Problems simulating INA 332 in Pspice

Sergi Consul

Other Parts Discussed in Thread: INA332, TINA-TI

Hi!

I'm simulating a very simple amplification circuit with the INA332 in Pspice. I got the Pspice model from (http://www.ti.com/adc/docs/midlevel.tsp?contentId=55102).

What I'm trying to do is to amplify a very low voltage signal, from 10uV to 100uV and amplify it by 505. In the next figure, you can see my circuit in Capture, that then is simulated in Pspice.

And here is the problem,it is saturating the output when it shouldn't, here the simulation:

But, if I simulate the same circuit in TINA-TI, everything is OK:

So, What am I doing wrong? The configuration of the Pspice is the default.

over 13 years ago

0 Pete%20Semig over 13 years ago

TI__Mastermind 25865 points

Hello Sergi,

Can you please post your PSPICE and TINA simulation files?

0 Sergi Consul over 13 years ago in reply to Pete%20Semig

Prodigy 20 points

I'm attaching it.8463.Circuits.rar

Thanks!

0 Pete%20Semig over 13 years ago in reply to Sergi Consul

TI__Mastermind 25865 points

Hello Sergi,

Thanks for your patience.

Can you please try an input common-mode voltage of 0.5V instead of 1.5V? This would require disconnecting V11 from the input and connecting a new DC source set to 0.5V to the non-inverting pin of the INA332. Leave V11 connected to REF and R9.

This scenario enabled me to simulate the circuit in PSPICE. However, please note that I did not get the same failed output as you did when Vcm=1.5V. When Vcm=1.5V my simulation failed to converge.

In the end the model works for me (I imported it myself into PSPICE), but my concern is that it may not adhere to all relationships between the supply voltage, the input common mode voltage, and and reference voltage. I hope this helps.

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Problems simulating INA 332 in Pspice