BQ76940: Does leaving the ALERT pin floating impact operation and if so, how?

jgeng

Part Number: BQ76940

Tool/software:

Hello,

I am currently looking over a design and the ALERT pin was left floating. I am wondering if this will affect operation and if so what are the possible issues?

Thanks!

3 months ago

0 Arelis Guerrero 3 months ago

TI__Expert 5645 points

Hello,

The ALERT pin could be used as both, input or output to an MCU. As an input the pin has no internal debounce support, and is very sensitive to noise which benefit from a RC filter. This pin also include a weak pull down, to be allow to be driven externally or to pull the active high output signal. Due to this, the datasheet recommends to place an external 500kohm - 1Mohm pull-down resistor from ALERT to VSS at all time, even if unused to avoid the pin to be left floating.

Regards,

Arelis G. Guerrero

0 jgeng 3 months ago in reply to Arelis Guerrero

Prodigy 10 points

Is it possible to receive a false alert if this pin were to be left floating and not connected to the recommended pull-down resistor?

Thanks

+1 Arelis Guerrero 3 months ago in reply to jgeng

TI__Expert 5645 points

Technically yes, if the pin is floating and at any stage is configured as an input, you could triggered a false alert. Again, is highly recommended to not leave this pin floating.

0 jgeng 3 months ago in reply to Arelis Guerrero

Prodigy 10 points

Thank you!

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BQ76940: Does leaving the ALERT pin floating impact operation and if so, how?