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TLV733P: EN pin current

Antenna_Head
Genius 11395 points
Part Number: TLV733P

Team-

We have a scenario where Vin = 0V, but EN might be high.  Often there is some sort of ESD diode from the EN pin to VIN of the device, and current from the EN pin could bootstrap VIN through said diode. 

In the past, we would work around this by adding a series resistor (~10K) in the EN wire to limit this current to something safe, perhaps < 1 mA.

The data sheet for the TLV733P doesn't indicate any limits for how much current the EN pin can tolerate if Vin = 0V.

Please let us know what a safe value of current would be.

Thanks, Best, S. Dunbar, AFA Colorado

  • 0
    TI__Guru 55940 points

    Hi Steve,

    You are correct that there is an ESD diode between EN and Vin.  As it is an absolute maximum rating violation to have Ven higher than 0.3V above Vin, we have not characterized or tested EN pin current with Vin = 0V.

    Very Respectfully,

    Ryan

  • 0 in reply to Ryan Eslinger
    TI__Genius 11395 points

    Ryan-

    Thanks; I did see that, but it isn't particularly helpful in this case.  That spec basically indicates the presense of the diode, but doesn't really address what is a safe amount of current to pass through it in light of the exponential I/V relationship of diodes.  

    The customer intents to bias the EN line through a 10K resistor, up to 3.3V logic.  

    Under these conditions, we would expect LESS THAN 3.3V/10K = 330 uA of current to flow.  In my past experience, this has always been a safe level.

    Can you please comment on the value, as the data sheet does not put an upper limit on the amount of current that can be injected into EN pin?

    Thanks, Best, Steve

  • 0 in reply to Antenna_Head
    TI__Genius 11395 points
    Also, I did try to simulate this just now and it appears the ESD structure on the EN pin isn't modeled at all.
  • 0 in reply to Antenna_Head
    TI__Guru 55940 points
    Hi Steve,

    While we have not tested or characterized this diode for this kind of application, we would expect 1mA to be ok.

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    TI__Genius 11395 points
    Thanks much, I suggest adding some spec here for future devices. This topic actually comes up quite a bit in heavily power managed systems.