I've been looking into precision ground reference circuits to form ±5V rails from a 10V supply for a project I'm working on, and noticed that current feedback (CFB) op-amps have some desirable characteristics (primarily high output current and slew rate). Since I will be using it as a return path for multiple filters and decoupling capacitors, it needs to have a high output current and fast settling time. However, I also need keep the DC level stable across a range of temperatures and under varying loading conditions.
I like the dual-feedback design below that a voltage feedback op-amp, but I also have a few concerns:
- The suggested precision op-amp has a low slew rate. This could be problematic since I am expecting (unavoidable) step changes at the output.
- With the series resistor, I'm afraid that the op-amp will saturate before it can source or sink sufficient current.
- Can I safely route the inverting input of a CFB to a distant part of the board (as a Kelvin connection)?
- Assuming that I can guarantee stability under capacitive loading conditions, am I likely to run into DC drift issues (possibly due to self-heating)? I don't care about the initial DC offset as long as it is very stable.
- After setting the feedback resistor, can I still expect to get a high slew rate?