Features: ` Dual PWM Buck Controllers (+3.3V and +5V)
` Two Precision Comparators or Level Translators
` 95% Efficiency
` 420A Quiescent Current, 70A in Standby (linear regulators alive)
` 25A 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™)Application · Notebook Computers
· Portable Data Terminals
· Communicating Computers
· Pen-Entry SystemsPinout
SpecificationsV+ to GND................................................................-0.3V to 36V
PGND to GND ........................................................................±2V
VL to GND ..................................................................-0.3V to 7V
BST3, BST5 to GND ..................................................-0.3V to 36V
LX3 to BST3 ...............................................................-7V to 0.3V
LX5 to BST5 ...............................................................-7V to 0.3V
Inputs/Outputs to GND
(D1, D2, SHDN, ON5, REF, SS5, CS5,
FB5, SYNC, CS3,FB3, SS3, ON3) ...................-0.3V to (VL + 0.3V)
VH to GND ...............................................................-0.3V to 20V
Q1, Q2 to GND .............................................-0.3V to (VH + 0.3V)
DL3, DL5 to PGND.........................................-0.3V to (VL + 0.3V)
DH3 to LX3 ...............................................-0.3V to (BST3 + 0.3V)
DH5 to LX5 ...............................................-0.3V to (BST5 + 0.3V)
REF, VL Short to GND..................................................Momentary
REF Current.........................................................................20mA
VL Current ..........................................................................50mA
Continuous Power Dissipation (TA = +70°C)
SSOP (derate 9.52mW/°C above +70°C)........................762mW
Operating Temperature Ranges
MAX786CAI/MAX786_CAI ......................................0°C to +70°C
MAX786EAI/MAX786_EAI....................................-40°C to +85°C
Lead Temperature (soldering, 10sec) ............................+300°C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DescriptionThe MAX786 is a system-engineered power-supply controller for notebook computers or similar batterypowered equipment. MAX786 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-batterydetection comparators.
High efficiency of MAX786(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 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 30F per ampere of load. Line- and loadtransient responses are terrific, with a high 60kHz unitygain crossover frequency allowing output transients to be corrected within four or five clock cycles. Low system cost of MAX786 is achieved through a high level of integration and the use of low-cost, external N-channel MOSFETs.
Other features of MAX786 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 MAX786 is a monolithic, BiCMOS IC available in fine-pitch, surface-mount SSOP packages.
MAX786 Data Sheet
