TPSM63603: SYNC before EN

Ruixin Feng

Part Number: TPSM63603

Hi team,

In customer application, sync will firstly apply to tpsm63603 and then Vin will apply. With Rent=560kohm，Renb=100kohm, TPSM63603 can't power on. But with Rent=Renb=100kohm, TPSM63603 can power-on normally. Could you pls help to explain this?

Besides, customer want to know if with Rent=Renb=100kohm, sync before EN, will it cause any risk?

Thanks!

Rayna

over 1 year ago

0 Marshall_Beck over 1 year ago

TI__Mastermind 28400 points

Hello Rayna,

It sounds like the customer will need to revise their solution.

In section 7.3.7 of the datasheet we require: "The external clock must be off before start-up to allow proper start-up sequencing."

So, Vin up, En up, and then sync.

0 Ruixin Feng over 1 year ago in reply to Marshall_Beck

TI__Intellectual 1765 points

Hi Beck,

yes the datasheet is clear, but in customer application, sync is before Vin. So customer want to learn if this will cause some risk. Could you pls help me to understand why with different resistor division can cause different result?

Rayna

0 Marshall_Beck over 1 year ago in reply to Ruixin Feng

TI__Mastermind 28400 points

Hello Rayna,

Yes, sync before Vin is a risk and can cause indeterministic operation.

The termination you are creating could be impacting the amplitude of the voltage which the device is seeing and causing issues with the startup sequence, hence, the recommendation of not having sync before Vin.

Power management

Power management forum

TPSM63603: SYNC before EN