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Original question:

LP5907: the impact on phase margin of LP5907 by remote output capacitor

LP5907: The output noise , bandwidth and load transient of LP5907 with/without nearby output capacitor

michael YANG
Prodigy 195 points
Part Number: LP5907
Other Parts Discussed in Thread: TLV733P

Hi Team,

We know the LP5907 is design base on remote output capacotor .

Could you please share the test data on the  the output noise , bandwidth  and load transient of   LP5907  with/without nearby output capacitor ?

I want to ensure the impact of remote output capacitor .

If it is possible ,please share the theory of  LDO with  remote output capacitor.

Great  thanks for your support in advance .

  • 0
    TI__Guru 55940 points

    Hi Michael,

    Unfortunately since LP5907 was originally developed by National Semiconductor before TI purchased them, any comparison between a remotely located output capacitor and a output capacitor local to the OUT pin of the LDO was lost in the transition.

    The only difference between a remote capacitor location and the normal OUT pin location for an output capacitor will be the additional ESR and ESL from the trace itself.

    The advantage of placing a capacitor up to 10 cm away from the LDO is that it allows for the flexibility of placing a single capacitor to cover both the LDO output capacitor requirements and the load's input capacitor requirements.

    Additional information about using a remote capacitor can be found in section 8.2.2.7 of the datasheet.

    Very Respectfully,

    Ryan

  • 0 in reply to Ryan Eslinger
    Prodigy 195 points
    Hi Ryan,
    Thanks for your reply .
    is there other chip with remote output capacitor ?

    Thanks！
  • 0 in reply to michael YANG
    TI__Guru 55940 points
    Hi Michael,

    I am not aware of another LDO that specifically mentions a remote output capacitor. We do have other LDOs such as TLV733P that are stable without any external capacitors and therefore are stable with remote output capacitors as well.

    If performance is a concern, we would recommend placing the pads for a a capacitor on your board next to the LDO pin. This way while doing your prototyping if you find additional capacitance is needed, you can add the local capacitor.

    Very Respectfully,
    Ryan