Maxim MAX786 Dual-Output Power-Supply Controller Datasheet

MAX786 is a system-engineered power-supply controller for notebook computers or similar battery-powered equipment. It provides two high-performance step-down (buck) pulse-width modulators (PWMs) for +3.3V and +5V. Other features include dual, low-dropout, micropower linear regulators for CMOS/RTC back-up, and two precision low-battery-detection comparators. High efficiency (95% at 2A; greater than 80% at loads from 5mA to 3A) is achieved through synchronous recti- fication and PWM operation at heavy loads, and Idle ModeTM operation at light loads. The MAX786 uses physically small components, thanks to high operating frequencies (300kHz/200kHz) and a new current-mode PWM architecture that allows for output filter capacitors as small as 30µF per ampere of load. Line- and load-transient responses are terrific, with a high 60kHz unity-gain crossover frequency allowing output transients to be corrected within four or five clock cycles. Low sys- tem cost is achieved through a high level of integration and the use of low-cost, external N-channel MOSFETs. Other features include low-noise, fixed-frequency PWM operation at moderate to heavy loads, and a synchro- nizable oscillator for noise-sensitive applications such as electromagnetic pen-based systems and communi- cating computers. The MAX786 is a monolithic, BiCMOS IC available in fine-pitch, surface-mount SSOP packages.

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