BQ76PL455A-Q1: BQ76PL455A - configuration if Fault Line is unused

Josef Warta

Part Number: BQ76PL455A-Q1

Hello Team, to optimize cost on a 455 solution is following configuration for unused FAULT line possible:

Is it possible to connect FAULTL+ and FAULTH+ with 10kOhm to 5.3V?
FAULTL- and FAULTH+ will be connected with 10kOhm to GND.

Any concerns on this?

Many Thanks

Josef

over 6 years ago

0 Andy Li55 over 6 years ago

TI__Intellectual 2520 points

Hello Josef,

Thanks for choosing TI's part.

You schematic looks fine, but it is better to be use VDIG.

You can leave them unconnected if not used.

Andy

0 Josef Warta over 6 years ago in reply to Andy Li55

TI__Expert 4300 points

Hello Andy,
many thanks for your quick answer.
Challenge is that it should be a quick design change and the closest connection is to 5V3. According datasheet pin is spec'd up to 6V.
And with 10k resistor it should reduce the leakage current also to a safe level.

Means 'leave unconnected' that open state is ok for all FAULT pins?
Thanks
Josef

0 Andy Li55 over 6 years ago in reply to Josef Warta

TI__Intellectual 2520 points

Hello Josef,

As Datasheet mention, we can leave them unconnected, which means float.

Andy

0 Jochen Gans over 6 years ago in reply to Andy Li55

Prodigy 20 points

Hello Andy,

my name is Jochen Gans and I am development engineer at Preh. The 5.3V is the VDIG voltage. That means 5.3V from regulator are connected to VIO (Pin41), VDIG (Pin34). In the past we connected not used Pins to GND (COMM- or FAULT-) or to V5VAO (COMM+ or FAULT+) via 10k resistor. If it don't make a difference to use V5VAO or VDIG (5,3V) then it is ok.

Jochen

0 Jochen Gans over 6 years ago in reply to Andy Li55

Prodigy 20 points

Hello Andy,

but a connection to VDIG or VIO for FAULT+ and GND for FAULT- is also possible?

Jochen

0 Roger Hwang over 6 years ago in reply to Jochen Gans

TI__Genius 10785 points

HI Jochen,

The diff is that VIO is disable in shutdown mode.
V5VAO is always ON.

So, I don't recommend to connect them to VIO.
I think best is float(unconnect) unused pins.

roger

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BQ76PL455A-Q1: BQ76PL455A - configuration if Fault Line is unused