Patent ID: 7570108

Claim:
A multistage differential amplifier comprising: a first amplifier stage, the first amplifier stage including: a first differential pair of input NPN bipolar transistors with loads coupled to a supply voltage through a first common-mode PMOS transistor; and a first pair of emitter-follower output NPN bipolar transistors coupled to the first differential pair of input transistors; a second amplifier stage, the second amplifier stage including: a second differential pair of input transistors with loads coupled to the supply voltage through a second common-mode transistors; and a second pair of emitter-follower output transistors coupled to the second differential pair of input transistors, wherein the second differential pair of input transistors is coupled to the first pair of emitter-follower output transistors; and a voltage regulator coupled to control the first common-mode transistor, the voltage regulator including: a differential amplifier with a first input from a reference voltage, a second input from a temperature responsive unit, and an output to a third transistor connected between a supply voltage and the temperature responsive unit; and a regulated voltage output node between the third transistor and the temperature responsive unit, wherein the temperature responsive unit includes in series a first resistor, a second resistor, and a diode-connected NPN bipolar transistor.