The MC33128 is a power management controller specifically designed for use in battery powered cellular telephone and pager applications. This device contains all of the active functions required to interface the user to the system electronics via a microprocessor. This integrated circuit consists of a low dropout voltage regulator with powerup reset for MPU power, two low dropout voltage regulators for independant powering of analog and digital circuitry, and a negative charge pump voltage regulator for full depletion of gallium arsenide MESFETs.