Now, with that DAC, we need to somehow get 2 +/-5V differential signals, and then 6 0-5V signals. So what I am wondering, is what would be the best way to get 2 +/-5V differential, and 6 0-5V signals from that DAC chip? We know opamps would be our best bet, but we dont know which opamp would suit us best. Our power supply would be from the USB port, so something that runs on +5V would be good, but if absolutely needed, we can get little DC/DC converters that will give us +/- from the 5V USB
I would suggest you're going to struggle unless you use an external power supply, otherwise you will need to generate a -5V supply from the USB +5V one - and USB can only supply a relatively small current.
The other problem is the +5V/-5V swing requirement, even so called 'rail to rail' opamps don't actually manage it, they just get closer than a normal opamp.
Hi Nigel, yeah, I am a little worried about the power requirements too. The USB port would basically have to power a FTDI USB - Serial interface, that DAC chip, then some sort of amp. The output signals only really need to be low current.
I'm guessing a well selected rail to rail opamp would work, you'd have to read the PDF on a couple to determine what the frequency/slew rate limits are at full rail outputs I really don't know if you'll find anything that will give you a full 50khz rail to rail though.
I don't know what kind of signal you're actually driving but a small transformer might work as well, but you'll lose DC coupling and the frequency would have to be fixed or it'd become non-linear.