TPS51200-Q1: VTT has overshoot and the highest voltage is 9V

Amelie Zheng

Genius 10865 points

Part Number: TPS51200-Q1

Hi Team,

During the testing the timing, VTT has overshoot and the highest voltage is 9V.

The input voltage of 1.2V and 3.3V are good without overshoot. Any advice about this?

0 Zhao Gao over 2 years ago

Hi Amelie,

Is the overshoot at 9V or 0.9V? It looks like it is 0.9V on your scope.

What is the output cap value and is this overshoot cause any glitch or spike on VDDQ/VREFIN?

if you increase the output cap, does that help?

Best,
Zhao

0 Kadeem Samuel over 2 years ago in reply to Zhao Gao

Amelie,

Are you able to capture a scope measurement that has VTT, REFIN, VDD_3V3, and VLDOIN?
Thanks,

Kadeem

0 Amelie Zheng over 2 years ago in reply to Zhao Gao

Sorry Gao, this is 0.9V. And I update the waveforn as following

0 Amelie Zheng over 2 years ago in reply to Kadeem Samuel

yellow---VLDOIN

blue---VDD3V3

pink---VTT

green---REFIN

Please kindly help to give some advice, customer this case is quite urgent

0 Kadeem Samuel over 2 years ago in reply to Amelie Zheng

Amelie,

This issue can be resolved by changing the power sequence by having the 3.3V source go high before VLDOIN, per this thread: e2e.ti.com/.../3824539 .

Thanks,

Kadeem

Power management forum