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TLV2462A: TLV2462 capacitive load driving capability

Dilip Namdeo Mohol
Intellectual 1420 points
Part Number: TLV2462A
Other Parts Discussed in Thread: TLV2462

                             One of my customer is using TLV2462 rail-rail op amp for pressure sensing application in our product. As per datasheet if capacitive load more than 10pf then suggested to use min 20ohm resistor in series, what will be the maximum capacitive load that op amp can drive without degrading performance?. Initially they  used 1K resistor in series for 0.1uf capacitive load but at some point of time op amp output limited around 3.5V even though change in input voltage. They tried tweaking resistor value for proper response and then we got expected results with resistor <470ohm(Finally used 100ohm and 0.1uf). Please let us know the op amp response here with high value resistor.

  • 0
    TI__Genius 15410 points

    Hi Dilip,

    The resistor R4 in their schematic will not stabilize their amplifier. For the resistor to stabilize the amplifier it must be outside of the feedback loop as shown in Figure 49 of the datasheet. For more information I recommend watching our TI Precision Lab videos on Stability. They are likely seeing a degradation in output voltage swing because the output of the amplifier must overcome the drop across the 1k resistor inside of the feedback to make the feedback point (at the cap load) the expected output voltage. Reducing the resistor to 470 ohms improves the output swing because there is not as large of a voltage drop when compared to a 1k ohm resistor.

    If the customer moves the location of the resistor to be like what is shown in Figure 49, does their issue go away?

    Thank you,

    Tim Claycomb

  • 0
    TI__Genius 15410 points

    Hi Dilip,

    Has the customer tried the recommendations? If so, did it correct their issue?

    Thank you,

    Tim Claycomb

  • 0 in reply to Tim Claycomb
    TI__Expert 6625 points

    Hi Dilip,

    Can you please let us know if this issue is resolved? If not, can you please reply with the latest update?

    Best Regards,

    Bala Ravi

  • 0
    TI__Genius 15410 points

    Hi Dilip,

    It has been approximately 2 weeks since we last heard from you, therefore I am going to close this thread. If you still need support please let us know and we would be happy to help you.

    Thank you,

    Tim Claycomb