TCA6408A: Question about difference between TCA6408A datasheet version SCPS192D and SCPS192E.

Kazuya Nakai59

Guru 20130 points

Part Number: TCA6408A
Other Parts Discussed in Thread: TCA6416A

Hello guys,

One of my customers received PCN of TCA6408A and TCA6416A recently.
Also each device datasheet versions are changed from SCPS192D to SCPS192E for TCA6408A and from SCPS194E to SCPS194F for TCA6416A.
We checked different point between new and old version. But we couldn't find any spec difference, package dimension and explanation difference except the following description in 10 Power Supply Recommendations section on page 31 and 29.
”Ramping up the device VCCP before VCCI is recommended to prevent SDA from potentially being stuck LOW.”

Our question is the following. Could you please give me your reply

Q. Is this sentence only difference point between new and old version? (Except document layouts)

your reply would be much appreciated.

Best regards,
Kazuya.

over 1 year ago

0 Tyler Townsend over 1 year ago

TI__Mastermind 23843 points

Kazuya,

Kazuya Nakai59 said:
Q. Is this sentence only difference point between new and old version? (Except document layouts)

Yes!

Kazuya Nakai59 said:
”Ramping up the device VCCP before VCCI is recommended to prevent SDA from potentially being stuck LOW.”

This is the only change that was made between the two revisions that you listed.

Regards,

Tyler

0 Kazuya Nakai59 over 1 year ago in reply to Tyler Townsend

Guru 20130 points

Hello Tyler,

Thank you very much for your reply.
Could I ask you an additional question?

Q. Is it no problem when VCCP and VCCI are same node (VCCP and VCCI are powered up at same timing)?

Thank you again and best regards,
Kazuya.

0 Tyler Townsend over 1 year ago in reply to Kazuya Nakai59

TI__Mastermind 23843 points

Hello Kazuya,

This phenomenon was only seen when VCCI was powered up first before VCCP. When powering VCCP and VCCI at the same time, this event should not occur, and SDA should not get stuck LOW.

Even if the issue does occur, per difference in cap loading on VCCI vs. VCCP, the SDA stuck LOW condition generally resolves itself after both sides are up.

Regards,

Tyler

0 Kazuya Nakai59 over 1 year ago in reply to Tyler Townsend

Guru 20130 points

Hello Tyler,

Thank you very much for your reply.
Could I ask you an additional question as the follow?

Q. You wrote "the SDA stuck LOW condition generally resolves itself after both sides are up.".
Can this be applied for the case that VCCI is powered up before VCCP?
Or in the power up order case, is the SDA stuck LOW condition kept even if both sides are powered up?

Thank you again and best regards,
Kazuya.

0 Tyler Townsend over 1 year ago in reply to Kazuya Nakai59

TI__Mastermind 23843 points

Hi Kazuya,

SDA can potentially be stuck LOW if VCCI is powered up before VCCP. Powering up VCCP after VCCI generally fixes the stuck SDA issue. Best practice is to power up VCCP, then power up VCCI.

Regards,

Tyler

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TCA6408A: Question about difference between TCA6408A datasheet version SCPS192D and SCPS192E.