An Operational Amplifier with Multipath Miller Zero Cancellation for RHP Zero Removal

The paper presents a Multipath Miller Zero Cancellation (MMZC) technique to remove the Right Half Plane Zero (RHPZ) in Miller compensated operational amplifiers. For comparison four different CMOS amplifiers have been integrated: a reference circuit without RHPZ removal, two circuits with traditional resistor and cascode removal techniques and finally the circuit with Multipath Miller Zero Cancellation Measurements confirm that MMZC increases the bandwidth of a microamp Miller compensated output stage from 3MHz to 3MHz, while maintaining the robustness necessary for class-AB operation. The traditional methods for RHPZ removal fail under the same conditions and give rise to peaking (´the output bump´)