Pin Diode Switch Ic

Connecting the switch driver control circuit to a pin diode such that it can turn diodes on and off by applying a forward or reverse bias is a challenging task.

Pin diode switch ic.

The wide intrinsic region is in contrast to an ordinary p n diode the wide intrinsic region makes the pin diode an inferior rectifier one typical. Thus a pin diode is a dc controlled high frequency resistor and if no dc current is present the diode is just like an open circuit. A pin diode is a diode with a wide undoped intrinsic semiconductor region between a p type semiconductor and an n type semiconductor region. What is the frequency range of the pin diode as an rf switch.

The bias circuit typically uses a low pass filter between the rf circuit and the switch driver. Signal losses at the closed diode is negligible. The pin diode switch can be used for antennas with impedances of from 50 ω up to 75 ω. A diode alone is not a complete and useful switch as it is only the core switching element.

Figure 5 shows a single pole double throw spdt rf switch and its bias circuit. The signal to noise ration of the receiver deteriorates somewhat up to 1 db. The operated diodes block the disconnected antennas by about 30 db. Chapter 2 the common pin diode switch configurations are presented followed by sections comparing those features of pin diode switch designs for unique to high power microwave switches and high power lower frequency rf band switches.

At a minimum an rf switch based on pin diodes needs a dc blocking capacitor to prevent the dc bias current from reaching the rf output and an rf choke to provide a path for the dc bias current to return while blocking the rf signal. Rf switch with pin diodes circuit diagram. The p type and n type regions are typically heavily doped because they are used for ohmic contacts.