Design of 1 V bulk-driven programmable gain instrumentation amplifier

Han, Tao
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This thesis describes the different aspects of the design and implementation of a programmable instrumentation amplifier with standard CMOS technology. The instrumentation amplifier is made up of 3 Op Amps with the gain stages of 1, 5, 10, 20, and 30 digitally selectable. Two identical Op Amps using bulk-driven technique (also called "substrate input") as the input stage of the instrumentation amplifier is presented and discussed. This new structure effectively overcomes the threshold voltage barrier, improves signal swing and dynamic range and allows the amplifier operating at power supply as low as 1 volt. The third Op Amp with transimpedance input structure and modified output stage enables the amplifier to drive a load of 1 K[Omega] resistor in parallel with 20 pF capacitor. As a result, the instrumentation amplifier achieves rail-to-rail input common-mode range of -481 mV [Difference] 441 mV and rail-to-rail output swing of -483 mV [Difference] 476.6 mV. The Op Amp achieves DC gain of 71.4dB, unity-gain frequency of 2.75 MHz, and phase margin of 810. The entire design has implemented in a digital 1.2 [Mu]m CMOS process with power consumption of 605.5 [Mu]W.

Electrical and computer engineering, Electrical engineering