PCA9306: Pull up resistance in REF2 pin of PCA9306DC1

Jim Huang1

Prodigy 20 points

Part Number: PCA9306

HI Sir:

Is it necessary to have a pull-up resistance on REF2 pin ?? (200K ohm in datasheet). What does it happened without it ?

over 3 years ago

0 Tyler Townsend over 3 years ago

TI__Mastermind 47328 points

HI Jim,

Having a 200k ohm pullup on REF2 pin to VCC2 ensures current limit between Vref2 and Vref1 across the passFET. If 200k ohm resistor is not implemented, and Vref2 >> Vref1 while EN is HIGH, you see a low impedance path across the passFET and could potential damage the FET if you exceed the absolute maximum continuous current draw.

See the comparisons between figures 8-1 and 8-2.

Regards,

Tyler