MAX798

96% Efficiency
4.5V to 30V Input Range
1.6V to 6V Adjustable Precision Output
±0.4% Max Total Load-Regulation Error
0.06%/V Max Line-Regulation Error
5V Linear-Regulator Output
Precision 2.505V Reference Output
Automatic Bootstrap Circuit
150kHz/300kHz Fixed-Frequency PWM Operation
Programmable Soft-Start
1.2mA Typical Quiescent Current (VIN = 12V, VOUT = 2.5V)
1A Typical Shutdown Current

Notebook and Subnotebook Computers PDAs and Mobile Communicators

V+ to GND ....................................................................................-0.3V, +36V
GND to PGND............................................................................................±2V
VL to GND .......................................................................................-0.3V, +7V
BST to GND....................................................................................-0.3V, +36V
DH to LX ............................................................................-0.3V, (BST + 0.3V)
LX to BST.........................................................................................-7V, +0.3V
SHDN to GND.................................................................................-0.3V, +36V
SYNC, SS, REF, SKIP, DL to GND ...........................................-0.3V, (VL + 0.3V)
CSH, CSL to GND .............................................................................-0.3V, +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
MAX798ESE............................................................................-40°C to +85°C
Storage Temperature Range ...............................................-65°C to +160°C
Lead Temperature (soldering, 10sec) ..................................................+300°C

The MAX798† high-performance, step-down DC-DC converter provides main CPU power in battery-powered systems. 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. The MAX798's high accuracy meets the demanding requirements of the latest-generation CPUs. Excellent dynamic response 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 of MAX798 found in some PMOS/NMOS switch designs.

The MAX798 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.