PCA9306: Connected VREF2 to +3.3V instead of to pin 8

Tom Lowdermilk

Part Number: PCA9306

I messed up and instead of connecting VREF2 to pin 8 of the chip (the Enable pin, which then connects to +3.3V through a 200k Ohm resistor), I connected it directly to +3.3V.

VREF1 is +1.8V and I'm seeing it's Voltage fluctuate at a very low frequency between about +2.2V and +1.8V.

Could this be caused by my screw-up?

over 8 years ago

0 fhoude over 8 years ago

TI__Mastermind 23116 points

Yes, it most definitely is. It also opens you up to potential damage during turn on and off conditions. Can you show me a schematic of how you connected it?

Here is what is internal to the part:

-Francis Houde

0 Tom Lowdermilk over 8 years ago in reply to fhoude

Intellectual 300 points

hello Francis,

Thanks for the quick reply,... much appreciated!

Here's my mistake:

0 Tom Lowdermilk over 8 years ago in reply to Tom Lowdermilk

Intellectual 300 points

hello Francis,

As a follow-on question,... regarding the Normal and Abnormal Setups you showed above, what Voltages can
we expect at VREF1 and EN in each setup?

best regards,

Tom

0 fhoude over 8 years ago in reply to Tom Lowdermilk

TI__Mastermind 23116 points

Hello Tom,
I would expect the voltage to be around 2.5V. I am just going off circuit analysis.
-Francis Houde

Interface

Interface forum

PCA9306: Connected VREF2 to +3.3V instead of to pin 8