The P-I-N diode has a relatively large stored charge adrift in a thick intrinsic region.

At higher frequencies, there is not enough time to sweep the charge from the drift region, so the diode never turns off.

For a given semiconductor material, on-state impedance, and minimum usable RF frequency, the reverse recovery time is fixed.

This property can be exploited; one variety of P-I-N diode, the step recovery diode, exploits the abrupt impedance change at the end of the reverse recovery to create a narrow impulse waveform useful for frequency multiplication with high multiples.

[citation needed] The high-frequency resistance is inversely proportional to the DC bias current through the diode.

At high frequencies, the PIN diode appears as a resistor whose resistance is an inverse function of its forward current.

Consequently, PIN diode can be used in some variable attenuator designs as amplitude modulators or output leveling circuits.

PIN diodes are sometimes designed for use as input protection devices for high-frequency test probes and other circuits.

Unlike a rectifier diode, it does not present a nonlinear resistance at RF frequencies, which would give rise to harmonics and intermodulation products.

The latter may be combined with an isolator, a device containing a circulator which uses a permanent magnetic field to break reciprocity and a resistive load to separate and terminate the backward traveling wave.

When used as a shunt limiter the PIN diode impedance is low over the entire RF cycle, unlike paired rectifier diodes that would swing from a high resistance to a low resistance during each RF cycle clamping the waveform and not reflecting it as completely.

Under reverse bias, the diode ordinarily does not conduct (save a small dark current or Is leakage).

When a photon of sufficient energy enters the depletion region of the diode, it creates an electron-hole pair.

This wider depletion width enables electron-hole pair generation deep within the device, which increases the quantum efficiency of the cell.

Commercially available PIN photodiodes have quantum efficiencies above 80-90% in the telecom wavelength range (~1500 nm), and are typically made of germanium or InGaAs.

They feature fast response times (higher than their p-n counterparts), running into several tens of gigahertz,[5] making them ideal for high speed optical telecommunication applications.

[7] SFH203 and BPW34 are cheap general purpose PIN diodes in 5 mm clear plastic cases with bandwidths over 100 MHz.