Patent ID: 6552614
Filing Date: 2003-04-22
Classification: H03F,H03G

Abstract:
A programmable gain amplifier (PGA), comprising:a power amplifier stage having an input, an output and a bias input; and a bias current-setting circuit having an output coupled to the power amplifier stage bias input, wherein the bias current-setting circuit is adapted to program a bias current of the power amplifier stage; the bias current-setting circuit comprising: a bandgap generator having an input and an output, the bandgap generator output coupled to the power amplifier stage bias input; an external bias resistor coupled to the input of the bandgap generator; a variable gain amplifier (VGA) having an input and an output, the VGA output coupled to the power amplifier stage bias input, the VGA input coupled to the bandgap generator output, the VGA adapted to provide bias current for the power amplifier stage, the bandgap generator producing a nominal bias current at the output; a digital-to-analog converter (DAC) having an input and an output adapted to receive a digital signal at the input and produce an analog signal at the output, the DAC output coupled to a bias input of the VGA; and a bias code generator coupled to the DAC input adapted to program the bias current of the power amplifier stage.