BQ40Z50-R2: DFW Failures

Mulin Chou

Prodigy 175 points

Part Number: BQ40Z50-R2

Tool/software:

Hi,

I have two sample is having DFW fault.

We read back the SREC files from failed IC, please refer attached file.

Please help to check the root caused of DFW?

How to avoid happening?

Thanks a lot.

Mulin

8422.Downloads.zip

4 months ago

0 Alan Frias 4 months ago

TI__Mastermind 25855 points

Hello Mulin,

This is probably an indication that unit is either worn out or damaged flash. This can be potentially fixed by upping the "Valid Update Voltage" but most likely would need to be replaced. I've also reference this e2e trend below for more information.

E2E trend:
https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1106167/bq40z50-r2-dfw-issues

Thank you,
Alan

0 Mulin Chou 4 months ago in reply to Alan Frias

Prodigy 175 points

Hi Alan,

Thanks your feedback.
My pack was 4S2P, fully charge voltage was 4.15V*4=16.6V.
The "Valid Update Voltage" was min stack voltage threshold, please let me know what "Valid Update Voltage" your recommendations.

tks.

Mulin

0 Alan Frias 4 months ago in reply to Mulin Chou

TI__Mastermind 25855 points

Hello Mulin,

According to pervious e2e trends for a similar battery gauge as yours it says a " higher number than 3500mV" so there is no set number and I would recommend increasing it by 500mV intervals regardless I would if it is still buggy or sees glitches than the flash would is worn out.

Reference E2E trend:
https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/878811/bq40z60evm-578-data-flash-wear-out-dfw-is-set-1-how-to-make-the-dfw-bit-reset?tisearch=e2e-sitesearch&keymatch=BQ40Z60EVM-578

Thank you,
Alan

0 Mulin Chou 4 months ago in reply to Alan Frias

Prodigy 175 points

Hi Alan,

My pack was 4S2P, fully charge voltage was 4.15V*4=16.6V.
If the "Valid Update Voltage" change to 16800mV, was the Lifetimes still update?
I had do some test, and let stand for ten hrs, the Lifetimes was not update, was it reght?

tks.

Mulin

+1 Alan Frias 4 months ago in reply to Mulin Chou

TI__Mastermind 25855 points

Hello Mulin,

After discussing with the team although a DFW failure will not show within by updating valid update voltage this is simply a bandage solution since it would still show in real world testing as "buggy". The DFW failure can show up from flashing the device to many times or from an ESD event, the prevent the DFW failure from happening hardware protection for ESD would be recommend.

Mulin Chou said:
If the "Valid Update Voltage" change to 16800mV, was the Lifetimes still update?
I had do some test, and let stand for ten hrs, the Lifetimes was not update, was it reght?

-Which life time parameter are your referencing but upping the valid update voltage would make it less likely for flash updates.

Thank you,
Alan

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BQ40Z50-R2: DFW Failures