TPS62813-Q1: Is there any risk that EN goes to high ready before Vin start up

Eddie Chen1

Prodigy 150 points

Part Number: TPS62813-Q1
Other Parts Discussed in Thread: TPS62813, LM73606

Hi,

TPS62813 : Vin=5V and Vo=1.1V or 1.8V

The input voltage of TPS62813 is from the output of LM73606 (LM73606 12Vin to 5Vout)

Both of LM73606 and TPS62813 EN signal are tied to the same source.

Is there any risk if TPS62813 EN signal goes to high ready before its Vin start up? (I think the LM73606 will have a non-monotonic output start up waveform)

Will it cause IC damage if voltage on EN-pin larger than Vin-pin?

over 2 years ago

0 Stefano Panaro over 2 years ago

TI__Expert 7685 points

Hi Eddie,

Thanks for your question.

Are you cascading LM73606 and TPS62813?

The potential problem that I see is that, if the output waveform of LM73606 is not monotonic around the UVLO of TPS62813, this could cause the device to oscillate between an off and on state. This does not seem likely looking at LM73606 startup waveform on its datasheet, but this should be tested on the actual PCB.

To have a 'cleaner' solution, I would advise to connect the EN of TPS62813 to the PGOOD pin of LM73606.

Thanks,

Stefano

0 Eddie Chen1 over 2 years ago in reply to Stefano Panaro

Prodigy 150 points

Thanks Stefano.

Can I connect TPS62813 EN-pin to Vin-pin direct? Or need a current limit resistor, ex. 10kohm.

+1 Stefano Panaro over 2 years ago in reply to Eddie Chen1

TI__Expert 7685 points

Hi Eddie,

You can connect EN/VIN pins. EN is a digital input.

Thanks,

Stefano

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TPS62813-Q1: Is there any risk that EN goes to high ready before Vin start up