MAX797H

96% Efficiency
Up to 40V Power Input
2.5V to 6V Adjustable Output
Preset 3.3V and 5V Outputs (at up to 10A)
5V Linear-Regulator Output
Precision 2.505V Reference Output
Automatic Bootstrap Circuit
150kHz/300kHz Fixed-Frequency PWM Operation
Programmable Soft-Start
375A Quiescent Current (VIN = 12V, VOUT = 5V)
1A Shutdown Current

Notebook and Subnotebook Computers Industrial Controls

V+ to GND ...................................................................................-0.3V to 36V
GND to PGND............................................................................................±2V
VL to GND......................................................................................-0.3V to 7V
BST to GND .................................................................................-0.3V to 46V
DH to LX ........................................................................-0.3V to (BST + 0.3V)
LX to BST ......................................................................................-7V to 0.3V
SHDN to GND...............................................................................-0.3V to 36V
SYNC, SS, REF, FB, SKIP, DL to GND.................................-0.3V to (VL + 0.3V)
CSH, CSL to GND...........................................................................-0.3V to 7V
VL Short Circuit to GND..................................................................Momentary
REF Short Circuit to GND ..............................................................Continuous
VL Output Current .................................................................................50mA
Continuous Power Dissipation (TA = +70°C)
SO (derate 8.70mW/°C above +70°C).............................................696mW
Operating Temperature Range
MAX797HESE .......................................................................-40°C to +85°C
Storage Temperature Range .............................................-65°C to +160°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.

The MAX797H high-performance, step-down DC-DC converter provides main CPU power in battery-powered systems. A 40V rating on the power stage's input allows operation with high-cell-count batteries and a wide range of AC adaptors. This buck controller achieves 96% efficiency by using synchronous rectification and Maxim's proprietary Idle Mode™ control scheme to
extend battery life at full-load (up to 10A) and no-load outputs. Excellent dynamic response of MAX797H corrects output transients caused by the latest dynamic-clock CPUs within five 300kHz clock cycles. Unique bootstrap circuitry drives inexpensive N-channel MOSFETs, reducing system cost and eliminating the crowbar switching currents found in some PMOS/NMOS switch designs.

The MAX797H has a logic-controlled and synchronizable fixed-frequency, pulse-width-modulating (PWM) operating mode, which reduces noise and RF interference in sensitive mobile-communications and pen-entry applications. The SKIP override input allows automatic switchover to idle-mode operation (for high-efficiency pulse skipping) at light loads, or forces fixed-frequency mode for lowest noise at all loads. The MAX797H is pin compatible with the popular MAX797, but has a higher input voltage range.

The MAX797H comes in a 16-pin narrow SO package.