Pin Diode Switching Speed

The pin diode is a special diode which can be configured as an rf switch.

Pin diode switching speed. However because it merges both the rf signal path and the dc bias to the same connection point it requires careful understanding and consideration when assessing whether to use series shunt or combined. At 320 mhz the capacitive reactance of 1 pf is 497 ohms. For example the capacitance of an off state discrete pin diode might be 1 pf. Pin diode cross section.

Our pin diode spdt switch designs feature excellent insertion loss as low as 1 2 db isolation levels up to 80 db and fast switching speed levels as low. Ag318 comparison of gallium arsenide and silicon pin diodes for high speed microwave switches an3022 establishing the minimum reverse bias for a pin diode in a high power switch an3008 using the dr65 0109 dr65 0003 replacement part to drive spdt pin switches. Small physical size compared to a wavelength high switching speed and low package parasitic reactances make it an ideal component for use in miniature broadband rf signal control circuits. The pin diode is an apparently simple passive device used in a variety of switching designs due to its speed and isolation potential.

The lifetime of pin diodes is determined by design and is usually based on the desired switching speed. These diodes are passivated with silicon dioxide for high stability and reliability and have been proven by thousands of device hours in high reliability systems. For a value of 100 nsec fc is 1 6 mhz. The primary pin properties that influence switching speed may be ex plained as follows.

This is indeed a factor but equally. The ceramic packaged gc4200 series are high speed cathode base pin diodes made with high resistivity epitaxial silicon material. Thus the diode can be simply visualized as follows. Switching speed model for cw applications the value of thermal resistance the switching speed in any application depends on the driver circuit as well as the pin diode.

It has a wide undoped intrinsic semiconductor region i sandwiched between a p type semiconductor p and an n type semiconductor region n hence the pin designation. Silicon flip chip pin diode. Have faster switching speed. A pin diode switch can switch much more quickly e g 1 microsecond although at lower rf frequencies it isn t reasonable to expect switching times in the same order of magnitude as the rf period.

There is a common misconception that carrier lifetime τ is the only parameter that determines the lowest frequency of operation and the distortion produced. A pin diode has two switching speeds from forward bias. Pasternack offers many models of single pole double throw spdt pin diode switches covering frequency bands from 10 mhz to 67 ghz. At frequencies well below fc the pin diode behaves as an ordinary pn junction.