I need my AVR to output two separate +/- 5v analogue outputs. (to control two galvanometers, high impedance, low current.)
I've decided to use an SPI device, as it will be easier to interface to. So I searched on Google for a dual channel 8bit SPI DAC, and this one popped up in the top 3 : "Analog Devices AD5429"
So, I can interface the DAC to the AVR. But I'm struggling on the external opamp circuit I'd need to take the output from the DAC to +/- 5v. I have a +/- 15v supply.
Luckily for me, the data sheet has a detailed schematic of their evaluation board, which I think is very close to what I need. Is it as easy as changing the supply to the opamp to +/- 5 v ? (changes marked on the schematic in red rings) (plus I know I need to turn the polarised capacitors around accordingly), or have I over simplified the problem ?
On page 16 the data sheet says "In some applications, it may be necessary to generate full 4-quadrant multiplying operation or a bipolar output swing. This can easily be accomplished by using another external amplifier and three external resistors, as shown in Figure 39"
I think I need a "bipolar output swing" ? Which means I need two opamps on each output ? right ?
Help ? I'm a bit lost with opamps.