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OPA2192: Possible replacement for OPA2192 and INA818

Ahmet Inan
Intellectual 450 points
Part Number: OPA2192
Other Parts Discussed in Thread: INA821, OPA4192, INA818, , OPA2141, OPA2140, OPA2210, INA823

Hi TI Technical Support Team,

I am using precision OPA2192 (OPA4192) opamp and INA818/INA821 instrumentation amplifier in my design. My circuit sweeps the voltage of the test device or applies square wave to it and measures the resulting current and voltage. Sweep rate sometimes can be as low as 20uV, so the opamp must have very low offset voltage. Also resulting current can be very low, so I need very low input bias current. Right now, I can not find these opamps and INA's in stocks (Digikey, Mouser). I searched for possible replacement for them. For INA818/INA821 I could not find any available replacement. And for OPA2192, I found OPA2141 with similiar specs but its input offset voltage was high (1mV) for my application. 

Could you please recommend me some possible opamps and INA that I can use in my design? If there is not any replacement, what strategy should I use for OPA2141 to deal with its high input offset voltage? Application note or reference design would be very helpfull. 

Opamps specs I need for my design

  • Input bias current: <100pA
  • Input offset voltage <10uV
  • GBW: 10MHz
  • Supply: ±18V (or ±15V)
  • High slew rate: >10V/us

INA specs I need for my design

  • Low input offset: <100uV
  • Supply:  ±18V (or ±15V)

Thank you for your help,

Ahmet

  • +1
    TI__Genius 10850 points

    Hi Ahmet,

    Thanks for your post, I can help you.

    In regards to the OPA2192, the OPA2140 is a good replacement with stock. However, the input offset voltage is inherent to the device so there is no way to reduce this externally. You may also consider taking a look at the OPA2210. Here is a spec-spec table:

    In regards to the INA818/821, you may take a look at INA823. Here is a quick spec-spec table: 

  • 0 in reply to Tamara M Alani
    Intellectual 450 points

    Hi Tamara,

    OPA2140 and INA823 seem good replacement for OPA2192 and INA818 in my circuit. I saw some app notes that was mentioning nulling input offset voltage, so that is why I was confused. 

    Thank you for suggestions and helping me.

    Regards,

    Ahmet