TPS65218 / to reset FSEAL bit

K.Yaita

Hi Team,

The datasheet shows as the following to reset FSEAL bit.
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(datasheet page.42)
Coin-cell battery and main supply must be disconnected from the IC to reset the FSEAL bit again.
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Could you tell me the threshold voltage of coin-cell battery and main supply to reset FSEAL bit?
Does it need to voltage to 0V each?

My customer confirmed FSEAL bit didn't be reset when discharged as much as 0.7V each.

Best Regards,
Yaita / Japan disty

over 10 years ago

0 K.Yaita over 10 years ago

Guru 29720 points

May I have your comment please?
My customer would like to konw it in a hurry.

Best Regards,
Yaita

0 Michael Green over 10 years ago in reply to K.Yaita

TI__Genius 16870 points

Hi,

I believe 0.7V would be sufficient of pull down to reset the FSEAL bit domain but, I am having this verified before we close this out.

0 Paul Kundmueller over 10 years ago in reply to Michael Green

TI__Intellectual 1990 points

Yaita-san,

Sorry for the late reply. I would like to follow up on Michael's response. 0.7V should be sufficient but to ensure a proper reset of the FSEAL bit, both the coin cell (CC) and IN_BIAS voltages should be forced to less than 0.2V. Please let me know if you have any questions. Thanks for the post!

Best Regards,

Paul Kundmueller

If this response answers your question in a satisfactory way please check the the Verify Answer button below.

0 Michael Green over 10 years ago in reply to Michael Green

TI__Genius 16870 points

HI,

After discussing with the designer, I realized that I was wrong. In-order to reset the FSEAL bit you will need to pull the backup battery to 0V would as close as possible, like 100 - 200 mV or so. This is well below the recommended operating minimum for the backup battery at 2.2 V. In-order for the DCDC5 & 6 regulation you should keep the backup battery above 2.2 V.

0 K.Yaita over 10 years ago in reply to Michael Green

Guru 29720 points

Hi Paul-san, Michael-san,

I understood.
I really appreciate for your support.

Best Regards,
Yaita

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TPS65218 / to reset FSEAL bit