VRRM is the maximum allowable repetitive instantaneous value of the diode's reverse voltage. These transients are the result of circuit and diode properties and are somewhat under the con- trol of the system designer. The key word is “repetitive.”
How is a diode rated?
Maximum DC reverse voltage = VR or VDC, the maximum amount of voltage the diode can withstand in reverse-bias mode on a continual basis. Ideally, this figure would be infinite. Maximum forward voltage = VF, usually specified at the diode's rated forward current.
What does the PIV rating on a diode mean?
For rectifier applications, peak inverse voltage (PIV) or peak reverse voltage (PRV) is the maximum value of reverse voltage which occurs at the peak of the input cycle when the diode is reverse-biased. The portion of the sinusoidal waveform which repeats or duplicates itself is known as the cycle.