[sdiy] DAC for MIDI2CV

[Seb Francis]

Hi Again,

Thanks everyone for your input on my VCA tempco question.  The VCA is now working beautifully, and passes the "hairdryer" test using a single-opamp and tempco potential divider input stage ;-)


I am back to the design of my MIDI2CV converter, and the thing that is causing me the most trouble is finding the right DAC for not too much money.  I want at least 14bit +-1LSB, but 16bit would also be fine and they seem much more common.  I want to add things like pitch bend, and have LFOs in software, so high resolution is important.

But, I'm having real trouble in UK finding a reasonably priced one (e.g. <£20) which has low integral linearity error.  Having spent a lot of time looking through datasheets, it seems accurate DACs designed for control applications are generally expensive (it also needs to settle reasonably fast because it's running 16 CV outs).

However, I have seem quite a few so called "PCM Audio" DACs (e.g. BB PCM56, AD AD1856N), and these _seem_ cheap and well spec'ed in comparison with control DACs.  But none of the datasheets quote the integral linearity error - they give only the differential linearity error and THD.  Am I to assume that the integral linearity error is quite high on these types of DAC, and they are not suitable for pitch control applications?  I'm getting a headache from reading all these datasheets!

If someone can point me to a suitable 14 or 16 bit serial input DAC (available in UK) that would be perfect, but failing that a general answer about the suitability of "audio" DACs would be much appreciated.

Thanks in advance,
Seb