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There's a couple stumbling blocks I've run into when looking at digital pots... First off, they're usually only rated to a couple mA, so at 3-5v they're only capable of handling something like a few hundredths of a watt, whereas for a laser driver you're going to need it to be able to handle at least 1/2W. My half watt potentiometers heat up quite a bit when working with 400+mA, I've done the calculation before and they're dissipating something like 490mW of heat.
The second problem I've found is that digital pots are usually in the 10k-100k ohm range, where we really need the 1ohm to 10ohm range.. The digipots you linked to are 10 ohm to 10k ohm, so even at their lowest setting they're 10 ohms +- 20%, so the highest power you're going to be able to set them to is 125mA +-20%.
Oh, and the problem with simply using analog pots is that if their wiper leaves the track even for a millisecond, your output will jump to 1500mA.
The second problem I've found is that digital pots are usually in the 10k-100k ohm range, where we really need the 1ohm to 10ohm range.. The digipots you linked to are 10 ohm to 10k ohm, so even at their lowest setting they're 10 ohms +- 20%, so the highest power you're going to be able to set them to is 125mA +-20%.
Oh, and the problem with simply using analog pots is that if their wiper leaves the track even for a millisecond, your output will jump to 1500mA.
