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Replacing AD624 with AD8295

Question asked by anantha on Feb 10, 2012
Latest reply on Feb 15, 2012 by anantha

Hi all,

 

We are using AD624 Instrumentation Amplifier for our signal Conditioning Application for Strain gauge based sensor like Force and Torque Sensors.  Here we get Voltage in mV and we are using AD624 as IA and then a second order Butter worth filter using OP177.

We are planning to replace AD624 with AD8295 IA, due to space constrains of AD624.

 

We have few doubts regarding how to implement the same circuit using AD8295.

1. We have implemented a offset null circuit in AD624[to null the offset voltage coming from the sensor] using the pins 4 & 5[Input Null].  As there is no such pin as Input Null in AD8295, please suggest us circuit which we could you to null offset either before or after AD8295.

2. Further we are using pins 1 and 8[VosTRIM] of OP177 to fine tune the Zero Voltage of the output.  Please suggest a circuit where we can do the same without using the VosTRIM Pins, as we are planning to use small Op-Amp array IC where VosTRIM pin wont be available.

 

I have attached the circuit that we are using, for reference.

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