I have a PIC16F628a that I want to run off a 3 Volt supply (3V 2032 lithium battery). The PIC works as expected at 5 Volts supply, but when I drop the supply below 4.5 Volts the PIC stops working. The data sheets say this PIC should operate on as low as 2.0 Volts DC supply.

Is there something I am missing??

Help!

Thanks, Russ