A programmable multi-output technique in LDO regulator for multi-reference SAR ADC application

A multi-output and high-precision output-tuning technique in a low-dropout regulator (LDO) for multi-reference low-power SAR ADC is proposed in this article. A programmable resistor string is utilised for multi-output, and a tuneable resistor ladder is introduced in the feedback network for high-precision LDO output control. The applicability and superiority of this proposed approach are verified by the design of a 65nm CMOS LDO with programmable output. The design results show that the LDO output ranges from 0.4 to 1.2V with 0.2V/step, and the output voltage can be precisely tuned by 0.05V/step within a range of 0.8-1.15V. The line regulation of this LDO is about 0.27mV/V. The multi-output ability enables the LDO to drive five light loads simultaneously, and the high-precision tuning ability can effectively overcome the output errors caused by power supply variation, temperature drift and other non-ideal factors.