Where can I get them? The AD5206 only comes in 10k and 100k but the project I'll doing probably needs other values (250k and 500k), what where can I get other chips with this values?
If you live in the U.S. it looks like [u]Digi-Key[/u] has selection. Or, you could probably re-design you circuit to use a different value, or possibly re-design the circuit to use something other than a digital pot.
So what do I need to look for a pot that I can use like the AD5206 but with other KOhm values? there are just too much specs on them that I don't understand.
Why do you need such values? Perhaps there's a way to work round this if we know the requirements...
First, Digi-Key has a large number of digital potentiometers.
Second, you often need to set a particular voltage, or amount of feedback, which can easily be done with something like an opamp and the programmable pot, instead of a programmable pot of a very particular value.
Third, you can hook the pots in series.
Fourth, you can extend the range of existing pots by shorting or not a series resistor. For example, if you have a 500 kOhm pot, you can extend it to 1 MOhm by putting it in series with a 500 kOhm resistor, and shunt that resistor in parallel with a low-Rdson MOSFET transistor. Basically, you're adding another, higher valued, bit to the input control.
jwatte:
First, Digi-Key has a large number of digital potentiometers.
Second, you often need to set a particular voltage, or amount of feedback, which can easily be done with something like an opamp and the programmable pot, instead of a programmable pot of a very particular value.
Third, you can hook the pots in series.
Fourth, you can extend the range of existing pots by shorting or not a series resistor. For example, if you have a 500 kOhm pot, you can extend it to 1 MOhm by putting it in series with a 500 kOhm resistor, and shunt that resistor in parallel with a low-Rdson MOSFET transistor. Basically, you're adding another, higher valued, bit to the input control.
You could do that, but I'd go for a much higher Rds(on) MOSFET with as low a gate capacitance as possible to reduce switching transients that couple through to the signal.
Yes, that's probably the better tradeoff.
MarkT:
Why do you need such values?
Because since its an audio project the value of them affect the final audio signal that will come out, so I need to use the same value.