Pulse-doped GaAs MESFET with Excellent Linearity

• SEI originally developed the sophisticated GaAs metal semiconductor field effect transistor (MESFET) for use in microwave applications, called "Pulse-doped MESFET". The pulse-doped MESFET with a highly doped and thin active layer is quite suitable for low distortion power application because of its intrinsic characteristics of good linearity. This MESFET has good electron transportation properties to achieve higher frequency operation, featuring high reproducibility and uniformity by using the most matured fabrication process technology equal to conventional MESFET's. Recently, the AlGaAs cap layer was introduced to achieve higher breakdown voltage, and an ion-implantation condition and LDD structure have been optimized for better linearity.
  
  Structure of an Advanced Pulse-doped MESFET

Optimum Solution for Power Applications

• While the drain current of conventional MESFET's shows square law characteristics to the gate voltage, that of the pulse-doped MESFET is very linear with extremely low distortion performance. Furthermore, the device maintains a high transconductance (gm) even at a higher drain current region, exhibiting very flat gm characteristics. Such remarkable features are quite suitable for power applications and SEI applies the pulse-doped technology for all microwave products devices.
  
  Ids and gm vs Vg

Power Amplifier Module for Mobile/WLL Base Station

• SEI provides a rich lineup of power amplifier modules for use in the base stations of mobile and wireless local loop (WLL) systems. The lineup includes the products for the 800MHz/1.5GHz-band PDC/GSM/AMPS cellular phone, the 1.9GHz personal handy phone (PHS), and the wide-band CDMA. SEIﾕs PA module mainly covers the applications as driver-stage amplifiers, responding to various specifications of the output power, the P1dB, the IM3, and the power supply voltages. The main feature of SEIﾕs PA modules is to achieve the specified distortion performances with lower power consumption.
  
  Standard Power Amplifier Lineup

"Trimmable" is better for driver stage

• In W-CDMA systems, the gain versus frequency characteristics of a circuit is quite important. The characteristics depend upon the layout design of the PC board. The specified performance must be achieved for the total circuits. The new product, "Gain Trimmable Power Amplifier Module" is a strategic key device for many designers of the W-CDMA base station.
  
  Example of Tuning Result in P0622101H

Product Lineup

Power GaAs MESFET       [Download Data Sheets]

Power Amplifer Modules for W-CDMA        [Download Data Sheets]

Power Amplifier Modules for PHS Base Station       [Download Data Sheets]

800MHz-band/1.5GHz-band Power Amplifier Modules       [Download Data Sheets]