Wide-Band High-Gain Limiting Amplifier with Parallel Resistor-Transistor Source Loads

摘要

An amplifier has a wide bandwidth and a high gain by using parallel loads. Each load has a load resistor and a load p-channel transistor in parallel. The drain voltages of differential n-channel transistors can be set by the load resistors, while switching current is provided by the load p-channel transistors. The parallel load provides a high impedance to the drain nodes yet still provides driving current. A transconductance stage with a pair of differential transistors and two parallel loads drives a shunt-shunt-feedback stage that has another pair of differential transistors and two more parallel loads. Shunt resistors between the gate and drain of the differential transistors in the shunt-shunt-feedback stage provide shunt feedback and low impedance. Several pairs of transconductance and shunt-shunt-feedback stages can be cascaded together. The cascaded amplifier may be used as a signal repeater.