Datasheets

The UM4000 and UM4900 series features high power PIN diodes with long carrier lifetimes and thick I-regions. They are especially suitable for use in low distortion switches and attenuators, in HF through S band frequencies. While both series are electrically equivalent, the UM4900 series have higher power ratings due to a shorter thermal path between the chip and package. High charge storage and long carrier lifetime enable high RF levels to be controlled with relatively low bias current. Similarly, peak RF voltages can be handled well in excess of applied reverse bias voltage.

These series of PIN diodes are designed for applications requiring small package size and moderate average power handling capability. The low capacitance of the UM6000 and UM6600 allows them to be used as series switching elements to 1 GHz.The low resistance of the UM6200 is useful in applications where forward bias current must be minimized. Because of its thick I-region width and long lifetime the UM6000 and UM6600 have been used in distortion sensitive and high peak power applications, including receiver protectors, TACN, and IFF equipment. Their low capacitance allows them to be useful as attenuator diodes at frequencies greater than 1 GHz. The UM6200 has been used successfully in switches in which low insertion loss at low bias current is required. The “A” style package for this series is the smallest Microsemi POWER PIN diode package. It has been used successfully in many microwave applications using coaxial, microstrip, and stripline techniques at frequencies beyond XBand. The “B” and “E” style leaded packages offer the highest available power dissipation for a package this small. They have been used extensively as series switch elements in microstrip circuits. The “C” style package duplicates the physical outline available in conventional ceramic-metal packages but incorporates the many reliability advantages of the Microsemi construction.

Microsemi offers a series of PIN diodes specifically designed and characterized for solid state antenna switches in commercial two-way radios. Antenna switches using the UM9401 and UM9415 series PIN diodes provide high isolation, low loss and low distortion characteristics formerly possible only with electromechanical relay type switches. The UM9401 and the UM9402 diodes can handle 100 W of transmitter power, while the UM9415 will handle over 1000 W. The extensive characterization of these PIN diodes in antenna switch applications has resulted in guaranteed low distortion specifications under transmit and receive conditions. These diodes also feature low forward bias resistance and high zero bias impedance which are required for low loss, high isolation and wide bandwidth antenna switch performance. For RoHS compliant devices, use the UMX prefix. (IE: UMX9415)

The UM9441 is an axially leaded device constructed by metallurgically bonding the PIN chip in between two molybdenum refractory pins that are typically 0.125 inches in diameter and 0.050 inches long. Hyper-pure glass is then fused over this bond to form a void less seal. Leads are then brazed to ends of molybdenum pins. This results in a high-reliability package using materials so well thermally matched that the UM9441 can withstand temperature shock or cycling from -196 oC to +300 oC. Experiments on devices of the UM9441 design show no degradation in gamma sensitivity resulting from a total dose of 1014 neutrons/cm2 of 1 MeV equivalent.

The UM9989 diode series was designed to protect MRI receivers from high RF energy fields including long RF pulses and RF spike pulses present in most MRI machines. The UM9989 acts as a passive protector (limiter) for the MRI receiver. No forward bias voltage is required to turn on the diode. It is self-biased by the RF transmitter pulse power. A switch driver is not needed for this receiver protection application. Receiver protector diodes appear directly across the input port of the receiver. They are connected in anti-parallel pairs to limit the RF carrier excursion in both polarities. They must, therefore, exhibit extremely low insertion loss, both in the “on” state (high power present) and the “off” state (receiver power present) so as not to decrease the receiver’s sensitivity. The UM9989 diodes are available in two package configurations for flexibility in design.

The UMX5601TM PIN diode series was designed to provide ultra low magnetic PIN diodes for in bore surface coil applications associated with higher field strength (3T and greater) MR scanners. These PIN diodes produce the minimum artifacts (magnetic field distortions) available in the industry, today. The diodes have been tested in magnetic fields of ±7 Tesla. The UMX5601 PIN diodes have a magnetic moment at 7 T of 4E-8 (J/T). The diodes are offered in a surface mount package. The SM package utilizes a round end cap to mark the anode. The cathode is square. The fully passivated PIN diode chip is full face metallurgically bonded to shortened high conductive pins for lower thermal and electrical resistances. The PIN diodes feature low forward bias resistance and high zero bias impedance. The UMX5601 PIN diodes are characterized at 64, 128, and 300 MHz. The UMX5601SM meets RoHS requirements per EU Directive 2002/95/EC.