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LM7171: Input offset voltage drift

Lars Veurink
Prodigy 20 points
Part Number: LM7171

Hi all,

I'm looking at the LM7171A and need some clarification from the datasheet.

I suspect that there is a difference between the A and B version of the LM7171 (regarding the input offset voltage drift). 
If you take the specification from the datasheet: TCVOS: 35uV/C and compare this to the 2 figures in the datasheet:
Figure 5-3 (LM7171A) Input Offset Voltage vs Temperature, calculating the drift from this (+-15V): -40C=-1mV and 100C=0.2mV. This gives 1.2mV / 140C = 8.5uV/C
And figure 5-42 (LM7171B) Input Offset Voltage vs Temperature, calculating the drift from this (+-15V): -35C=2mV and 125C=-4mV. This gives 6mV/160C = 37.5uV/C
Given the large difference between the calculated value and the spec given on page 4 (TCVOS): Is this spec only applicable for device B or both A and B? 
What is the correct drift specification for device A? The graph or the number given in the datasheet?
Thanks in advance!
  • +1
    TI__Genius 13665 points

    Hi Lars,

    We apologize for any confusion and lack of clarity. We are currently in the process of changing our wafer technology which we have released a PCN for and can be found here. The old silicon has a Vos drift spec of 35uV/C like shown in the datasheet for both versions A and B. This old silicon will be available till an estimated date of May 2 of this year. After the given date you will now be able to purchase the A version on the new silicon as we will not have a B option. However, with this version, the new Vos drift spec will be updated to reflect the results shown in Figure 5-3.

    Best Regards,

    Ignacio

  • 0 in reply to Ignacio Vazquez Lam1
    Prodigy 20 points

    Hi Ignacio,

    Thanks for the quick reply and clarity! The next question then would be: are there any cleaned up versions of the datasheet available? So, where the 'old' silicon values are removed from the datasheet?

  • 0 in reply to Lars Veurink
    TI__Genius 13665 points

    Hi Lars,

    I spoke to the systems team, and unfortunately, we currently do not have a datasheet available but the updated version can be expected sometime in May.

    Best Regards,

    Ignacio