BQ40Z80: How should we connect and set the unused Pin17?

Klaus

Expert 1431 points

Part Number: BQ40Z80

Hi Ti Experts,

we have developed a BMS with the bq40z80. It is a 7S1P Lion application.

We do not use the Pin17 of the bq.

1) How should I connect it?

2) How should I set the DataFlash?

In the following training viedeo:

I have seen that an unused PRES and SHUTDOWN Pin should to leave open:

In the datasheet of the bq40z80 I found this:

This I did in the schematic:

In the TechRef I found this:

This is my corresponding setting of the dataflash:

3) What should I do? Connect do VSS or leave floting?

Thanks for helping us.

Klaus

over 4 years ago

0 Wyatt Keller over 4 years ago

TI__Guru** 105590 points

Hello Klaus,

The configuration you have should work correctly, are you having issues with the operation of pin17?

Sincerely,

Wyatt Keller

0 Klaus over 4 years ago in reply to Wyatt Keller

Expert 1431 points

Hi Wyatt,

thanks for your answer.

until now we have no issues with pin17.

I am asking this because maybe we want to change the layout a little bit and than I could change the connection of pin 17 from ground to floating.

I do not know what to do. The training viedeo says floating the pin and the datasheet says connect to VSS. What is the right way to do?

Thanks for helping us.

Klaus

0 Klaus over 4 years ago in reply to Klaus

Expert 1431 points

Hi Wyatt,

are there any news?

Thanks,

Klaus

0 Wyatt Keller over 4 years ago in reply to Klaus

TI__Guru** 105590 points

Hello Klaus,

You can configure the gauge for either way, if the firmware isn't looking at the pin (you're not using any of the pins functionality) it can be left floating or grounded.

Sincerely,

Wyatt Keller

0 Klaus over 4 years ago in reply to Wyatt Keller

Expert 1431 points

Hi Wyatt,

ok thanks.

Then I leave the connections connected to GND.

Klaus.

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BQ40Z80: How should we connect and set the unused Pin17?