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TLVH431: Cload P.M

Part Number: TLVH431
Other Parts Discussed in Thread: TLV431

Hi Team,

I find the schematic showing as below, and the Cload recommended value is 0.1uF 

I'm not sure relationship between CL and PM. I see when Cload = 0.1uF, the PM~0degree

So when we use 10uF, the PM is almost 70 degree in red line. Does it mean 10uF is better than 0.1uF?

And when we use RC filter in VSUP side, does it have impact to PM?(because they are in the same node)

  • Hi Roy,

    I need to change the example recommended capacitance. I would not recommend 0.1uF for the load capacitor for that example. Please use a value greater that will give a phase margin lager than 30 degrees for stability purposes. In this case 10uF will give greater than 30 degrees.

  • Hi Marcoo,

    I see this sentences showing in datasheet, does that mean we don't need to use any CLoad in the circuit, right?

    But I think it may have a side-effect when no using CLoad. Do you know any side effect without CLoad?  

    Unlike many linear regulators, TLV431 is internally compensated to be stable without an output capacitor between the cathode and anode. However, if it is desired to use an output capacitor Figure 18 can be used as a guide to assist in choosing the correct capacitor to maintain stability

     

     

  • Hi Marcoo,

    One more question, If IC temp is changed, the P.M will be have an big impact or not?(If cap is constant) I couldn't find the information in datasheet.  

  • Hi Roy,

    We have an offline email but I still wanted to touch base and respond to the points in this E2E.

    The TLV431 is internally compensated so the device works with no load cap across temperature.

    The TLV431 becomes unstable when the stability pole changes from the internal compensation cap to the external load cap which is around 0.1uF. Before 0.1uF the internal cap controls the stability. After 0.1uF the load cap controls the stability.