An Ultra Low Transient GaAs FET VHF Switch

A simple unbalanced GaAs FET switch is described which has 20 dB lower peak transients than commercial balanced diode designs. An auto-transformer neutralization circuit provides more than 55 dB off-isolation over a three octave bandwidth. A novel scheme which derives both drive and bias from Schottky TTL gates eliminates the bipolar supplies and discrete drive circuitry usually found in high speed switches. A low level transient caused by carrier trapping in the GaAs material is described.