[sdiy] Digital Pots

[Jeff Farr]

SO, while scouring the net for a way to connect a MIDIBox SEQ to a 808
clone so that all the parameters are digitally controlled I've come
across a series of IC's at analog devices and maxim-ic called digital
potentiometers.  There is a large variety of them in many different
resolutions, of specific interest are the ones with 127 possible
values.  Has anybody tried to use these as an in between from encoders
+ digital interface to regular VC circuits?  Some of them are 2
terminal and are listed as , but others have three which would seem
ideal.

Quote from site:
"The AD5247 provides a compact 2 mm x 2.1 mm packaged solution for 128
position adjustment applications.

This device performs the same electronic adjustment function as a
mechanical potentiometer or a variable resistor. The low temperature
coefficient makes this device ideal for high accuracy and stability
variable resistance adjustments. "

http://www.analog.com/en/subCat/0,2879,761%255F797%255F0%255F%255F0%255F,00.html

http://www.analog.com/en/prod/0,,761_797_AD7376%2C00.html

Seems with such a selection there should be at least one that will
work.  There aren't alot of available resistance values, but if I'm
not mistaken I can place it in parallel with a regular resistor to
achieve the desired range through 1/Rt = 1/R1 + 1/R2 etc.