PCA9306-Q1: EN Pull-up Inquiry

Andy Snawerdt

Part Number: PCA9306-Q1

Hi Team,

This devices datasheet recommends a weak 200kΩ pull-up for the EN signal. Is there any reason why this pull-up needs to be so weak? Could we instead use a stronger pull-up, and if so, is there a minimum allowable value that can be used for this resistor?

My assumption is that this just comes down to how much power you're willing to consume, correct?

Regards,

Andy

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 323920 points

This resistor is not a pull-up; it limits the current that flows into VREF2 and out of VREF1, and drops the voltage at the EN pin to the proper gate bias voltage. (See [FAQ] How do the LSF translators work?)

You can use a lower value, but the VREF1 power supply must be able to sink the current.

0 Danny Bacic over 4 years ago

TI__Mastermind 26836 points

Andy,

Clemens is correct - this is not simply a pull-up resistor on this pin. This is why VREF2 and EN are directly connected to each other in the device's application diagram.

Best,

Danny

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PCA9306-Q1: EN Pull-up Inquiry