A unipolar thin-film transistor-based amplifier with enhanced DC offset suppression

摘要

This letter proposes a unipolar thin-film transistor (TFT)-based amplifier design that can provide enhanced DC offset suppression. The amplifier consists of an input AC coupling network and a capacitor bootstrap amplifier. By making the first pole of the input AC-coupling network coincide with that of the capacitor bootstrap amplifier, a DC offset suppression capability of 40 dB/dec, which is 2x higher than that of the prior arts, can be obtained. An implementation is also proposed and a Rensselaer Polytechnic Institute (RPI) TFT model whose parameters are turned to fit the measured data of our metal-oxide TFT is used to simulate the circuit. Simulation results show that the implementation has 31 dB midband gain, 0.5 Hz-5 kHz bandwidth, 300 mu W power consumptions, and the expected 40 dB/dec DC offset suppression. This design is suitable for applications that need to block large DC interference, such as sensor readout amplifiers.

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