DS90UH925Q-Q1: DS90Ux925 Power up sequence

Ryuuichi machida

Guru 11515 points

Part Number: DS90UH925Q-Q1

Hi,

I would like you to confirm about below.

* Could you please tell us "min" time from "VDDIO/VDD33" to "PDB" ?

I understood that "max" time from "VDDIO/VDD33" to "PDB" according to following sentence of datasheet.

"The VDDs (V DD33 and V DDIO ) supply ramp should be faster than 1.5 ms with a monotonic rise."

However, there is no description about "min" time.

According to DS90UB921, this "min" spec is defined as "0.05ms". Can we apply this spec to DS90Ux925 as well ?

Best Regards,

Machida

over 6 years ago

0 Palaniappan Manickam over 6 years ago

TI__Genius 10475 points

Hello,
The min time before asserting PDB would be 0. i.e. PDB can be asserted high as long as the VDDIO/VDD33 supplies are ramped up completely and at stable levels.

0 Ryuuichi machida over 6 years ago in reply to Palaniappan Manickam

Guru 11515 points

Hello,

Thank you for your reply.

I understood for requirement of PDB in case of "Power up".

Let me confirm about below as well.

* could you please tell us "min" time which PDB must be held LOW when togging PDB LOW after "power up" ?

According to DS90Ux928, this time is defined as shown below.

"Toggling PDB LOW will POWER DOWN the device and RESET all control registers to default. During this time, PDB must be held LOW for a minimum of 2 ms."

We need same spec for DS90Ux925 as well.

Best Regards,

Machida

0 Palaniappan Manickam over 6 years ago in reply to Ryuuichi machida

TI__Genius 10475 points

Are you referring to this statement in the Ux928 datasheet?

"A minimum low pulse of 2ms is required when toggling the PDB pin to perform a hard reset."

A similar number of 2 ms for PDB low pulse can be used for 925 as well.

0 Ryuuichi machida over 6 years ago in reply to Palaniappan Manickam

Guru 11515 points

Hi,

Thank you for your reply.

>Are you referring to this statement in the Ux928 datasheet?

No, but this also describes same one.

I referred 7.3.6 Power Down (PDB). And also there is same spec in section 6.6 as well.

>A similar number of 2 ms for PDB low pulse can be used for 925 as well.

Could you add this min "2ms" in datasheet ?

Best Regards,

Machida

0 Palaniappan Manickam over 6 years ago in reply to Ryuuichi machida

TI__Genius 10475 points

We have the power up sequence noted down as one of the additions to be included in the next version of the datasheet.

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DS90UH925Q-Q1: DS90Ux925 Power up sequence