DS90UB947-Q1: Power up sequence

Tomoaki Yoshida91

Genius 5255 points

Part Number: DS90UB947-Q1

Hi team,

There is not description for power up sequence in datasheet.

I understand that VDDIO, VDD18 and VDD11 startup sequence is not required.

Is my recognition correct?

Best regards,

Tomoaki Yoshida

over 8 years ago

0 Palaniappan Manickam over 8 years ago

TI__Genius 10475 points

Yoshida-san,

The 947 datasheet talks about the power-up sequencing under power supply recommendations section. VDDIO/VDD18, followed by VDD11, wait until all supplies have settled and then activate PDB.

The recommended delay from VDDIO/VDD18 to VDD11 is 200us to 1.5ms and a delay of minimum 30ms from OLDI PCLK being stable to releasing PDB.

0 Tomoaki Yoshida91 over 8 years ago in reply to Palaniappan Manickam

Genius 5255 points

Hi Palaniappan-san,

Thank you for your support.
I read the power supply recommendations section in datasheet, but I could not understand the recommended delay from VDDIO/VDD18 to VDD11 is 200us to 1.5ms you say.
Please tell me the part that is written.

Are there any order and recommended delay for VDDIO and VDD18?

Best regards,
Tomoaki Yoshida

0 Palaniappan Manickam over 8 years ago in reply to Tomoaki Yoshida91

TI__Genius 10475 points

Yoshida-san,

Both VDDIO and VDD18 can be either ramped up together, or VDDIO delayed by atleast 200us after VDD18.

The current DS90UB947 datasheet does not have the delay values for power-up sequencing, but it will be included in the next update of the datasheet.

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DS90UB947-Q1: Power up sequence