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A multifunctional programmable gain amplifier(PGA) that provides gain and offset adjusting abilities for high-definition video analog front-ends(AFE) is presented. With a switched-capacitor structure, the PGA also acts as a sample and holder of the analog-to-digital converter(ADC) in the AFE to reduce the power consumption and chip area of the whole AFE. Furthermore, the PGA converts the single-ended video signal into differential signal for the following ADC to reject common-mode noise and interferences. The 9-bit digital-to-analog converter(DAC) for gain and offset adjusting is embedded into the switched capacitor networks of the PGA. A video AFE integrated circuit based on the proposed PGA is fabricated in a 0.18- m process. Simulation and measurement results show that the PGA achieves a gain control range of 0.90 to 2.34 and an offset control range of –220 to220 mV while consuming 10.1 mA from a 1.8 V power supply.
With a switched-capacitor structure, the PGA also acts as a sample and holder of the analog- to-digital converter (ADC) in the AFE to reduce the power consumption and chip area of the whole AFE. The PGA converts the single-ended video signal into differential signal for the following ADC to reject common-mode noise and interferences. The 9-bit digital-to-analog converter (DAC) for gain and offset adjustment is embedded into the switched capacitor networks of the PGA. A video AFE integrated circuit based on the proposed PGA is fabricated in a 0.18-m process. Simulation and measurement results show that the PGA achieves a gain control range of 0.90 to 2.34 and an offset control range of -220 to 220 mV while consuming 10.1 mA from a 1.8 V power supply.