Design and analysis of high-gain amplifiers in flexible self-aligned a-IGZO thin-film transistor technology

This paper presents two high-gain amplifiers fabricated in a flexible self-aligned amorphous indium gallium zinc oxide thin-film transistor (TFT) technology. One common-source amplifier relies on positive feedback to provide a voltage gain of 17 dB, and a bandwidth of 79 kHz from a dc power of only 0.76 mW. One cascode amplifier provides a voltage gain of 25 dB, and a bandwidth of 220 kHz from a dc power of 2.32 mW. The chip areas of the amplifiers are 7.5 and 10.3 mm2, respectively. By using a gain-enhancement technique in the first amplifier, gain, dc power consumption, and chip area are greatly improved. The presented amplifiers are designed for using as audio pre-amplifiers in a radio receiver. The presented measurements confirm that the amplifiers meet the requirements for this purpose. The circuits are designed using the Verilog-A Rensselaer Polytechnic Institute-amorphous TFT model; circuit simulations are also presented for comparison with the hardware characterization. Additionally, the impact of process variations on the amplifiers is analyzed and discussed in details.