Power-on reset (POR), power supply monitor (PSM) and control of DC-DC converters are required circuits in embedded systems. Mobile systems often need special power down modes where these three functions POR, PSM and DC-DC control must be executed taking less than 1 mu A of current in total. Traditional design techniques meet a fatal area problem as they try to reduce current by increasing the area of the design. This paper presents a power management (PMG) system designed in a 1.2V/90nm CMOS process. The system is part of a Cortex m3-based microcontroller. The PMG offers the POR, PSM and DCDC converter control functions for a 1.2V regulated supply and POR, PSM for the battery. This paper presents the best published combination of high precision (< 1.2% variation of trip voltages), power consumption (250nW), area (0.044mm(2)), and number of trip points observed (18).