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OPA4140: The minimum value of the slew rate.

Kengo.Y
Guru 10385 points
Part Number: OPA4140
Other Parts Discussed in Thread: OPA140, OPA2677, , TL072

Hi team,

I'd like to know about the minimum value of the slew rate.
Of course, I know this value is not specified in the datasheet. (Just write TYP)
I'd like to know it for our reference.

Sincerely.
Kengo.

  • +1
    Guru 47485 points

    Well in theory scaling that down by the min vs typ supply current ratio would be a first estimate, but there is no min supply current either??

    Long time ago I tried to set up a spec table format that covered all of this in a very condensed form, and it did, but never got picked up elsewhere, 

    Here is an example from the OPA2677 datasheet, this dual CFA was widely designed into DSL line drivers, so those customers were demanding this kind of info regularly. I had noticed a lot of the datasheet spec tables (like the OPA140) are a lot of white space - here, each column is a different temp range min or max depending on the type of spec, and that is called out over on the right as well as a test level - B means simulation. 

  • +1
    TI__Guru* 93105 points

    Hi Kengo,

    If your original slew rate question was about the OPA4140 TI cannot make any assurances for a parameter that is only specified with a "Typical" specification. What we can provide is an estimate of what its minimum or maximum might be. 

    Based on the process variables for the semiconductor process the OPA4140 uses the estimate is the slew rate can vary about +/-30 % from the typical 20 V/µs number.

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • +1
    Guru 140200 points

    Hi Kengo,

    the usual remedy is to choose an OPAmp with lots of headroom so that you don't need to worry about manufacturing tolerances and variations due to aging.

    Let's have an example: For an audio application a suited OPAmp is searched which needs to handle 20kHz with 1Vp amplitude. Slew rate of this signal is 1Vp x 2 x pi x 20kHz = 0.13V/µsec. So when taking a TL072 with a slew rate of 13V/µsec, e.g., everything is fine.

    Kai