LM25149-Q1: VDDA start up delay

Shinji Tsuji

Genius 14179 points

Part Number: LM25149-Q1

Hi team,

How long is the EN to VDDA start up delay?

I measured it and it varies 0.1ms to 2ms.

Is it the expected value?

regards,

0 Orlando Murray over 1 year ago

Hi Shinji,

This variation is just one board?

No I dont think this variation is expected on one board.

When EN goes above 0.5V, the device should start charging VCC capacitor.

The delay should only depend on VCC capacitor and VCC current limit.

I would expect VDDA to follow VCC.

Let me know if it's varying on one device.

-Orlando

0 Shinji Tsuji over 1 year ago in reply to Orlando Murray

Hi Orando-san,

Thank you. There might be residual charge on VCC cap. I will check it.

regards,

0 Orlando Murray over 1 year ago in reply to Shinji Tsuji

Hi Shinji,

Alright let me know. 100us sounds correct, but 2ms seems like alot, unless there is significant VCC capacitance.

-Orlando

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