[sdiy] Other dedicated V-to-freq chips

[Aaron Lanterman]

Ian's recent experiences with the LM331 made me wonder if some other  
dedicated V-to-freq chips were worthy of exploration?

I have datasheets for the following on my http://users.ece.gatech.edu/~lanterma/sdiy/datasheets 
  page:

• Analog Devices AD537 ($13.74/1 Digi-Key) (may be overkill for synth  
work)
• Analog Devices AD654
• Analog Devices ADVCF32
• National Semiconductor LM231/LM331 ($6.38/1 LM231, $2.8/1 LM331 Digi- 
Key)
• Fairchild KA331
• Exar XR2206 ($3.59/1 Jameco)
• Exar XR2209, Radio Shack Ap Note
• Exar XR4151 (used in the Rhodes Chroma!) ($1.29/1 Jameco)
• Microchip TC9400/9401/9402 ($6.881/1 TC9400, $7.01/60 TC9401,  
$3.25/1 TC9402 Digi-Key)

The XR4151 is the only I know of to turn up in a commercial synth.

Some of the above chips appear in posts in the SDIY archives, but the  
reports tend not to be highly enthusiastic - but most of them have  
probably not been subject to the Fritz treatment. I think Ian could  
make an in-tune-for-10-octaves zero-heat-drift VCO out of a rubber  
band, a box of legos, and a caffinated ferret.

- Aaron