TPS3808: A voltage spike at the RST_N output upon power up

Ee Kou Chong

Part Number: TPS3808
Other Parts Discussed in Thread: TPS7A8101

Noticed that there is a small voltage spike at the RST_N output from TPS3808G33DBVT on our board upon power up. The datasheet did mention with voltage below 0.8V, the RESET_N output will be in undefined state. Would like to confirm the waveform we are observing are correct.

over 5 years ago

0 Trailokya Rai over 5 years ago

TI__Genius 11401 points

This waveform is not violating any spec. It is expected.

I am curious to know why VDD waveform has fast ramp rate in starting and then it becomes slow? What kind of supply you are using and what is the supply decoupling cap?

Regards

Trailokya

0 Ee Kou Chong over 5 years ago in reply to Trailokya Rai

Prodigy 30 points

Hi there,

I'm using LDO from TI (TPS7A8101). According to the datasheet, the ramp up is fast then slow down eventually (with startup delay). Decoupling cap is 10uF. Thanks.

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TPS3808: A voltage spike at the RST_N output upon power up