What is the option of LP (LF) all about in the EPIC oscillator list?

I assume it's in regard to low power and the LF series of chips.

Do you check this when programming these? (mandatory?)

I have a 16LF628a that I've just been choosing "XT" with....but there is some erratic behavior. (Circuit works fine with 16F628a).

It's a battery operated IRED xmtr (2 aaa cells)...sometimes when I pick it up to test it....it's dead until I do a hard reboot.


Thanks.