold Nickel 867052 2 038 584 4 2 m 20 038 062 Br Tin Nickel 867052 1 667212 Notes 1 These contacts must be crimped in accordance with AMP Specitication No 114 25006 in order to f
6. BITE OUTPUT EXT C FIELD VOLTAGE ADJ 24V RTN CRYSTAL VOLTS MONITOR POWER 24V 470 pF PI FILTER SHORTING PIN 470 pF PI FILTER SHORTING PIN 1000 pF PI FILTER 1000 pF PI FILTER 1000 pF PI FILTER 1000 pF PI FILTER 1000 pF PI FILTER 1000 pF PI FILTER Built In Test Equipment unlock indicator TABLE 1b Mating Connector Options Mfg Part No No Positions 87133 2 shell only 10 CA 10 IDS T 10 CA 10 IDS2 T 10 622 1000 10 BCS 15 L D HE 10 BCS 15 L D DE 10 Mfg AMP requires 10 piece 87165 2 connector insert Circuit Assy Corp Circuit Assy Corp Thomas amp Betts SAMTEC right angle entry SAMTEC straight in entry This information subject to change without notice NOTE Refer to Appendix A for the listed connector manufacturer s specification sheets LPRO User s Guide amp Integration Guidelines 2 5 0 1025020 06 09 2000 12 LPRO Specifications Electrical Specifications Unless otherwise indicated 24V input 25 C Output Frequency Waveform 10 MHz sine wave Output Level 55 Vrms 05 Vrms into 50 Q 7 8 0 8 dBm NOTE refer to LPRO datasheet for additional details on electrical specifications Environmental Specifications Operating Temperature 30 C baseplate to 70 C BP Temperature Coefficient refer to LPRO data sheet Storage Temperature 55 C to 85 Altitude Operating 200 ft to 40 000 ft lt 1E 13 mbar N
7. Figure 3 6 rf Output Impedance Versus Prequeticy ode Bes ele testo so erie eee 24 Figure 3 7 rf Output Impedance Versus Frequency iu o eerte ge cope co lee 24 Figure A 1 Suggested Mating to Circuit Card Assembly esee 33 LIST OF TABLES Table Tas JT Connector Interfate iui uie o ac eie tene adero quatn ieee eee 2 Table 1b Mating Connector Options eed Sos rte a redi oe Sek ee ike dide ade as 2 Table 3 1 Phase Noise Sine to TTL 18 iii References 1 NIST Technical Note 1337 Characterization of Clocks and Oscillators Sullivan Allan Howe Walls Editors March 1990 3 Frequency Stability Fundamentals and Measurement V Droupa Editor IEEE Press 1983 4 General Considerations in the Metrology of the Environmental Sensitivities of Standard Frequency Generators EEE Frequency Control Symposium 1992 pp 816 830 5 NIST Technical Note 1297 Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results 1994 Edition B Taylor and Kuyalt 6 Use of Statistics for Specifying Commercial Atomic Frequency Standards DeWatts etal 1996 Frequency Control Symposium Section 1 introduction 1 0 Description The Model LPRO is partof DATUM s family of precision frequency generator components The LPRO is designed for low cost mass production It is
8. MTBF hrs 381 000 351 000 320 000 253 000 189 000 134 000 RELEX software V5 1 part stress 1 case 3 Physical Specifications Weight 1 05 Ibs max Size 3 7 X 5 0 X 1 5 H Warranty 2 years Extended Warranty Consult factory NOTE Contact DATUM Irvine for application support LPRO User s Guide amp Integration Guidelines 4 06 09 2000 5 0 1025020 LPRO Rubidum Oscillator 20 o lt 32 VI z 15 o lt a 24 VI on a c 18 V 10 5 20 10 0 10 20 30 40 50 60 70 80 1236 BASEPLATE TEMPERATURE Figure 1 3 Total Unit Power Dissipation Typical free convection S R H E 10 30 20 10 0 10 20 30 40 50 60 TU 80 BASEPLATE TEMPERATURE Baseplate Temperature deg C Figure 1 4 Representative LPRO Af f versus Temperature Figure 1 4 illustrates the Tempco performance of nineteen LPRO units as measured across the given temperature range LPRO User s Guide amp Integration Guidelines 5 06 09 2000 5 0 102502 Section 2 installation amp Operation 2 1 Theory of Operation The Model LPRO makes use of the atomic resonance property of rubidium to control the frequency of an unheated quartz crystal oscillator via a frequency locked loop FLL The FLL function block is shown in Figure 2 1 A microwave signal is derived from a 20 MHz voltage controlled crystal oscilla
9. One of the key specifications for an atomic frequency standard is the temperature coefficient The LPRO is designed for a low temperature coefficient without the need for temperature correction However in applications where the user requires a tighter temperature coefficient a common practice is to monitor the baseplate temperature of the LPRO and apply a correction signal via the External C field Adjust pin 7 on connector J1 This method can be successfully used for moderate correction for example to bring the maximum frequency change over the full operating temperature range to less than 1E 10 Applying more correction is possible but there are limits without issues for both yield loss and the test time required for correction as one runs into the inherent problems of subtracting two large numbers to accurately and consistently obtain a small difference Compensation using this scheme is suitable only for steady state conditions This is because of inherent mismatches between the thermal time constants of the mechanisms that cause tempera ture coefficient errors and because of the thermal time constant of the monitoring circuitry Tran sients from time constant mismatches will show up these transients are minimized if temperature ramp rates are limited Changing less than 2 C minute baseplate temperature should result in negligible transients from mismatches There are issues with changing the C field current in atomic frequency standar
10. 1 2 rf Output Impedance versus Frequency Figures 3 6 and 3 7 show the active rf output impedance for LPRO It shows a nominal 50 ohms at 10 MHz but a widely varying impedance at other frequencies This would have to be taken into consideration by the user if running the LPRO rf output into a non buffered filter 5 0V 35mA SINE 10K OSCILLATOR if 100 pF 10 MHz 10K 100pF 10 5K 1676 Figure 3 5 Sine to TTL Conversion Circuit Using a High Speed Comparator LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 19 LPRO Design Integration Considerations 3 4 1 2 rf Output Impedance versus Frequency Figures 3 6 and 3 7 show the active rf output impedance for LPRO It shows a nominal 50 ohms at 10 MHz but a widely varying impedance at other frequencies This would have to be taken into consideration by the user if running the LPRO rf output into a non buffered filter A Z B 0 0 MKR 10 900 000 Hz A 450 Q MAG 55 2253 Q 180 0 deg PHASE 22 6539 deg 180 500 Z 00 180 1692 A DIV 50 00 Q START 1 000 000Hz B MIN 180 00 deg STOP 100 000 000 000Hz MANUAL Figure 3 6 rf Output Impedance Versus Frequency A Z B O 0 10 000 000 000 Hz A 450 0 Q MAG 55 3277 Q p BMAX 180 0 deg PHASE 22 5747 deg 00 180
11. 38 1 1 500 POLARIZED SOCKET CONNECTOR zl A 5 020 Ordering Information CATALOG NUMBERS SOCKET CONN POLARIZED SOCKET CONN WITH WITH 08 1212477 gt 52100 622 1000 6221090 10 12 25 411 000 1210500 7 622 0000 POLARIZING KEY FOR POLARIZING CONNECTORS BY BLOCKING CONTACT ENTRY 1 00 039 DIMENSIONS IN MM INCHES T POLARIZED SOCKET STRAIN RELIEF A B 622 0441 04 958 377 2 54 100 1 90 075 3 20 128 5 08 200 10 16 400 12 70 500 622 1041 1720 577 622 1241 19 74 C777 622 1400 622 1401 822 1440 622 1441 2228 877 15 24 800 3 80 150 eure 4 E 190 075 622 2400 _ 622 2401 822 2430 822 2441 34 96 1 377 27 94 1 100 3 80 150 622 2000 622 2001 622 2030 622 2041 29 90 1 177 22 86 900 3 80 150 622 1600 622 1601 622 1630 622 1641 2482 877 17 78 700 3 80 150 622 2600 622 2601 822 2630 822 2641 31 52 1 477 30 48 1 200 3 80 150 622 3000 622 3001 622 3030 622 3041 42 80 1 677 1 35 56 1 400 3 80 150 522 3400 522 3401 522 3430 522 3800 822 3601 622 3630 622 3841 622 4030 47 68 1 877 9022 1 977 55 30 2 177 40 64 1 600 43 18 1 700 48 26 1 900 3 80 150 3 80 150 3 80 150 LL 822 4400 622 5001 622 6000 6226001 6226030 _ 6226041 60 8070 17 73 66 2 900 3
12. because of the lower drive impedances higher emissions from the faster waveform edges If EMI emissions are an issue a slower logic family may be in order The use of a small series resistor from the output of the gate to the load can reduce emission problems Good local power bypassing is recommended for this appli cation such as a small series resistor and a low ESR tantalum supply bypass capacitor 3 4 1 1 2 ECL TTL Level Shifter Figure 3 4 shows a sine to TTL converter using a positive ECL to TTL converter microcircuit The advantage to this approach is the lack of supply and ground noise Disadvantages are higher phase noise and cost compared to the ac couple CMOS approach and the extra power dissipation roughly 18 23 milliamperes more at 5V LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 17 LPRO Design Integration Considerations Table 3 1 Measured Phase Noise Sine to TTL Circuits Figure 1 Hz 10 kHz 100 kHz Test dBc Hz dBc Hz dBc Hz dBc Hz dBc Hz dBc Hz Notes 3 2 99 159 161 2 74 04 2 3 3 159 74 04 3 4 135 2 2 MCIOELT21D 3 5 98 118 118 119 119 120 2 4 LT1016 TYP LPRO 86 138 152 156 158 3 FRK LN 10 130 149 158 160 161 1 The Wenzel oscillator was used as a reference source for the phase noise test set 2 The FRK LN oscillator was used as a driving source for the sine to TTL circuit This oscillator was screened for best phase noise 3 Tes
13. housings m Standard contact box size 060 x 068 1 52 x 1 73 W Mini contact box size 060 1 52 sq B Mini Tandem Spring Housings be stacked on 100 2 54 centers in either direction m Mini Tandem Spring Housings are Recognized under the Camponent Program of Underwriters Laboratories Inc File No 28476 AMP Tandem Spring Receptacle Contacts are designed to mate with 025 0 64 square posts When used individually they will mate with posts as short as 125 3 18 and when used housing they will mate with 140 3 55 long posts These versatile contacts may be used for interconnecting posted pc panels wiring and cross connecting pin arrays The receptacle contact s box configuration provides long contact life with controlled contact mating forces which LPRO User s Guide amp Integration Guidelines 26 S 0 102502D minimize wear An external retention spring facilitates quick assembly and assures firm seating ih a contact housing Standard Tandem Spring Receptacle Contacts may be used for ganged connections in AMPMODU Mod IV closed entry housings having single or d uble row configurations centerline spacing as close as 100 2 54 Contacts also can be used in single row AMPMODU MTE housings or can be used as replacement contacts Mini Tandem Spring Receptacle Contacts are used in single or double row housings with 100 2 54 centerline
14. of the spurs will vary largely with the motor s speed and load conditions The Rb atomic frequency source uses a modulation demodulation lock in amplifier scheme with a modulation frequency of 152 Hz Inherent in this approach is sensitivity to noise at multiples of the modulation frequency This noise is coupled through both the heater and electronic power lines to cause modulation spurs on the output frequency Care should be taken to avoid the modula tion frequency and its lower harmonics roughly up to the tenth harmonic The LPRO has an internal linear regulator supplying power to the critical electronics includ ing the crystal oscillator which is the source for the 10 MHz output This regulator loses its ripple rejection attributes at frequencies greater than 100 kHz The crystal oscillator in the unit has some filtering to minimize the conductive spurs from affecting the oscillator It remains critical that a clean input supply is used if spur and phase noise performance is critical for the end user application This topic is discussed further in the LPRO Data Manual LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 23 LPRO Design Integration Considerations 3 9 LPRO Maintenance 3 9 1 LPRO Design Goal The LPRO is designed with a goal of ten years of maintenance free operation In order to accom plish this the major mechanisms impacting the need for maintenance were addressed Thus each LPRO has been design
15. spacing Single row housings can be converted into double row conneciors on 100 x 200 2 54 x 5 08 centers with the use of stacking clips Mini Tandem Spring Housings be stacked side by side or end to end on 100 2 54 centers 03 28 2000 Wire Applied Housings for Locking Clip Contacts Single Row 100 Centers Double Row 100 x 100 Centers Single Row Material Glass filled nylon 94 0 rated Related Product Data Contacts page 3175 Mateable Headers and Posts Refer to the Mating Post Selection Guide page 3142 Technical Documents page 3223 Double Row Material Glass filled nylon 94 0 rated Related Product Data Contacts page 3175 Mateable Headers and Posts Refer to the Mating Post Selection Guide page 3142 Technical Documents page 3223 Keying Plug Material Natural color nylon Part No 87179 1 Plugs directly into housings for 025 square post contacts 3176 Specifications subject to change For latest design specifications 1 800 522 6752 This dimension is 054 for the 1 position housing A 700 Note Housings illustrated above are the Both Ends Closed version Dimensioning Dimensions in inches SS Both Ends Closed a 4 RED 5 8 Both Ends Closed Keyway Both Ends Open Key M 89 X8 8 45 gy Right End Open
16. 5 0 102502 Rubidium Oscillator for Time amp Frequency Reference USER S GUIDE and INTEGRATION GUIDELINES LPRO Rubidum Oscillator Datum Proprietary Copyright 2000 Datum All Rights Reserved Printed in U S A This material is protected by the copyright and trade secret laws of the United States and other countries It may not be reproduced distributed or altered in any fashion except in accordance with applicable agreements contracts or licensing without the express written consent of Datum Irvine For permission to reproduce or distribute please contact Publications Supervisor Datum Irvine 3 Parker Irvine CA 92618 1605 Ordering Information The ordering number of this document is S O 102502D To order this document call 949 598 7600 and ask for the Datum Irvine Sales Department Notice Every effort was made to ensure that the information in this document was complete and accurate at the time of printing However the information presented here is subject to change Applicable Patents This product is protected under the following U S patent numbers 4 661 782 5 457 430 5 489 821 5 656 189 5 721 514 and patents pending Trademarks X72 is a registered trademark of Datum Other trademarked terms may appear in this document as well They are marked on first usage Warranty Datum provides a 2 year warranty on this product Table of Contents REFERENCES Additional Documen
17. 801150 822 8430 622 6441 64 85 78 13 377 78 74 3 100 3 801 150 LPRO User s Guide amp Integration Guidelines 31 03 28 2000 5 0 1025020 Withstanding Voltage Mates with no ei ce z TSW MTSW LCW BST 1 PINS TSS ZSS DW EW ZW ER ROW TLW TSM MTLW Features Low profile box 200 5 connector strips Top entry pass through entry dual entry horizontal entry New pass through entry for use with plated through holes zt T d tat Sr Dd zi Specifications BCS Insulator Material Black Liquid Crystal Polymer Flammability Rating UL 94 Insulation Resistance 5000 MQ min Operating Temp Range 65 C to 125 C Max Processing Temp 260 C for 10 seconds and 230 C for 30 to 60 seconds 1000 VRMS 60 Hz Contact Material Phosphor Bronze Plating S Au PANI or Sn over 50u 1 27um Ni Current Rating 1A Contact Resistance 0 MO max Lead Size Range 024 0 61mm SQ to 026 0 66mm SQ Insertion Depth 180 4 57mm to 290 7 37mm except HE is 180 4 57mm to 250 6 35mm Insertion Force 7 5 oz 1 39N avg 025 0 64mm SQ pin Withdrawal Force 3 oz 0 83N avg 025 0 64mm SQ pin Note Som
18. A DIV 50 00 Q START 5 000 000 000Hz BMIN 180 00 deg STOP 15 000 000 000Hz STOP 15000000 000 Hz 21593 Figure 3 7 rf Output Impedance Versus Frequency 3 4 1 3 ac Coupled rf Load The LPRO is designed to tolerate an ac coupled rf load without waveform distortion provided the coupling capacitor is low impedance at 10 MHz for example a 0 01 uF capacitor has an X of 1 6 ohms which is small compared to the fifty ohm nominal output impedance The rf output stage of the LPRO uses an ac coupled design It is recommended that the coupling capacitor be ceramic with a X7R or NPO dielectric LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 20 LPRO Design Integration Considerations 3 4 2 Transformer coupled rf Load The transformer coupled rf load is used to break up ground loops It can also be used to provide some bandpass filtering However it also attenuates the rf signal making it difficult to provide a tight tolerance on the rf output level It is also difficult to obtain an inexpensive off the shelf wide operating temperature range SMT rf transformer 3 4 3 Isolation of Chassis The LPRO can be electrically isolated from the user s chassis via a thermally conductive insulator and with the use of insulating shoulder washers for the baseplate insulation 3 4 4 Shorted Output Open Output Cases The LPRO is designed to tolerate a short to ground of the rf output without damage providing a rf output signal amplit
19. Mss ja 5 BE 44 Keyway Left End Open Housing No of A Housing Part No Configuration Dim Stamped Unstamped 1 108 87175 2 2 216 87175 6 3 316 87175 8 4 416 1 87175 0 5 516 as 1 87175 2 6 616 1 87175 3 1 87175 4 Single Row 7 DOAG 20 487175 5 1 87175 6 Born Ends 8 818 1 87175 7 1 87175 8 9 916 1 87175 9 2 87175 0 10 016 2 87175 1 2 87175 2 11 1416 2 87175 3 2 B7175 4 12 1 216 2 87175 5 2 87175 6 13 1 316 2 87175 7 2 87175 8 15 1 516 87175 3 87175 4 2 116 87176 2 4 216 87133 1 6 316 87133 8 87133 7 Double Row 8 416 1 87133 0 87133 9 Both Ends 10 516 87133 5 87133 2 Closed 12 516 1 87133 2 1 87133 1 _16 816 1 87133 4 1 87133 3 18 916 1 87133 5 20 1 016 87133 6 87133 3 Double Row 4 199 87125 1 Both Ends 10 499 87125 2 Open 20 999 87125 6 87125 3 Double Row 4 216 87132 1 Right End 10 516 87132 2 pen 20 1 016 87132 6 87132 3 Double Row 4 216 87131 1 Left End 10 516 87131 2 Cpen 20 1 016 87131 6 87131 3 Note Sea AMP Instruction Sheet No 15 7606 for proper contact orientation within the housings LPRO User s Guide amp Integration Guidelines 27 S 0 102502D AMP INCORPORATED HARRISBURG PA 17105 PHONE 717 564 0100 TWX 510 657 4110 PRODUCT INFORMATION CENTER PHONE 1 800 522 6752 03 28 2000
20. PULL TAGS Am CABLE AVAILABLE POSITIONS yt GEE GABLE aO ACCEZOR ES I SPECIFICATIONS _ i aan re ENVIBMONMENTAL L 16 rs z TEMPERATJAR H amp MBE 54 C TD 1265 70M 36b r2 2 MECHANICAL T 3 D IHSULATSA HATENIAL GLASS PLES POLYESTER BAST ti yawaq L 2 9 290 25 WZERTIDH a 4110 1 1 1 i 2 k Max 2 1 2 75 wa aoe W 1 TEP 2 B B IH x WITH ORS jaaa ep b m an a0 22 26 HmC MMEHUEKTZ SIPE F 55 ai 21 190 1 mnupa HOTES i ae 9 SEE OnDERLMG E PEHECLATLIBE HM Teoh ZTHa4lm af Tigw PORTION HAE IRR TUL FO armainEkmT LL STRAIN RELIEF E Steals AFi SP WITH STAGH POLARIZING TABS TL nee ne SPT T irELE Gr THU 40 Posi flows POLAGITIMG 22 aub PORTIONS ORLY Get 2660 8 ppor eL Sonos Sofie TiluzsL Am arinv _ a The afta
21. SCRIMINATOR isl which is nominally the 6 8346875 GHz VCXO VCXO SERVO LOCK IN AMPLIFIER RUBIDIUM PHYSICS PACKAGE fuon GENERATOR FREQUENCY MULTIPLIER SYNTHESIZER Figure 2 1 LPRO Rb Control Loop Block Diagram LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 102502 6 LPRO Installation amp Operation 2 2 Installation 2 2 1 Site Selection The LPRO installation site should be selected to maintain supply voltage and baseplate temperatures in the range of the specification of Section 1 The user should ensure that there are no strong magnetic fields at the site since LPRO is sensitive to external dc and ac magnetic fields refer to specification An external magnetic field under 2 gauss should not result in measureable permanent frequency offsets for LPRO 2 2 2 Cabling Suggested cabling is found in Section 4 0 Mechanical Thermal and Power Considerations for the LPRO NOTE always use shielded cable and connectors to minimize EMI emissions Ifdesired the LPRO is designed to directly mate to a user s interface board saving the cost and associated issues of interconnect cabling a drawing with suggested dimensions is also shown in Figure A 1 2 3 Turn on Procedure The LPRO does not have an ON OFF switch The unit is powered up by plugging in the unit s J1 connector to a properly terminated cable or the user s interface board Refer to Figure 2 2 for a block diag
22. able trim range once the warm up period has been completed If the XTAL V MON signal falls outside the range of 0 55 Vdc to 12 6 Vdc over the operating temperature range the unit should be removed for service by DATUM following the procedures described in Section 2 5 1 Repairs This allows roughly a half volt of margin before the crystal oscillator will lose lock to the stable rubidium frequency The crystal voltage will during sweep mode traverse through end points of 0 502V 017V on the low end and 13 3V 0 45V on the high end These design values are used to ensure that the normal operating limits are covered by the sweep signal while minimizing the wasted oversweep voltage LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 24 APPENDIX A LPRO Connector Data LPRO User s Guide amp Integration Guidelines 25 03 28 2000 5 0 1025020 interconnection Systems Selection Guide 82750 Revised 7 95 AV AMP Standard Tandem Spring and Mini Tandem Spring Receptacle Contacts Product Facts Individual contacts mate with 025 0 64 sq posts 125 3 18 long m Crimp snap in contacts accept 32 22 AWG 0 03 0 32 mm wire ar m Retention latch provides for positive installation WM No insertion tool required m High durahility design provides long life m Available with 000015 0 00038 or 000039 0 00078 thick gold inlay in contact areas or bright tin plated m Closed entry
23. ator to an external cesium clock or GPS satellite it can be readjusted periodically to match the primary standard s slower aging rate and greater accuracy There are two mechanisms to adjust the output frequency by the user Both methods result in a change in the current through a coil the unit s C field coil which is wrapped around the reso nance cell of the frequency standard in turn adjusting the internal magnetic field of the resonator There are two ways to manipulate the strength of the C field coil effect The first is electromechani cal by adjusting the external C field potentiometer accessible through a small hole in the top cover of the unit refer to Figure 2 2 Rotation of the slotted adjustment screw of the potentiometer pro duces frequency change Use of a small straight edge can accomplish this task A screwdriver is adequate Do not force rotation damage to the potentiometer can result LPRO User s Guide amp Integration Guidelines 06 09 2000 S 0 102502D 8 LPRO Installation amp Operation The second method of adjustment is electronic using the External C field control signal at pin J1 7 The unit is set to a nominal 2 5Vdc signal at the factory through this pin Increasing the voltage will increase the output frequency The allowable correction range is 0Vdc to 5Vdc al though positive voltages up to 36Vdc can be applied without causing damage or latch up Operating with negative voltages at J1 7 is not recommende
24. ave instead of a square wave because a sine wave lacks harmonics In addition the power consumption of the sine wave driver into 50 ohms is lower than for a square wave driver into 50 ohms especially when providing short circuit protection Because some users require a square wave for their application this section identifies a number of potential methods for the conversion Keep in mind that any circuitry shown must be verified by the user in their particular application And no endorsement of any specific manufacturer s product is intended Refer to Table 3 1 for a comparison of the phase noise resulting for each of the circuits based on a test sample of one Note that with the low noise source used there was no degradation in phase noise performance seen for the circuits illustrated in Figure 3 2 and only mild degradation for the circuit in Figure 3 3 3 4 1 1 1 ac coupled CMOS gate Two topologies are shown in Figures 3 2 and 3 3 The topology of Figure 3 3 has significantly less supply voltage sensitivity than that of Figure 3 2 but dissipates high power if the rf signal is re moved if implemented the user should be aware of potential reliability issues for this mode of operation The best logic family found for low phase noise is AC or ACT logic However the faster logic families such as AC and ACT logic have more EMI issues via the power and ground lines because they charge and discharge internal and external capacitances faster and
25. cs power The resonator heater power is determined primarily by the resonator control temperature of 78 C the baseplate temperature and the 15 3 C W thermal resistance from the resonator to baseplate The lamp heater power is determined primarily by the lamp control tempera ture of 110 C the baseplate temperature and the 53 C W thermal resistance from the lamp to baseplate The electronics power reflects nearly a fixed electronic current that is independent of input voltage due to the unit s internal 17 V regulator and is roughly independent of of baseplate tempera ture The heater powers are roughly independent of input voltage An equation to approximate quiescent input power consumption for the unit is Po Vps 280 mA 78 C T 15 3 C W C110 C T J 3 C W electronics pwr resn htr pwr lamp htr pwr This equation is only an approximation since it ignores effects like internal self heating power losses from the heater reverse protection diode and power losses from the heater current sense resistors The LPRO maximum baseplate temperature described in the specifications was based on a model where the unit was covered on five sides with one inch foam to simulate free convection in air as the heat sink baseplate was exposed to forced air The maximum operating baseplate temperature will be lower by several degrees C if the external air is hotter than the baseplate mounting An example is a situation where
26. d as latchup of the internal op amp can result when a voltage more negative than 8 Vdc is applied Using an external counter suitable for the task this operation requires a measurement accu racy that exceeds most counters adjust the unit so that the output rf frequency is 10 000 000 000 Hz NOTE if the LPRO s output signal frequency must be changed this can be done electronically by connecting the positive voltage of a low output impedance voltage reference to J1 7 and its return to J1 2 or J1 4 chassis ground The recommended output impedance is 1 k ohms for the reference voltage although a higher output impedance can be tolerated the input impedance for this signal is approximately 151 k ohms Increasing the positive voltage provides an increasingly positive frequency offset The correction voltage range is 0 to 5Vdc where no external frequency offset correction is nominally at 2 5 Vdc C FIELD ADJUSTMENT ACCESS HOLE 1416 Figure 2 3 Top View of LPRO Showing C Field Adjustment Access Hole LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 102502 9 LPRO Installation amp Operation 2 5 Maintenance 2 5 1 Repairs The LPRO is not field repairable If the unit should fail DO NOT REMOVE THE COVER OF THE UNIT and attempt to make repairs Instead call the DATUM Customer Support Group for the best way of returning the unit to DATUM Send to Customer Support DATUM Irvine 9975 Toledo Way I
27. ds for the impact on aging and other parameters but this is more of an issue for expensive laboratory fre quency standards with significantly tighter aging specifications than a LPRO unit LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 22 LPRO Design Integration Considerations 3 7 EMI CONSIDERATIONS 3 7 1 Outer Mu Metal Cover The resonator packages of rubidium frequency standards have significant frequency offsets due to external magnetic fields For this reason it is customary to use a double mu metal shield for the resonator housing in order to meet the magnetic susceptibility specification for the unit of parts in 10 gauss The LPRO was designed so that the unit cover forms the second outer magnetic shield The cover is made of mu metal with overlapping edges that minimize problems with fringing fields The advantage of this approach is the resulting magnetic shielding of the electronics outside of the resonator package 3 8 LPRO Susceptibility to Input Noise When a user has an application where the output spectrum phase noise and spur integrity is crucial the LPRO must be provided with comparatively clean source of dc power free of spurious current or voltage noise Connecting fans and other electromechanical devices to the dc supply powering the LPRO can result in degraded phase noise and spur performance This is because motors with brushes can create a wide spectrum of noise The frequency spectrum
28. e lengths Styles and options are non standard non returnable IMPORTANT NOTE DE Style connectors cannot be used with plated through holes for bottom entry E RI I E AEN z 2 SAMTEC INC 1347 Albany IN 47151 1147 USA Phone 1 800 SAMTEC 9 USA amp Canada 812 944 6733 Fax 812 048 5047 44 SAMTEC EUROPE LIMITED 117 Deerdykes View Westfield Cumbernauld gt Scotland G88 Tel 01236 739292 Fax 01236 727113 SAMTEC ASIA PACIFIC PTE LTD 1 Kallang Sector 05 01 Kotam Ayer Industrial Park Singapore 1334 Tel 85 745 5855 Fax 65 841 1502 Note Due to technical progress alf designs specifications and components are subiect to change withaut intima LPRO User s Guide amp Integration Guidelines 32 03 28 2000 5 0 1025020 3 465 Cu NU RUN 3 245 ata INTERFACING PW8 620 000 000 235 pem mone 1 gt En m e v 2 o a Uu 1 o a i t I m m e lt na ENT Figure A 1 Suggested Mating to Circuit Card Assembly LPRO User s Guide amp Integration Guidelines 33 03 28 2000 S 0 102502D
29. easy to integrate into a system requiring only one input supply voltage and allowing direct plug in connection into another circuit board It offers the high reliability ofa design that has been refined over many years from the experience gained in fielding tens of thousands of DATUM oscillators It is a one board package incorporating surface mount technology 1 1 Typical Applications The Model LPRO is a product DATUM offers for those requiring the high accuracy of a rubidium atomic frequency standard in their system design but at a price that is competitive with high perfor mance crystal oscillators The LPRO is designed for ease of integration into time and frequency systems because of its low profile and single circuit board design The height and footprint are de signed to accommodate 1U VME application or a 3U VME application Great care has been taken in the design to minimize EMI emissions and susceptibility including the use of both a filter plate connector for I O signals and an outer mu metal cover The LPRO complies with FCC Article 47 Code of Federal Rules Part 15 Class A Op eration is subject to the following two conditions 1 This device may not cause harmful interfer ence and 2 this device must accept any interfer encereceived including interference that may cause undesired operation The LPRO also complies with EN55022B and EN50082 1 see specifica tions LPRO User s Guide amp Integration Guidelin
30. ed to have sufficient rubidium fill in the lamp to last for the required period sufficient pulling range for the voltage controlled crystal oscillator and sufficient dynamic range of the rubidium control loop As stated in Section 2 with the exception of frequency adjustment via the fine frequency control potentiometer or the external C field adjusting signal there is no tuning that need be per formed by the user If problems arise in LPRO operation contact DATUM Customer Support for guidance The LPRO is considered to be factory serviceable only Monitor signals are provided to allow the user to track indicators of pending end of life for the unit with sufficient warning to avoid a total and sudden failure of the unit The key indicator of health for the operation of this atomic standard is the BITE signal If the unit BITE output is HIGH after the specified warm up period has ended a fault condition exists The LAMP V signal can also be monitored for inherent degradation of the internal pickup of the lamp light output by the photodiode this is often called light voltage decay or DCLV decay If the LAMP V signal drops below 3 Vdc the unit should be removed for maintenance If the LAMP V signal exceeds 14 Vdc the unit should be removed for service by DATUM following the proce dures described in Section 2 5 1 Repairs Similarly the crystal voltage monitor XTAL V MON can be used to show if the crystal is drifting out of the avail
31. eee A 23 34 T Outer MucMetal ict lee oneal ose det Gee elated 23 3 8 LPRO Susceptibility to Input 23 30 LPRO Maintenance sae a caren 24 3 9 CPRO io ipee atem ced 24 APPENDIX A and Board Connector Guidelines and Datasheets eene 25 LIST OF ILLUSTRATIONS Figure 1 1 EPRO Rubidium Oscillator 35 2 3 20 n eb Que boten dod eet 1 Figure 1 2 LPRO Outline Drawtng dp oe eee 2 Figure 1 3 Total Unit Power Dissipation Typical free convection 5 Figure 1 4 Representative LPRO versus Temperature rennen 5 Figure 2 1 LPRO Rb Control Loop Block Diagram 6 Figure 2 2 Suggested Connections for LPRO Initial Turn on eee 7 Figure 2 3 Top View of LPRO Showing C Field Adjustment Access 1 2 1 9 Figure 3 1 Interface Circuitry of LPRO Connector 16 Figure 3 2 Sine to TTL Conversion Using C MOS Logic Recommended Approach 18 Figure 3 3 Sine to TTL Conversion Using C MOS Logic Self Bias Approach 23 Figure 3 4 Sine to TTL Conversion Circuit Using Positive ECL Converter sse 23 Figure 3 5 Sine to TTL Conversion Circuit Using a High Speed Comparator 23
32. en utilizing the BITE signal Standard TTL and LS TTL draws too much current for the interface series output resistance of 2 kohms used by the LPRO while standard CMOS circuitry may oscillate during the slow transition through the active region during BITE level changes It is recommended that either Schmitt trigger CMOS logic for example 74HCT14A MM74HC14 74ACT14 and CD40106 or a high input impedance FET input comparator with hysteresis are used for the interface to the BITE signal LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 21 LPRO Design Integration Considerations 3 6 C Field Frequency Control 3 6 1 Greater Than 1E 9 Internal or External Control The C field control circuitry is designed to independently sum the contributions of the C field control potentiometer and the external C field control signal Each control signal gives greater than 1 5E 9 frequency offset correction capability The external C field control circuitry is designed so that with no voltage applied at J1 7 the voltage will self bias to mid range or 2 5V 3 6 2 Time Response of External C field Control The external C field control has a response time that is dominated by the rubidium servo loop band width which yields a typical time constant of 23 ms There are several other time constraints present but they are all more than a factor of 10 faster 3 6 3 Temperature Compensation of Frequency Using External C field Control
33. er s Guide amp Integration Guidelines 03 28 2000 5 0 1025020 30 Thomas amp Betts Mass Termination IDC Systems Dimensions shown are for reference only Dimensions are millimeters Female Socket Transition Connector 4 to 64 Positions Physical Properties Insulation Material Glass filled thermoplastic rated 94V 0 blue Contact Material Beryllium copper 30 inches minimum gold over 50 inches nickel in contact zone tin lead over nickel in termination area Electrical Properties Current Rating 1 Amp Insulation Resistance gt 1 x 109 Ohms 500 VDC Dielectric Strength gt 1000 sea level finches gt 225 SOCKET CONNECTOR yes 210 2204854 004 7 AFTER CRIMPING WITH STRAIN RELIEF 1651 pem BEFORE CRIMPING UE WITH STRAIN RELIEF i f Pol 10249 12 10 14 10 os MAX 15551 404 476 BEFORE CRIMPING AFTER CRIMPING WITHOUT STRAIN RELEE LA WITHOUT STRAIN RELIEF 1 CONTACT INDEX MARK THIS SLOTS OMITTED ON SIZES 14 amp SMALLER 5381 Environmental Properties 1 CONTACT 1150 2121 THIS SLOT IS OMITTED Temperature Rating 55 C to 125 C PN 2 ON SIZES 6 amp SMALLER vul et Sat Sat s PULL TABS doe 25413 1275 16 100 005 500 030 CATALOG NUMBER 5223287 826 32501 622 31 78 73 100 622 25PT_ 635 2 500 mB 822007 508 12 000 Ea
34. es 5 0 1025020 LPRO has been successfully applied to telecom networks such as digital cellular PCS basestations SONET SDH digital network tim ing etc Linked with a GPS receiver the LPRO provides the necessary timing requirements for cellular and PCS systems The low tem perature coefficient and excellent frequency stabil ity extend holdover performance when the GPS signal is not available The LPRO is designed for long operating peri ods without maintenance long life Rb lamp ex tended crystal control range with a goal to exceed 10 years The design provides a stable frequency with good short and long term stability and excel lent spur performance The LPRO provides a 5V CMOS compatible alarm signal derived from the basic physics operation which indicates when the output frequency is outside roughly 5E 8 of absolute frequency offset Shown with cover removed Figure 1 1 LPRO Rubidium Oscillator 1 06 09 2000 LPRO Rubidum Oscillator lt _ 1 50 gt MAX A O O i 22 1 700 oa 3 245 3 70 A 1 76 O O Y y y Y 4 2 938 gt lt 62 PIN 1 10 EMI FILTER PIN CONNECTOR 025 X 100 SPACING X 25L 020 010 6X 112 40 UNC 2B Figure 1 2 Outline Drawing LPRO TABLE la J1 Connector Interface PIN SIGNAL NAME RF OUT CHASSIS GND RF RTN CHASSIS GND CHASSIS GND LAMP VOLTS
35. et from Water Condensation 14 3 3 External Interfaces and 15 34 Bleetucal Interface SONG DR este let T ie 17 SAP ROME Output 17 3 4 1 1 Conversion of 10 MHz sine to 10 MHz TTL 17 3 4 1 1 1 ac coupled CMOS Gate 17 3 4 1 1 2 ECL TTL Level Shifter uc cette there 17 3 4 1 1 3 Use of a LT1016 Comparator 19 3 4 1 2 Output Impedance versus 20 5 4 123 ac coupled rf Logat 54 oss 20 3 4 2 Transformer coupled rf 1040 21 continued Table of Contents continued Section Three continued 34 3 Isolation OE Chassis e abite gita adiecto sse edades 21 3 4 4 Shorted Output 21 3 5 Built in Test Equipment BITE 2 2 21 3 5 1 Recommended Customer Interface to BITE 2 2 0 22 22 21 21 3 6 C Field Prequeney Control retro ee el wees 22 3 6 1 gt 1 9 Internal or External Control 2 2 22 3 6 2 Time Response of External C field 22 3 6 3 Temperature Compensation of Frequency Using Ext C field Control 22 3 7 EMI Considerations cae ted
36. hout loss of lock All scenarios are defined in terms of the unit s baseplate temperature the bottom surface of the bottom cover and are described below 1 Temperature range 35 C baseplate to 20 C baseplate This operating temperature range allows full frequency control but excludes normal warm up The cold temperature limit is based on the use of a 30 C 85 C unheated crystal and an internal temperature rise at the crystal of 6 C The hot temperature limit is based on staying under the maximum operating temperature of the crystal avoiding loss of thermal control of the resonator heater and not exceeding the operating derating guidelines of selected LPRO components 2 Temperature range 30 C to 70 C The normal operating temperature range with speci fied warm up capability included This temperature range excludes that of scenario 1 because of the unheated crystal used in the LPRO The unit will not be damaged when operated between 35 C and 30 C but a guaranteed performance cannot be ensured until the circuit board near the crystal begins to warm a 6 C rise occurs thirty minutes to one hours after turn on 3 Temperature range from 70 C to 75 C baseplate This is the emergency operating tem perature range that maintains lock but has no guaranteed warm up period The upper limitation is derived by staying under the upper operating temperature of the crystal as well as avoiding the loss of thermal control of the resonato
37. l contact from the bottom baseplate of the LPRO to the mounting surface in order to achieve the highest ambient operating temperature for the specified LPRO operating baseplate temperature It is also very important to maintain a uniform heat sink temperature because of uneven heat flow into the baseplate of the LPRO through its various mount ing points For this reason the LPRO Accessory Kit DATUM P N 102509 001 includes thermal tape DATUM P N 102515 001 precut for the LPRO outline and mounting hole pattern LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 11 LPRO Design Integration Considerations 3 2 2 Test Heat Sink A heat sink or mounting base plate is required to keep the baseplate temperature under 70 C Internal self heating of the LPRO will cause local internal temperatures to exceed DATUM s part derating guidelines when used without a heatsink or forced air although the maximum manufacturer s operating temperature ratings will not be exceeded A heat sink with thermal resistance to ambient of less than 2 C W is required for ambient of 50 C maximum For test purposes an optional heat sink is available Order P N 102518 001 from DATUM 3 2 3 Impact of External Ambient Air Temperature on Unit Operation The power consumption for LPRO versus baseplate temperature is shown in Figure 1 3 The behav ior is dominated by three mechanisms the resonator heater power the lamp heater power and the electroni
38. on operating 200 ft to 70 000 ft Magnetic Field Sensitivity dc 2 GAUSS Worst Vector refer to LPRO data sheet P N 102502 Relative Humidity lt 85 non condensing meet or exceed Telcordia GR 63 CORE Issue 1 October 1995 section 4 1 2 Vibration Meets or exceeds Telcordia GR 63 CORE Issue 1 Operating October 1995 section 4 4 3 and section 5 4 2 no unlock 1 0 g peak sine 5 100Hz Non operating Telcordia GR 63 CORE Issue 1 October 1995 transportation section 4 4 4 and section 5 4 3 curve 10 LPRO User s Guide amp Integration Guidelines 3 06 09 2000 5 0 1025020 LPRO Rubidum Oscillator Environmental Specifications continued EMI Complies with FCC 47CFR part 15 subpart B emission requirements for a class B device when connected with shielded cable and connectors in accordance with Section 2 2 2 Cabling and Section 4 0 Mechanical Thermal and Power Considerations for the LPRO Additionally the LPRO complies with FCC Article 47 Code of Federal Rules Part 15 Class A Operation is subject to the following two conditions 1 This device may not cause harmful interference and 2 this device must accept any interference received including interference that may cause undesired operation The LPRO also complies with EN55022B emissions radiated and conducted and EN50082 1 immunity MTBF Per Telcordia GR 63 CORE Issue 1 Ground Fixed Controlled Amb Temp 20 C 25 C 30C 40C 50 60
39. r This condition is not recommended for long operating period because once heater control is lost the unit may take on a frequency offset typically parts in 10 that will be present for many days of operation while the unit returns to equilibrium Also DATUM part derating guidelines are exceeded under this condition although the component manufacturer s maximum part rating guidelines are not provided the baseplate temperature is kept below 75 C LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 13 LPRO Design Integration Considerations When thermal control is lost the result is a large rate of change of frequency versus tempera ture As the baseplate temperature increases the unit will eventually lose lock As described in the Theory of Operation section of this manual the physics package acts as a discriminator that com pares the injected microwave frequency to the hyperfine transition frequency of rubidium 87 6 834687500 GHz The output signal drops rapidly as the resonator temperature increases above the set point When the output signal drops low enough the unit can no longer maintain internal lock When the resonator or lamp heaters shut down because no power is required to sustain control point temperatures the unit temperature coefficients are about 5E 10 C temperature change 3 2 5 Frequency Offset from Water Condensation Condensation of moisture from the air onto electrical components will produce freq
40. ram of a suggested hook up SCOPE ON OFF PE OR S CHASSIS GND SPECTRUM 424V NOM ANALYZER 50 PWR RTN I eem CHASSIS GND 1811 Figure 2 2 Suggested Connections for LPRO Initial Turn on The mating connector must provide power 19V to 32V 24Vdc nominal to J1 10 and power return to J1 8 The user s system power supply must be capable of providing a peak source of 1 7 amperes during the warm up period After warm up this power requirement drops to 0 5 amperes room temperature LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 102502 7 LPRO Installation amp Operation If the user s power supply is unable to provide the required peak amperage 1 7 amps the LPRO warm up times will be degraded If insufficient power is provided the unit may be unable to com plete warm up and a latch up condition will result This does not overstress the electronics of the unit However it prevents the unit from achieving lock It can also cause rubidium migration in the lamp which could prevent the unit from operating properly it would require servicing Connect the rf load to J1 1 sine 10 Mhz rf out and J1 2 rf out return Note that J1 2 is actually connected to the LPRO s chassis cover and internal signal grounds Monitor the BITE signal at J1 6 with respect to chassis ground at J1 2 or J1 4 using a high imped ance meter recommended gt 1 megohm input resistance
41. rvine CA 92718 1819 Telephone 949 598 7600 Fax 949 598 7876 to obtain return procedures from Customer Support Fax 949 598 7650 Marketing Fax 949 598 7651 Marketing LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 10 Section 3 Design Integration Considerations 3 1 Mechanical Issues 3 1 1 Recommended Mating Connectors Refer to Section 1 and Appendix A for information on appropriate mating connectors and manufacturer s data sheets 3 1 2 Circuit Card Mating Recommendations Refer to Appendix A for connector recommendations 3 1 3 Mounting Guidelines 3 1 3 1 LPRO Attachment to an external Chassis or Circuit Card Always use shielded cables and connectors refer to Tables 1 and 1b for the signal pin assignments and Appendix A for connector information The LPRO can also plug directly into a customer s circuit card assembly saving the cost of cabling Refer to Figure A 1 in Appendix A for details 3 1 3 2 Baseplate Mounting The LPRO has six mounting hole locations on its bottom cover that require a 4 40 screw with a minimum penetration depth of 1 8 The bottom cover can accept a maximum screw penetration depth of 1 25 without damage a longer screw will hit the top cover Torque each screw to 4 5 inch pounds minimum 5 inch pounds nominal when using the recommended stainless steel screw 3 2 Thermal Considerations 3 2 1 Use of Thermal Tape It is critical to obtain a good therma
42. t Figure 3 4 with Figure 3 3 used as a buffer since Figure 3 4 cannot drive the low 50 ohms test 4 Test Figure 3 5 with Figure 3 3 used as a buffer since Figure 3 5 cannot drive the low 50 ohms test 5V 43 2 ee L 68uF inert a TANTALUM TIL 33 2 10 MHz 10 MHz 47pF lt 5 pus LOGIC gt 49 9 1674 V V Figure 3 2 Sine to TTL Conversion Using C MOS Logic Recommended Approach LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 18 LPRO Design Integration Considerations 5V 43 2 ONES CMO05 68yF SINE OSCILLATOR LOGIC m 10V a 47 pF 10 MHz 10 MHz 49 9 51K Figure 3 3 Sine to TTL Conversion Using C MOS Logic Self Bias Approach SINE MC10ELT21D OSCILLATOR LOCATE AS CLOSE TO J2 9 01ygF 33 2 MC10ELT21D AS POSSIBLE Q Wer 33 2 TTL OUTPUT VW 10 MHz 0 1 pF V BB REFERENCE VOLTAGE 1579 OUTPUT 3 6VDC Figure 3 4 Sine to TTL Conversion Circuit Using Positive ECL Converter 3 4 1 1 3 Use of a LT1016 Comparator Figure 3 5 shows a sine to TTL converter using a high speed comparator The advantage of this approach is the lower supply and ground noise compared to the ac couple high speed CMOS ap proach The disadvantages are the higher phase noise and cost compared to the ac couple CMOS approach and the extra power dissipation 24 29 milliamperes more at 5V 3 4
43. tation __ iv SECTION ONE Introduction and Specifications 1 Ll Typical Applications ieu a ee OL 1 152 CPRO Specifications 3 SECTION TWO Installation and Operation 2 47 Theory Of Operauion eroe RETE t eu ea A 6 222 Ata Pat LE 7 2 21 SIE ele OTT 7 2 2 2 7 2 5 rotes sacan orti ident o UE 7 2 4 Frequency Adjustment Procedure 0 0 cee eeeesecsseceseceseeesscecsaeesseesseeeeaeeesaeenes 8 23 Mantenance 10 SECTION THREE Design Integration Considerations 3 1 Mechanical Grae M 11 3 1 1 Recommended Mating 11 3 1 2 Circuit Card Mating Recommendations esses 11 3 1 3 Mounting Gunde mes iannis 11 3 2 Thermal Considerations E i 11 3 2 Thermal ui 11 32 2 West Peal Sink aan Be eee eh se 12 3 2 3 Impact of Ext Ambient Air Temp on Unit Operation 12 3 2 4 Unit Operating Temperature Range eee 13 3 2 5 Frequency Offs
44. the baseplate is being cooled by a thermoelectric cooler but is exposed to nearby heat producing equipment If there is air flow over the unit s top cover the LPRO s maximum operating baseplate tem perature will increase by 1 or 2 degrees and its power consumption at a given baseplate tempera ture will also increase by a few tens of milliwatts LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 12 LPRO Design Integration Considerations 3 2 4 Unit Operating Temperature Range There are three scenarios of interest concerning the operating temperature range for LPRO The three scenarios are differentiated by performance for conditions including the turn on warm up period standard operation after warm up is completed and emergency operation after warm up is completed The turn on warm up period includes the time for the internal heater circuits to obtain thermal equilibrium for the lamp to ignite into a plasma discharge for the standard to achieve atomic lock and for the crystal operating temperatures to reach its normal operating temperature range The three scenarios are Scenario 1 The operating temperature range below the normal temperature range without guaranteed warm up but with full frequency control Scenario 2 The normal temperature range with full performance including warm up Scenario 3 The operating temperature range above the normal temperature range excluding guaranteed warm up but wit
45. tor VCXO and applied to the Rb vapor within a glass container or cell The light ofarubidium spectral lamp also passes through this cell and illuminates a photo detector When the frequency of the applied rf signal corresponds to the frequency of the ground state hyperfine transition ofthe Rb atom an ultra stable high Q rubidium atomic resonance light is absorbed causing a change decrease in photo detector current I Asthe change in current is small modulation techniques are required to be able to extract the desired signal out of the noise background The dip in photo detector current is used to generate a control signal with phase and amplitude information which permits continuous atomic regulation of the VCXO frequency The servo section converts the photo detector current into a voltage then amplifies demodulates and integrates it for high dc servo loop gain The VCXO output signal is divided by 2 and fed through a buffer amplifier to provide the standard frequency output of 10 MHz This signal is also frequency multiplied x3 and fed to a step recovery diode multiplier mixer circuit along with the modulated synthesizer frequency of 5 3125 MHz 17 64 x 20 MHz to generate the microwave frequency Ignoring modulation components the microwave frequency component f selected by the high Q resonator is 114 x 3 xf 17 64 x f rubidium frequency at f a 20 MHz VCXO PHYSICS BUFFER Po Rb DI
46. ude at approximately twice the normal output level of that from a fifty ohm load This condition actually provides the worst case stress on the rf output driver stage transistor but the derating guidelines are still followed for this part less than 125 C junction temperature at the maxi mum operating baseplate temperature 3 5 Built In Test Equipment BITE Signal The LPRO provides an indication that the internal Voltage Controlled Crystal Oscillator VCXO is locked to the atomic transition via the BITE signal As long as the BITE signal is LOW once warm up is completed the user can be assured that the output frequency is within roughly 5E 8 of abso lute frequency If the BITE signal is high atomic lock has been lost and the VCXO will go into sweep mode to reacquire lock The sweep ranges approximately from 17 ppm to 18 ppm in approximately a 20 second period Note that during this lock acquisition period a cumulative time error can be expected The resulting overall time error will average out during the sweep period to that obtained from a constant frequency offset at roughly the net difference between the sweep endpoints although nonlinearity of the sweep will give further errors 3 5 1 Recommended Customer Interface to BITE The internal LPRO BITE signal interface includes components for EMI filtering and ESD protection see Figure 3 16 The internal filtering impedance and response times must be taken into account by the user wh
47. uency spikes or instability until the heat of the operating unit drives out the water vapor Condensation is more of a problem when a cold unit is warming up rapidly because the temperature of the internal surfaces of the LPRO will lag the temperature changes of the outside ambient air and an influx of hot humid air will hold enough moisture to condense out on the colder surfaces Condensation will not cause a problem for environments meeting the LPRO specification if the LPRO baseplate thermal ramp rates are controlled so that they rise at less than 2 C minute LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 14 LPRO Design Integration Considerations 3 3 EXTERNAL INTERFACES and GROUNDING Figure 3 1 shows interface circuitry for J1 the LPRO I O connector All signals including power power return rf output signal chassis ground and monitor lines are routed through this connector The LPRO is constructed with the chassis unit cover and signal grounds tied together at multiple points and with the power supply return isolated from both chassis and signal grounds only by a ferrite bead This robust grounding approach allows for ESD protection and low spurious emissions But it can also lead to ground loop issues for the user Workarounds commonly used to break dc ground loops at a higher level of integration are to isolate the LPRO cover chassis from the user s chassis use a rf isolation transformer for the 10 MHz rf o
48. unction properly in a connector housing j 2 Extraction tool No 91084 1 is used for removing individual contacts from connector housings and for detaching contacts from mating posts Extraction Tool Part No 91084 1 3175 28 03 28 2000 ELED DEAD emi Et AR ECORHERDE ATDIuG 2 ELECTRICAL RaTiHus 1 VOLTAGE wea lkl kGTMIC wITHZTauDimd wo Yamp RESIETauE g SESIS ance 2J E 1D Hle nn H HJ HI HATING CA PRHDDUCTi HUMBER OF 1 BE F CONTACT POSITIONS 1 INSULATION UISPLACEMENT SOCKET SERIES 2 CORP ib TROAAS LPRO User s Guide amp Integration Guidelines S 0 102502D ARIS INSU Ligier 10 64 200 C aan Sm arme 7 METERS 29 C EE TH ETGT TTE BEAZLURED THANN ATIO Pee B nan2 GOLS See opgorm onde HITEL SSP RAT E T PLATING ROEDeTAET rer 1 LEPMELF Er o m 9 ura adiu pri FEATURES ABULATT UIM v UHFZHHZ 72 HIL ilienjgg TE d s PIN TD WIRE i oh TALC TLC FINOLE SIUE wreE CONTADT iar 5 BTHAlm
49. utput and or float the transformer secondary winding of the user s power supply J1 signals are routed through a filter plate selected for EMI and ESD purposes Three filter pin types are utilized for the filter plate 1 1000 pF PI feedthrough capacitor ferrite for power power return and monitor signals 2 470 pF PI feedthrough capacitor ferrite for the rf and dc isolated rf return signals and 3 shorting pin for the two chassis ground pins either one of which is the recommended rf return pin LPRO User s Guide amp Integration Guidelines 06 09 2000 5 0 1025020 15 LPRO Design Integration Considerations FILTER IMPEDANCE er em 2 500 NOM 10 MHz CHASSIS GND RF RTN 5V 9 12 R434 R435 CHASSIS GND 2NDHLOCK 0401 AA VA 13 1 0K 1 0K 5 THKF THKF 74 08 0805 0805 C436 033uF 1670 0805 ISOLATED Ei 77 16686 J 1000PF ra NOTE alternate configuration TOC 10K Hs V MON is CR106 installed in place of THKF THKF F101 amp CR103 0805 0805 C312 1669 CR101 mm SMBYW 02 Te E gt 24VHTR CR106 0101 SMBYW 02 AUF 1206 Jt 2101 2102 F101 424V 10 gt 24VELEC 39 39 1A 1206 5 2 1 SB2 1 IN HOLDER C102 C137 gt C139 C103 103
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