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LMV604/Maximum value of Input bias current

Other Parts Discussed in Thread: LMV604, LMV344, LMC6001

Hi all.

Could you tell me maximum value of Input bias current about LMV604?

The reference data is no problem.

 

In addition, LMV344 is listed the input bias current(max), but LMV604 isn't listed it.

Please tell me this background .

Since LMV604 is inexpensive than LMV344, I think it is in order to reduce test cost.

Best Regard,

Sho Ogane

  • Hello Sho,

    Yes. The LMV604 is a cost-reduced version of the LMV344. They are the same die but tested to "looser" specifications with some guarantees removed. The less we have to test and guarantee - the lower the cost.

    You can use the maximum Ibias number from the LMV344 datasheet as a guideline, but it is NOT guaranteed on the LMV604.

    Bias currents are a function of the ESD diodes, which are pretty consistent across the devices - so I would expect them to behave the same on the LMV344 and the LMV604.

    Again, ibias is not guaranteed on the 604....that's the tradeoff for the lower cost.

    Regards,

  • Hi Paul san.

    Thank you for the reply.

    I understood the LMV604 is a cost-reduced version of the LMV344 and they are same die.

    But  input bias current of the LMV344 is 1pA(typ)  @Ta=25°C, the LMV604 is0.02pA(typ) @Tj=25°C.

    Could you tell me why are they so much difference?

     

    In addition, the schematic is not described on data sheet of LMV344.

    Is LMV344 JFET input? 

    Best Regards,

    Sho Ogane

  • Hello Sho,

    The more specs we "guarantee", the lower the yield. The lower the yield, the higher the cost per unit...pretty simple.

    We loosen the specs to allow more units to pass - and charge less for the devices.

    When we drop tests, we have to "pad" the specs to allow for any possible process variations.

    Bias currents are generally guaranteed by design or characterization. We cannot test sub-pA in mass production in the allotted test times (except for the LMC6001 - which is tested to 25fA - but you pay for it).

    Which Schematic? The datasheets are nearly identical.

    The input is CMOS - even better than FET's for sub-pA bias currents.

    Regards,

  • Hi Paul.

    Thank you for your response.

    Sorry, I will ask same question again.
    According to your first reply, the LMV604 and the LMV344 are same die.
    However, Ibias(typ) is difference between the LMV604 and the LMV344.
    Also please see the attached pictures as Ibias vs. temperature data from the datasheet.
    These figures are difference too. 

    I think that the Ibias(typ) should be same in same die.

    Could you tell me the reason for the difference in Ibias(typ) value between the LMV604 and the LMV344?

    I understood that LMV604 is not guaranteed Ibias(max) , however please let me know this reason.

    Best Regards,

    Sho Ogane