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LMZ14203EXT: LMZ14203EXT - EN pin function

Sanket Pathak
Prodigy 30 points
Part Number: LMZ14203EXT

I am working on one design where I am using LMZ14203EXT to generate 3.3V rail.

This power IC has EN pin which enables the output volt when voltage at this pin crosses 1.18V while going up and disables output when voltage at EN pin is lower than 1.09V while going down (Due to 90mV hysteresis).

At EN pin I have some observations. If there is voltage glitch at EN pin and voltage recovers within 40-50 us then 3.3V output is stable. But if glitch is approx.100us then 3.3V output face volt degradation.

The question I have here is, what is reaction time for output to react on EN pin status? or what is minimum pulse width needed at EN pin to disable output.

Thanks,

Sanket 

  • 0
    TI__Genius 15380 points

    Hi Sanket,

    There's no spec that defines deglitch filter time for EN. The result you have is consistent with what I got. I tested the device by hooking up a function generator to EN, and roughly ~80uS was about the limit of when the negative pulse would shut off the device (at full load).

    Also It depends on how much current is being delivered at the load. When I removed the load, VOUT takes some time to degrade, and by the time it degrades a little, VOUT is back up because it's enabled again.

    Please verify with your set up that the device performs to the specifications you need for your application.

    Thanks,

    Andrew