[sdiy] Hi frequency VC clock

[Steve Lenham]

On 21/06/2017 12:25, Tom Wiltshire wrote:
> The reasons are pretty straightforward:
>
> 1) Cheap
> 2) Available
> 3) VCO to 10+MHz.
>
> Find me another chip that fulfils the above criteria and I'll use it! ;)

74LS624/628/629?

Venerable but still in production, which perhaps says something.
Cheap-ish (though not as cheap as a 4046).
Good for 25MHz if you want but can go low too.
Still intended as PLL VCOs (so linear) but the OP wanted something to 
act as a sweepable clock generator, not an expo VCO. A device from this 
family (74S124, also still available but loves current) is used for that 
very purpose in the original Lexicon Prime Time delay, with triangle 
wave modulation.

Cheers,

Steve L.
Benden Sound Technology