Novel tunable GaAs MESFET OTA-C integrators suitable for high precision filtering applications

The design of novel, differential input operational-transconductance-amplifier (OTA-C) integrators for realization in 0.5- mu m, 20-GHz GaAs MESFET technology is described. It is shown that due to certain unique features of the single-ended OTA, extension to a fully balanced differential form requires considerably less than doubling of the number of components. The circuits, which feature separate control of gain and cutoff frequency, are particularly suited to high-precision, very-high-Q filtering applications. The fully balanced integrator is very linear, and searching tests conducted over a wide range of transconductance and operating conditions reveal that the total harmonic distortion levels are low.<
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