A 75dB Programmable Gain Amplifier for Dual Mode Wireless Receivers
In this paper, a programmable gain amplifier (PGA) is designed and implemented for GPS/Galileo and WCDMA dual mode receiver using TSMC 0.18μm CMOS technology. The 0-75dB variable gain range is obtained by cascading a 0-15dB variable gain stage and four 15dB fixed gain stages. An open-loop structured fully-differential amplifier with source feedback resistor is adopted in basic gain stage. Variation of gain is achieved by switch-controlled output resistor network. Gm-boost structure is used in main amplifier. A DC-offset canceller circuit using DC negative feedback technique is proposed to eliminate the DC-offset of the PGA. Post-simulation shows that the PGA has 0-75dB variable gain range, 1dB gain resolution and less than 0.3dB gain error; the minimum DC attenuation is about 15dB over the whole gain range; -3dB bandwidth at the maximum gain configuration is about 15MHz; differential output peak to peak voltage is greater than 1V; and the entire circuit consumes about 3.6mA current under 1.8V supply voltage.
X. N. Fan et al., "A 75dB Programmable Gain Amplifier for Dual Mode Wireless Receivers", Applied Mechanics and Materials, Vols. 229-231, pp. 1609-1613, 2012