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TPS7A4701-EP: prop delay & timing of EN pin to output for shutdown

Part Number: TPS7A4701-EP

Team - quick question:

Assuming that the linear regulator is up and running steady state and then the the enable pin of the part gets pulled down with a fast edge (using a small signal mosfet, a digital gate, etc).

How long does it take for the LDO to respond to this command and shut the output off?

  • Hi Michael,

    I measured these times on an EVM.  The delay time from when the LDO see's a positive enable pulse to when the output begins ramping up is roughly 3ms.  The delay time from when the LDO see's a negative enable pulse to when the output is no longer regulating is about 50us.  Remember that the LDO does not sink current, it can only source current, so once the LDO is no longer regulating, the output voltage will collapse back to zero volts based on the amount of load on the output.  I used a 10 ohm resistor as the load in this case.

    Green = Channel 1 = EN voltage
    Purple = Channel 2 = Vout

    Thanks,

    Stephen