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Original question:

LM2936: LM2936 3.3V version and 22uF output cap

LM2936: is it okay to use 10uf Cout?

Marvn Arcangel
Genius 12395 points
Part Number: LM2936

Hi Team,

Our customer is using our voltage regulator LM2936 to generate 3.3Vout however, they only used a 10uF ceramic cap instead of the recommended 22uf for Cout from the datasheet.

The customer claims that they had no stability issue all over the temp range, and the dynamic load current response is excellent and stable. They also tested the load step response to ensure stability and the result is stable.

In addition, the customer suspects that using 10uF cap instead of recommended 22uF may reduce the phase & gain margin, but the regulator will be still in the stable region. Can you confirm this? 

Can you also confirm if the customer can use Cout=10uF while the input is 14Vin? they assume the 22uF is required for stability in Vin high ==> 40V.

Hoping you can help.

Regards,

Marvin

  • 0
    TI__Genius 12960 points

    Hello Marvin,

                         For the 3.3V output voltage version we recommend that at least 22uF of output capacitance be provided to ensure stability across devices. Once the device is in regulation, typically the frequency response of the loop gain (and hence stability) does not change with the value of input voltage. Thanks!

    Regards,

    Srikanth