A Low Voltage Inverter Based Differential Amplifier for Low Power Switched Capacitor Applications

A low voltage and low power inverter based differential amplifier is presented. The input stage is fully differential in operation and the output stage employ class C inverter to enhance the gain. An on-chip body bias improves the slew rate performance. The amplifier is implemented in UMC 90 nm technology. With load capacitance of 100fF, the amplifier delivers DC gain of 81dB and unity gain bandwidth of 33.88MHz at 41° phase margin. For a dual power supply voltage of ±350mV, the quiescent current and power consumption are 2.37μA and 1.66μW respectively. The amplifier achieves a figure of merit of 2117. With the bulk of all the transistors slightly forward biased by a fixed bias potential, the power dissipation of 672nW and figure of merit of 5431 are achieved.