A dual-path bandwidth extension amplifier topology with dual-loop parallel compensation

A dual-path amplifier topology with dual-loop parallel compensation technique is proposed for low-power three-stage amplifiers. By using two parallel high-speed paths for high-frequency signal propagation, there is no passive capacitive feedback network loaded at the amplifier output. Both the bandwidth and slew rate are thus significantly improved. Implemented in a 0.6-μm CMOS process, the proposed three-stage amplifier has over 100-dB gain, 7-MHz gain-bandwidth product, and 3.3-V/μs average slew rate while only dissipating 330 μW at 1.5 V, when driving a 25-kΩ//120-pF load. The proposed amplifier achieves at least two times improvement in bandwidth-to-power and slew-rate-to-power efficiencies than all other reported multistage amplifiers using different compensation topologies.