Patent ID: 8305148

Claim:
A Class A amplifier circuit comprising: a bipolar, common emitter-connected (CE) transistor having a base that receives a DC bias voltage and an AC signal to be amplified, wherein the CE transistor has a transconductance vs. base-emitter voltage (V BE ) characteristic which, when plotted, shows a transconductance that increases with an increasing V BE to a maximum, then drops, then tapers off, wherein there is an inflection point between the maximum transconductance and where the transconductance tapers off; a bipolar cascode transistor having an emitter coupled to a collector of the CE transistor, a collector of the cascode transistor providing an amplified AC signal; and a DC bias circuit coupled to provide a DC bias voltage to the base of the CE transistor, wherein the DC bias voltage is set to cause the CE transistor to substantially operate around the inflection point within a range of temperatures.