A programmable gain amplifier for multi-mode multi-standard wireless receivers

A programmable-gain-amplifier (PGA) based on open-loop structure is presented in this paper for multi-mode multi-standard receivers. The variable gain is obtained by cascading one 0-15dB variable gain stage with three 15-dB fixed gain stages. Variation of gain is achieved by switch-controlled output resistor network. Measurement results indicate that the PGA has 0-62 dB variable gain range, 1 dB gain resolution, and less than 0.27 dB gain error. And the -3 dB bandwidth at the maximum gain configuration is 12 MHz. The entire circuit consumes 1.9 mA current from a 1.8 V supply voltage.