The MAX786CAI 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 rectification and PWM operation at heavy loads, and Idle Mode operation at light loads. The MAX786CAI 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 system 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 synchronizable oscillator for noise-sensitive applications such as electromagnetic pen-based systems and communicating computers. The MAX786CAI is a monolithic, BiCMOS IC available in fine-pitch, surface-mount SSOP packages.
Feature
- Dual PWM Buck Controllers (+3.3V and +5V)
- Two Precision Comparators or Level Translators
- 95% Efficiency
- 420μA Quiescent Current, 70μA in Standby (linear regulators alive)
- 25μA Shutdown Current (+5V linear alive)
- 5.5V to 30V Input Range
- Small SSOP Package
- Fixed Output Voltages:
- 3.3V (standard)
- 3.45V (High-Speed Pentium?)
- 3.6V (PowerPC?)
Applications
- Communication Systems
- Notebook Computers
- Pen-Entry Systems
- Portable Data Terminals