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TPS54140A: Pull down in Enable pin Query

Omprakash Sankaran

Prodigy 70 points

Part Number: TPS54140A

I'm using TPS54140A for 3.3V regulation from 5V input. I have used a 10K pull down to the EN pin of this regulator to keep it off during power ON.

through software control, I will make Enable pin high (1.8V) to turn ON the regulator when needed. 
But by during power ON itself I can see 2.6V output at the regulator output. my doubt is that whether this 10K pull down is not enough. Could you clarify on this.

Please refer the below snap for schematics reference.

over 1 year ago

0 Marshall_Beck over 1 year ago

TI__Mastermind 30430 points

Hello, with R23 removed is this voltage seen?

I believe 10Kohm should be a sufficient pull-down alone and that voltage maybe coming from the GPIO pin of downstream device.

0 Omprakash Sankaran over 1 year ago in reply to Marshall_Beck

Prodigy 70 points

Hello, thank you for the reply.

If R23 is removed then the voltage is 3.3V. only when 10K is assembled the output is 2.6V.

The GPIO is now floating, no voltage coming from that pin now. since the processor is not assembled.

0 Marshall_Beck over 1 year ago in reply to Omprakash Sankaran

TI__Mastermind 30430 points

You are welcome.

Can you try one thing:

Could you reflow the board and replace the unit (if possible)?

It sounds like a net is open on the board.