User Guide - Avago Technologies
Contents
1. Setup of Evaluation Board Schematics Schematics of the Evaluation Board are as shown in Figure 2 V dd3 CONI yi holy C8 100nF 100nF GND2 GND2 GND2 C10 68pF_ R7 10K 194 O 1uF A aH svoz 6 4 u4 OPA237UA J3 A GND1 1 1 1 i i 1_Vdd1 ACPL C79X_1 TM78L05ACM TI a 1 eae rome u2 La 41 voi 1 VDD2 r 3 Batt Gnd1 Cl ileal c A 100nF 100nF 100nF 1 CON1X3 H GND1 GND1 GND1 GND1 GND1 i 1 R2 A Rsens A T Vin 4 Vout 10R 1 i RI TP4 i 1 c i TPS 22nF i R3 4 i Rsense l AMW Vin Vout 10R 1 H i GND1 t 4 1 Gnd Gnd2 1 i T H 1 1 1 1 i Figure 2 Schematics of ACPL C79X Evaluation Board Board Description The ACPL C79X evaluation boards shown in Figure 3 can accommodate either a ACPL C79B 0 5 tolerance ACPL C79A 1 tolerance or ACPL C790 3 tolerance device on U1 to demonstrate the high linearity and low offset capability of Avago s Isolation Amplifier over a wide range of input current conditions It allows a designer to easily test the performance of the high precision isola tion amplifier in an actual application under real life op erating conditions Many of the circuit recommendations discussed in Application Note 1078 are implemented on the board Operation require2. ACPL C79B ACPL C79A amp ACPL 790 Ava GO Isolation Amplifier Evaluation Board User Manual TECHNOLOGIES User Guide Quick Start Guide Once visual inspection is done to ensure that the Evaluation Board is received in good condition the Evaluation Board can be powered up in just 3 simple steps according to Figure 1 as shown 1 Select either one of the provided sensing resistors 10mQ or 15m or user s own sensing resistor and mount it through soldering on pads provided for R1 on the Evaluation Board 2 Connect the necessary power supplies and current source as shown a Connect 1st isolated 5V DC supply DC Supply 1 to connector CON1 as shown b Connect a 3 3V DC supply DC Supply 2 can be non isolated to connector CON2 as shown c Connect through soldering the required input current source for sensing cables as shown 3 Supply the input current subject to a maximum signal level of 250mVpp or 125mVdc across resistor R1 through the cables as shown in 2c and monitor the output through an oscilloscope 5V Gnd1 3 3V Gnd2 CPL C79X EVALUATION BOARD REV 1 0 02FEB10 Di VDD C2_2 UDD2 VDD3 C8_2 DC Supply 2 al UDD2 UDD3 o 3 vourl L p Output to Current Source Cables m UDD3 Oscilloscope for sensing for monitoring Taa or MCU for Readings C14 C10 R7 RS CS C15 TP2 TP3 TECHNOLOGIES www avagotech comvoptocouplers K100106 Figure 1 Default Test
3. is at pin 3 of Connector CON2 1 Sa 50 0 mv 2 a 200 mv 3 Sa 4 on D H i Vout 19 eet T ejas x H 100p wfelitfooe u Figure 4 Vout vs Vin Voltage Waveforms For product information and a complete list of distributors please go to our web site www avagotech com Avago Avago Technologies and the A logo are trademarks of Avago Technologies in the United States and other countries Data subject to change Copyright 2005 2011 Avago Technologies All rights reserved Ava G oO AVO02 2502EN July 14 2011 TECHNOLOGIES
4. oard TP2 TP3 K100106 Table 1 Recommended Vin for better linearity Vdd1 Vdd2 Vdd3 Vdd3 Default Setup 1 lt 230mVpp 5Vdc 3 3Vdc 3 3Vdc ov Setup 2 lt 500mVpp 5Vdc 3 3Vdc 3 3Vdc 3 3Vdc Setup 3 lt 230mVpp 5Vdc 5Vdc 3 3Vdc ov Setup 4 lt 500mVpp 5Vdc 5Vdc 3 3Vdc 3 3Vdc Setup 5 lt 440mVpp 5Vdc 5Vdc 5Vdc oV Setup 6 lt 550mVpp 5Vdc 5Vdc 5Vdc 5Vdc Notes 1 Linear input range is limited by the post amp output swing range To avoid this limitation directly measure the VOUT VOUT of the isolation amplifier In order to satisfy the above Vdd1 Vdd2 Vdd3 and Vdd3 voltages J1 J2 J3 and J4 must be set according to the table as shown below Table 2 yt J2 3 J4 Remarks Default Always Shorting Vdd2 Short Open Only 2 external supplies 5V Vdd1 amp isolated 3 3V for Vdd2 are Setup1 shorted amp Vdd3 pins needed Setup2 Always Shorting Vdd2 Open Short 3 external supplies 5V Vdd1 isolated 3 3V for Vdd2 and Vdd3 shorted amp Vdd3 pins while isolated 3 3V for Vdd3 are needed Setup 3 Always Shorting Vdd3 Short Open Only 2 external supplies 5V Vdd1 amp isolated 5V for Vdd2 are shorted amp C8_2 pins needed Vdd3 is obtained thru converter U3 Setup4 Always Shorting Vdd3 Open Short 3 external supplies 5V Vdd1 amp isolated 5V for Vdd2 while shorted amp C8_2 pins isolated 3 3V for Vdd3 are needed Vdd3 is obtained thru converter U3 Setup5 Always Shor
5. s merely the addition of a 5V Supply and a low resistance shunt resistor on the in put side of the isolation amplifier The board has holes for mounting a through hole shunt and pads for mounting a surface mount shunt The board may also be used for general voltage isolation without any shunt resistor As can be seen on the board the isolation circuitry is easily contained within a small area while maintaining adequate spacing for good voltage isolation and easy assembly The overall size of the evaluation board has been enlarged to allow mounting of feet for stand alone use using the 4 drilled holes at the corners of the board Using the Board The evaluation board is easily prepared for use Only mi nor preparations just by soldering of shunt resistor wires for power sense current path and output signal are re quired The evaluation board is having a default setup 1 as shown in the tables when shipped to customer Customer is free to choose any one of the 6 setup configurations as shown in the tables by setting J1 J2 J3 and J4 as shown ACPL C79X EVALUATION BOARD REV 1 0 O02FEB10 VDD1 C2_2 UDD2 UDD3 C8_2 Jz c2 J2 R4 m i al Coe J4 T1 co m m VDD1 9U GND1 CON1 uE TP4 R2 Rsense I i Rsense C14C10 R7 RS CS C15 vaGo TECHNOLOGIES WWW avagotech comvoptocouplers Figure 3 Top View of ACPL C79X Evaluation B
6. ting Vdd2 Short Open Only 2 external supplies 5V Vdd1 amp isolated 5V for Vdd2 amp shorted amp Vdd3 pins Vdd3 are needed Setup6 Always Shorting Vdd2 Open Short 3 external supplies 5V Vdd1 isolated 5V for Vdd2 amp Vdd3 shorted amp Vdd3 pins while isolated 5V for Vdd3 are needed Notes 1 To obtain 5Vdc at Vdd1 a 9V Battery can be connected across Pin 2 and 3 of CON1 connector or by connecting an external 5V DC supply directly to Pin 1 and 3 of CON1 connector J1 can be left shorted permanently unless U2 is non functioning The output signal is measured between the Vout and GND2 terminals at the output side of the board With all con nections made and power supplies turned on the approximate relationship of output voltage to input current is Vout 8 2 x Vin where Vin Rsense X lin With the shunt resistor in place the maximum differential input voltage swing for linear operation is 200mV as speci fied in the datasheet However input voltage as high as 300mV can be safely applied with minimal performance degradation When 68pF capacitance is selected for both C9 and C10 the bandwidth will be limited to 150kHz To obtain 200kHz bandwidth change both C9 amp C10 to 47pF Output Measurement A sample Vout against Vin waveforms are captured and shown in Figure 4 below Orange and Green traces are the input and output voltages respectively Vin 100 mV 50kHz Vout is taken at U4 Vout node which
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