Characterization and improvement of GaAs HEMT analog switches for sampled-data applications

This paper presents design consideration and experimental comparison of GaAs HEMT analog switches for high-speed and high-precision sampled-data applications. At first, basic pass-transistor switches fabricated in a 0.5-/spl mu/m GaAs HEMT technology are measured for characterization of transient errors induced due to clock-feedthrough and charge transfer. In order to improve the switch dynamic performances, a dual dummy transistor compensation technique is used and related driver circuitry is developed. On-wafer measurements demonstrate that the improved switch provides a significant reduction of the transient errors, a reasonable dynamic range, and a high isolation. The switch with a 0.53 pF load capacitor achieves a total harmonic distortion below -55 dB and -38 dB at 10 MHz and 1.0 GHz clock frequency, respectively.<
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