[sdiy] CV input op-amp circuit

[Tony Allgood]

 > It can only absorb the clamping current either momentarily with some 
big decoupling capacitors, or in the steady-state if there is sufficient 
load on the supply.

I have sometimes used a pair of Schottky diodes to the rails on the 
input, along with a suitably rated zener diode across the power rail 
itself. eg. 5V6 on the +5V rail. I reckon if there's enough current 
delivered through the input series resistor to raise the power supply 
voltage via the upwards facing Schottky, the zener should protect any 
devices connected to that rail.

Tony