UM9604

The UM9601-UM9608 series of PIN diodes was developed for shunt mount applications in microstrip circuits. Good switch performance is demonstrated at frequencies from UHF to 4 GHz and higher. This performance is achieved using discrete low inductance Microsemi PIN diodes assembled with special hardware to permit good electrical and mechanical compatibility with microstrip transmission lines.

Design information is presented for preparation of microstrip circuit boards to accommodate these PIN diodes. A detailed design for a 900 MHz quarter-wave antenna switch is given. This switch which employs a low cost UM9401 axial leaded PIN diode in conjunction with a UM9601 performs with 30 dB receiver isolation over a 100 MHz bandwidth and with a transmitter insertion loss of less than 0.4 dB. This switch can safely handle transmitter power levels up to 100 watts at infinite SWR.

The Microsemi UM9601 series PIN diodes are constructed using a fused-in-glass which results in a highly reliable, hermetic package. The process utilizes symmetrical, full faced metallurgical bonds to both surfaces of the silicon chip. This construction greatly minimizes the normal parasitic inductance and capacitance found in conventional glass or ceramic packaged diodes which employ straps, springs, or whiskers.

The use of discrete UM9601-UM9608 diodes greatly minimizes handling problems commonly associated with passivated PIN diode chips while maintaining good microwave performance. In addition the power handling capability of the UM9601-UM9608 series is considerably higher than PIN diode chips can provide.

Environmentally, the UM9601-9608 series PIN diodes can withstand thermal cycling from -195 to +300 and exceed all military environmental specifications for shock, vibration, acceleration,and moisture.