Single Miller capacitor compensated multistage amplifiers for large capacitive load applications

This work presents two compensation techniques for low-voltage three-stage amplifiers driving large capacitive loads: single Miller capacitor compensation (SMC) and single Miller capacitor feedforward compensation (SMFFC). They are implemented in amplifiers fabricated in standard 0.5 μm CMOS technology. The use of a single Miller compensation capacitor in three stage amplifiers is explored. The small compensation capacitors used in the proposed topologies enhance the bandwidth and significantly reduce the silicon area. Feedforward paths are properly used to improve the stability of the amplifiers. Experimental results show that the SMC and SMFFC amplifiers achieve gain-bandwidth products of 4.6 MHz and 9 MHz, respectively, when driving a load of 250 Ω/120 pF. Each amplifier operates from a ±1 V supply, dissipates less than 0.42mW of power and occupies less than 0.02 mm² of silicon area.