I'm building a voltage supply that uses a DAC to convert a binary string into an analog voltage. The DAC can't source a lot of current, so I'm using unity-gain amplifiers after the DAC output on each channel. I want to make sure that those little unity-gain amplifiers don't get blown up in case the load is suddenly low resistance and draws a bunch of current (my little unity-gain amps can only handle 20 mA).
I was thinking about setting a sense resistor to produce a 0.7V voltage when the current reaches 20 mA, but I'm concerned that I'll be adding some noise to my output voltage (I'm going for low noise).
Is this the right way to go? Is there a discrete IC that is meant for this purpose that I should be using?