LM27762: How much current can the PGOOD pin safely sink?

Jacob Quant

Part Number: LM27762

I would like to directly drive an LED, if possible, at about 1mA when the regulator outputs are operating normally. e.g. wiring +12V through 10K to the LED anode and then connecting the LED cathode to the PGOOD pin of the LM27762. Will this be OK or do I need to add something else to drive the LED instead? (e.g. base/gate of transistor)

over 6 years ago

0 Chris Glaser over 6 years ago

TI__Guru**** 151530 points

Hi Jacob,

I searched with 'LM27762 PG' and found this thread: e2e.ti.com/.../673449

I would note that you can't use a 12V pull-up voltage as this is above the rating of the IC. You need to drive PG from Vin.

0 Jacob Quant over 6 years ago in reply to Chris Glaser

Prodigy 30 points

Thanks for helping me find that, Chris. It would be nice if the datasheet specified an absolute maximum voltage for all of the pins. (Currently Section 6.1 only lists VIN, VOUT, EN+, and EN-. Since PGOOD is open drain it seems reasonable the it might have a higher voltage rating.

I will drive the LED from VIN (+5.1V) and a 2k resistor then (for I_led <= 1.5mA).

0 Chris Glaser over 6 years ago in reply to Jacob Quant

TI__Guru**** 151530 points

Thanks for your feedback. There should be a link at the bottom of most of the pages in the D/S to get that improvement routed to the right people.

Power management

Power management forum

LM27762: How much current can the PGOOD pin safely sink?