AM5728 Power Up Sequencing between vddshv8 and OSC0

Steven Liu1

Other Parts Discussed in Thread: TPS659039-Q1

Dear Champion,

My customer met one issue with power up sequencing between VDDSHV8 and OSC0.

As shown in the datasheet, the requirement is as below, it seems the OSC0 should after VDDSHV8 powering up.

However, this is the test result from the oscilloscope: the OSC is comming before VDDSHv8. Does this lead to a reliability issue?

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

Are they using the recommended PMIC? What is the clock source - oscillator or crystal?

0 Steven Liu1 over 9 years ago in reply to Biser Gatchev-XID

TI__Expert 4455 points

Hi Biser,
they used the TPS659039-Q1, so this is controlled by the PMIC. but it still has such observation. So customer is very curious about the power up sequencing.
Besides, they used the crystal but not oscillator.

0 Biser Gatchev-XID over 9 years ago in reply to Steven Liu1

TI__Guru**** 393215 points

There isn't a specific requirement for oscillator start-up timing related to VDDSHV8, so this shouldn't be an issue.

0 Steven Liu1 over 9 years ago in reply to Biser Gatchev-XID

TI__Expert 4455 points

Thanks, Biser

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AM5728 Power Up Sequencing between vddshv8 and OSC0