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OPA196: Voffset

Ohad Bonneh
Intellectual 1970 points
Part Number: OPA196

Tool/software:

Hi Team, 

We are using the OPA196IDBVR in our design and need clarification regarding its input offset voltage drift.

According to the datasheet, the typical value is specified as <0.5 μV / ⁰C at VS=±18V, VCM=(V+)-3V, but there is no maximum value provided.

 

Could you please confirm:

 

  • What is the maximum input offset voltage drift at VS = +12 V / -10 V, VCM < (V+) - 3 V?
  • If this information is not available to share, otherwise could you recommend a pin-to-pin compatible operational amplifier with a guaranteed maximum input offset voltage drift of <0.5 μV/°C that can be used as an alternative to the OPA196IDBVR?

 

Your support will be greatly appreciated.

  • 0
    TI__Guru* 77521 points

    Hi Chad, 

    Ohad Bonneh said:
    What is the maximum input offset voltage drift at VS = +12 V / -10 V, VCM < (V+) - 3 V?

    If you are operating within the Vee =  -10Vdc and Vcc = +12Vdc in dual supply range, the Vios (refer to input) should be approx. ±100uV, and the typical input offset is approx. ±0.5uV/C. The datasheet is configured as buffer, so you should see the op amp's offset in approx. ±100uV ± 0.5uV/C (typical). OPA196 is etrimmed op amp. You should try to avoid the Vcm between 8-9V region as shown in the plot below, if you concerned about the Vos related errors. One simply way is to increase Vcc to 15V range. My suggestion is to avoid the transitional region, if the offset is critical for the application. 

    The datasheet only reported the typical value. If I estimated in ±3σ rule, the max Vos_drift < 3*0.5uV/C or ±1.5uV/C region, which it should cover 99.7% of production samples. 

    BTW, you have to take into account the circuit's gain, where Vos is approx. gain*(±100uV ± 0.5uV/C (typical)) + other related parameters that may affect the Vos final figures (Aol, PSRR, CMRR etc.). 

    Ohad Bonneh said:
    If this information is not available to share, otherwise could you recommend a pin-to-pin compatible operational amplifier with a guaranteed maximum input offset voltage drift of <0.5 μV/°C that can be used as an alternative to the OPA196IDBVR?

    I am not sure what application you are working with. You may consider chopper amplifier as well, if the application is used as a buffer. 

    OPA191IDBVR (SOT-23-5) may be acceptable (depending on your requirements, this max. Vos_drift is guaranteed). Or use OPA188AIDBVR (SOT-23-5, zero-drift) if you want to be low, see the link below.  

    https://www.ti.com/product-category/amplifiers/op-amps/precision/products.html#p2192=Zero%20Drift

    If you have other questions, please let us know. 

    Best,

    Raymond