Philip Pemberton wrote:

>=20
> I'm currently using four gates of the 74HCT04 and a 74LS86 XOR to form a
> transition detector. The four inverters delay the input signal, and both
> the input signal and delayed signal are fed into the XOR. Unfortunately
> the PLL won't lock onto the XOR's output... probably because it only
> just hits 3V out, and has a pulse width of about 20ns.
>

How about using 'slower' inverters (or slugging with some extra pF) then=20
put an HCT04 after the LS86 to give a better voltage swing?

George Smith
--=20
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