Gallium Nitride High Electron Mobility Transistors, GaN HEMTs, are fast becoming the ampli-fier  designer’s  device  of  choice  for  applications  ranging  from  pulsed  radar  to  communication systems.  This  is  primarily  due  to  the  high  power  density  as  compared  to  Gallium  Arsenide, GaAs and high  frequency capability as compared  to LDMOS devices. For an equivalent semi-conductor  die  physical  size  a  GaN  device  can  produce  two  to  three  times  more  RF  output  power.  Along  with  the  higher  power  density  comes  increased  robust  operation  and  reliability. The voltage breakdown of GaN devices  is in excess of 100 volts compared to 7 to 20 volts for equivalent power GaAs devices. The key characteristics of GaN are:  High Output Power - High Breakdown Voltage,   High Peak Current Capability;  Good Efficiency -   Low knee Voltage-High Breakdown Voltage combination,   Low Semiconductor Losses,   Ability to cutoff current at high voltage; High Reliability  -   High Temperature Operation,   High Reliability,   Low Thermal Resistance.