VCCS controlled LDO with small on-chip capacitor

Abstract

A stable LDO (Low Drop-Out linear regulator) using VCCS (Voltage Control Current Source) is presented. The LDO is designed and implemented on GF 2P4M 0.35μm CMOS technology. Compared with previous compensation scheme, VCCS can implement a real stable LDO with a small on-chip capacitor of 1pF, whose stability is not affected by the variable ESR (Equivalent Series Resistor). The united gain frequency can achieve 1.5MHz, improving the transient response. Test result shows that the LDO is stable over the full load current, with a maximum output current of 100mA.