This paper describes the design and test of a Power Management Controller (PMC) for microcontroller unit (MCU) automotive applications in 90nm CMOS technology. The requirements for the PMC include a small, robust architecture with low I/O pin count and flexible extended features, no power sequence dependence and real-time monitoring of critical analog signals. The PMC contains circuitry to generate an internal 3.3V regulated supply voltage and to control the regulation of 1.2V supply with external NPN ballast transistor. It also comprises Low Voltage Detector (LVD) and Power-on Reset (POR) circuits for the 1.2V, 3.3V, 3.3V/5V supply of the closest I/O segment, and the unregulated 5V supply. A three way switch circuit is used to bias the N-well of both voltage regulators. This is required to guarantee correct bias and functioning over all start-up conditions and effective power down for both regulators. The circuit has been fabricated in 90nm CMOS technology and silicon results are provided.