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TLV1117: Vout overshoot during startup

Jason Dai
Expert 3720 points
Part Number: TLV1117
Other Parts Discussed in Thread: TLV767

Hello E2E,

We could see the overshoot issue during startup on TLV1117-18 converting 5Vin to 1.8Vout.

Is it normal?

if not, how to solve the issue?

BR,

Jason

  • 0
    TI__Mastermind 43580 points

    Hi Jason,

    Are those ceramic capacitors at the output? The  TLV1117 needs an effective ESR between 0.2 and 10 Ohms:

    if these are ceramic capacitors, adding series resistance to meet the ESR requirements could help to reduce this overshoot. Note a modern update to the 1117 is the TLV767. 

    I hope this helps.

  • 0 in reply to JCHK
    TI__Expert 3720 points

    John,

    We try to remove the original ceramic cap and add a 4.7uF Electrolytic capacitor, but the overshoot issue.

    we just want to know if it is normal behavior on TLV1117-18?

    in addition, is TLV767 p2p with TLV1117-18? If yes, could TLV767 fix overshoot issue at startup?

    BR,

    Jason

  • 0 in reply to Jason Dai
    TI__Mastermind 43580 points

    Hi Jason,

    I believe the overshoot issue you are seeing is simply due to the lack of inrush control. Unfortunately, the TLV1117 is a very simple regulator. 

    As for the TLV767 unfortunately it is not P2P with the TLV1117 as in addition to superior inrush control it has an enable pin and a remote sense for fixed versions. This helps to improve regulation accuracy over load. 

    I hope this helps.