TPS25910: Can Enable be powered with no VIN?

Mark Guastaferro

Part Number: TPS25910

Application usingTPS25910 eFuse will supply 3.3V to EN pin and FLT pin (through 5K pull-up) with no voltage applied to VIN.

Is this acceptable? Will device be damaged or have excessive leakage.

Assumming this is OK, the data sheet mentions that FLT output becomes operational when VIn is above 1V. So could the FLT pin output the wrong state as VIN powers up (EN still = 3.3V)?

over 7 years ago

0 Aramis P. Alvarez over 7 years ago

TI__Genius 10370 points

Hi Mark,

I'm moving this thread to the appropriate forum.

Best Regards,

Aramis P. Alvarez

0 Rakesh over 7 years ago

TI__Guru** 102701 points

Hi Mark,

This is acceptable configuration. There is no concern on functionality if pull-up resistor is used.
I will verify FLT pin output and update you.

Regards,
Rakesh

0 Rakesh over 7 years ago in reply to Rakesh

TI__Guru** 102701 points

Hi Mark,

The FLT pin output is operational even when EN is above V(EN)rising threshold (1.5V). While VIN powers up, FLT output will pulse low momentarily as seen in the attached test waveform.

Regards,

Rakesh

0 Mark Guastaferro over 7 years ago in reply to Rakesh

TI__Genius 11235 points

Hi Rakesh,

Thank you for the quick reply.

One additional question regarding the EN input. Does it have any protection diodes on the pad, particularly diodes to VIN? My original assumption was that VIN would be floating when off, but if it is pulled to ground or has some ressitance to ground, then an internal diode on the EN pin might conduct.

0 Rakesh over 7 years ago in reply to Mark Guastaferro

TI__Guru** 102701 points

Hi Mark,

Resistor-diode network is present from EN pin to Vin pin. Even when Vin is grounded, the resistor limits the current sourcing capability in the path from EN Pin to Vin Pin and it should not raise any concern.

Regards,
Rakesh

0 Rakesh over 7 years ago in reply to Rakesh

TI__Guru** 102701 points

Hi Mark,

Do you have any further questions? If not I would like to close this thread.
Please let us know.

Regards,
Rakesh

0 Mark Guastaferro over 7 years ago in reply to Rakesh

TI__Genius 11235 points

Hi Rakesh,

I think we are good on this question. Go ahead and close the thread.

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TPS25910: Can Enable be powered with no VIN?