TPS62840: Unexpected startup delay after Enable goes high

Roland Melad

Part Number: TPS62840

The datasheet specifies a startup time of 200us unless the Enable signal ramps with Vin. Just at specified in the datasheet we have a delay of 2ms (10ms MAX) when Enable ramps with Vin, however the delay is about 2.7ms after Enable goes high when Vin has reached 3.6V. Do you have any idea what might be causing this behavior?

Below is the waveforms where in you can see that the device only starts to switch beyond 2.5ms

over 3 years ago

0 Excel Regidor over 3 years ago

TI__Mastermind 26706 points

Hi Ronald,

You are correct. The startup delay (tstartup_delay) should be 200us only based on the attached waveform.

To help you better, can you post the schematic diagram and PCB layout? If it is confidential, then I can send you a message so we can discuss it privately.

Best regards,

Excel

0 Excel Regidor over 3 years ago in reply to Excel Regidor

TI__Mastermind 26706 points

Hi Ronald,

Just a soft reminder.

Kindly share the schematic diagram and PCB layout so I can review them. If it is confidential, you can send it via private message here in E2E or TI email.

Best regards,

Excel

0 Roland Melad over 3 years ago in reply to Excel Regidor

TI__Intellectual 1185 points

Hi Excel,

I have sent it to your TI email due to proprietary concerns of our customer.

Regards,
Roland

0 Yann Ducommun over 3 years ago in reply to Roland Melad

TI__Intellectual 2605 points

Hi Roland,

I'm going to close this thread since the discussion will continue privately.

Thanks!

Yann

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TPS62840: Unexpected startup delay after Enable goes high