How to protect input against both ESD and reverse polarity?

If the idea is to protect the diode, one could put a TVS diode with a voltage much higher than anything that might be put on the inputs, like something that would clamp more than 40 or 100V. There are many TVS diodes built specifically for handling ESD and have much higher 'knee' voltages. The diode would not turn on if the polarity were reversed, but would turn on during an ESD event. This would protect the reverse polarity diode.

schematic

simulate this circuit – Schematic created using CircuitLab

Another way that less lossy would to use a pmosfet for reverse polarity protection.

schematic

simulate this circuit


To prevent the TVS will be damaged due to reverse polarity, just add another TVS in anti-series.

schematic

simulate this circuit – Schematic created using CircuitLab

D1 should be rated with respect to the maximum correct applied voltage.
D3 should be rated with respect to the maximum (expected) reversed applied voltage.
(In OP "the reversed input could be -5V", so, D1 and D3 can be the same components).

  • In case of ESD, one TVS will be forward biased and the other TVS will clamp.
  • In case of reverse polarity D3 will protect D1.
    D2 will protect the rest of the circuit.