A GaAs Heterojunction Bipolar Transistor ECL Divide by 4 Circuit Operating at Greater than 5.6 GHz

GaAs/GaAlAs HJBT divide by four circuits have been fabricated with 1.5μm and 2μm feature sizes (2.5μm and 4μm equivalent emitters). The maximum divide by four frequency was determined as a function of DC bias for both geometries. On-wafer measurements were compared with those obtained from ICs assembled into conventional, and microwave packages. The highest divide by four frequency of 5.6GHz was attained by a 2.5μm emitter transistor IC.