> Probably you should use to PIC16C63JW power supply at range 4.0 - 6.0 v
> JW device don't like power below 4.0v, IMHO (by practical experiments
> with 63/65JW)
>
> WBR Dmitry.
> P.S. When I was start my experiments with JW devices PIC16C63JW/04 was
> stable running
> at power supply 4.0v . After ~200 cycles of erasing this device starting
> to function
> only at power supply 4.5v or higher ;(

Failure to function at low voltages is often a consequence of insufficient
erasure.  Microchip requires that any "certified production" programmer read
a part at its lowest operating voltage (to ensure proper erasure) and at its
highest operating voltage (to ensure suitable programming margin).  If your
programmer only supplies +5.0 volts VDD (I think that's the case with the
PicStart) then it's possible that inadequately erased memory cells will read
"0" at, e.g., 4.0 volts VDD (not erased) and yet read "1" at 5.0 volts VDD
(causing the programmer to THINK they're erased).

IMHO, if you are going to use chips in any less-than-five-volts application,
it is absolutely essential that you use a programmer that can supply the lower
VDD.  Because the lower voltage is only needed for verification rather than
programming, your supply won't need to supply much current at that voltage and
a pair of resistors should work adequately if you have a reasonable bypass cap
on VDD.  In fact, using such a supply can reduce the likelihood of the prog-
rammer accidentally frying, e.g., a mis-inserted chip because the current will
be limitted while the chip is blank-checked; if the chip is mis-inserted the
blank-check will fail and the high-current programming VDD will not be enabled.