This circuit was born from an application that required an input signal to be precisely clamped to less than 2.5 V, while operating on a 2.5 V supply (actually a reference) with a maximum output of 4 ...

And here it is, modelled using LTSpice. It is the same circuit as the classic simple precision rectifier (set to pass the negative half-sine), but with the non-inverting input of the op-amp connected ...

Voltage clamps for protecting low-voltage dc circuits require a new approach to circuit design. Many commonly used voltage clamps were built for systems of 5 V or higher, but lower-voltage systems ...