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Replies: 2
Views: 47
Part Number: OPA2348
Hi Experts:
I found an issue of OPA2348 in customer's system , see the schematic attached . The input from CON1 is the signal generator,
The gain is 1000V/V, we input the 2mV and 66HZ sine waveform ,the output signal is only 1V , which is not correct.
I also check the bandwidth gain and think it should be OK for the 66HZ input, and i also do the simulation in the TINA, It also OK .
So could you please tell what's wrong with it , is it the Vos issue ?
If some parameter of the OPA2348 can't support this case, is there any device you recommend?
IC2-A.TSC
Hello Jason,
I think you have the wrong gain set up with your resistors. Currently, you have 100MOhms in the feedback and 100Ohms before that. That will give you a gain of 1,000,000V/V. Was this intended?
Regards,
Daniel
Hi Jason,
the chosen gain is way too high. The OPA2348 shows a maximum input offset voltage of up to 6mV. This would result in an output voltage of 6mV x 1000 = 6V (without the diodes in the feedback loop). So, even the least offset voltage will make the diodes turn on.
Kai