Once the circuit is stable, gained up, and the DC errors removed from the design, it is time to consider the AC response. If the circuit is too slow, the output will just hunt between final values and never accurately represent the signal. If the response is too fast, the circuit will ring and overshoot. This is the point at which the value of feedback capacitor, CF, can be tweaked to give optimum response. If the circuit cannot be made fast enough, it is worth putting a reverse bias on the diode, if its inevitable DC error is still acceptable. If that does not work, a faster amplifier is needed or a diode with lower capacitance. The diode may also be reverse biased to reduce its capacitance. Then it is important to test the circuit over temperature to ensure the response is acceptable at all expected conditions.