Patent ID: 7265632

Claim:
An amplifier circuit, comprising: a current source circuit having a reference resistor, the current source circuit producing first, second and third bias currents that vary with manufacturing variances of the reference resistor; an input amplification stage comprising i) a transconductance stage biased by the first bias current, and ii) a first transimpedance amplifier (TIA) biased by the second bias current, the first TIA having a first feedback resistor coupled between its input and its output, and the input of the first TIA being coupled to an output of the transconductance stage; an output amplification stage biased by the third bias current, the output amplification stage having an input coupled to an output of the first TIA; and a second feedback resistor, coupled between the output of the output amplification stage and the input of the transconductance stage to form a second TIA; wherein the reference resistor, the first feedback resistor and the second feedback resistor are formed using a common manufacturing process.