A Low-Voltage Silicon Bipolar Rf Front-End For Pcn Receiver Applications

Monolithic microstrip transformers are used to perform the coupling and phase-splitting functions in a bipolar low-noise amplifier and mixer designed for 1.9GHz wireless receiver applications. These circuits are fabricated in a production 0.8/spl mu/m BiCMOS process with a transistor transit frequency of 11GHz. Using reactive feedback and coupling elements in place of resistors significantly improves the noise figure through the reduction of resistor thermal noise, and also allows both the low-noise amplifier and the mixer to operate at supply voltages below 2V.