vcos, exp conv, etc.

[Michael Lloyd]

While thumbing thru some notes, I found references to a couple of articles that might be of interest (or at least make for good reading for aspiring analog gurus!). 
1. EDN Magazine, May 16, 1985 pp153-164 "Design techniques extend V/F converter performance" (part 1 of 2)
2. EDN Magazine, May 30, 1985 pp239-248 "Refine V/F converter operation with novel design techniques" (part 2 of 2)
These were written by Jim Williams of Linear Technologies, who I think also did the vco circuit in National's "famous" AN299 when he was with them. Not much on exponential converters per se, but more on making wide range VCOs.

Also, I just ran across what I guess to be an update of these articles: AN14 "Designs for high performance voltage to frequency converters" also by Jim Williams. I'd guess this is available from LT's web site. One circuit (p15) is an exponential VCO using the CA3096AE for log and thermal control functions. It claims a drift of 150ppm/degree C and exponential conformity of 0.13% over 10Hz to 20KHz.

And, there's a version of the AN299 circuit on the data sheet for the LT1055/LT1056 BiFET opamp, using the CA3096AE also.

I'm curious, who has better specs: CA3045, CA3046, or CA3096AE?

FYI,
Michael
mlloyd1 at enteract.com 
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