PCA9306: EN Control

Liu Yang

Expert 5915 points

Part Number: PCA9306

Hi Team,

I am thinking of controlling EN externally.

Currently I am connecting the FPGA signal directly, is that correct?

Beat Regards,
Tom Liu

over 1 year ago

+1 Clemens Ladisch over 1 year ago

Guru 243180 points

This is not correct; the signals on side 1 will not be clamped to 1.8 V. There are two possible alternatives:

Configure the FPGA's EN pin as an open-drain output, connect EN also to VREF2, and remove the pull-down.
Change the high level of the FPGA's EN pin to 1.8 V. (You can then leave VREF1/2 open and remove the 200 kΩ resistor.)

0 Liu Yang over 1 year ago in reply to Clemens Ladisch

TI__Expert 5915 points

HI Clemens,

I'm sorry for this late reply.

Coould you check the revised schematic? Thnak you.

Beat Regards,
Tom Liu

+1 Clemens Ladisch over 1 year ago in reply to Liu Yang

Guru 243180 points

Yes, this will work.

(For this open-drain buffer, the power supply does not matter; you can move both the FPGA's EN pin and the buffer to 1.8 V if this would be easier for you.)

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PCA9306: EN Control