MAX1711

Ultra-High Efficiency
 No Current-Sense Resistor (Lossless ILIMIT)
Quick-PWM with 100ns Load-Step Response
±1% VOUT Accuracy over Line and Load
4-Bit On-Board DAC (MAX1710)
5-Bit On-Board DAC (MAX1711/MAX1712)
0.925V to 2V Output Adjust Range(MAX1711/MAX1712)
 2V to 28V Battery Input Range
 200/300/400/550kHz Switching Frequency
 Remote GND and VOUT Sensing
 Over/Undervoltage Protection
 1.7ms Digital Soft-Start
 Drive Large Synchronous-Rectifier FETs
 2V ±1% Reference Output
 Power-Good Indicator
Small 24-Pin QSOP Package

Notebook Computers
Docking Stations
CPU Core DC-DC Converters
Single-Stage (BATT to VCORE) Converters
Two-Stage (+5V to VCORE) Converters

V+ to GND ..............................................................-0.3V to +30V
V_CC, V_DD to GND .................................................... -0.3V to +6V
PGND to GND..................................................................... ±0.3V
SHDN, PGOOD to GND ............................................ -0.3V to +6V
OVP, ILIM, FB, FBS, CC, REF, D0D4,
GNDS, TON to GND.....................................-0.3V to (VCC + 0.3V)
SKIP to GND (Note 1).................................-0.3V to (VCC + 0.3V)
DL to PGND................................................-0.3V to (VDD + 0.3V)
BST to GND............................................................-0.3V to +36V
DH to LX ....................................................-0.3V to (BST + 0.3V)
LX to BST.................................................................-6V to +0.3V
REF Short Circuit to GND ..........................................Continuous
Continuous Power Dissipation (T_A = +70°C)
24-Pin QSOP (derate 9.5mW/°C above +70°C)..............762mW
Operating Temperature Range .........................-40°C to +85°C
Junction Temperature.....................................................+150°C
Storage Temperature Range ...........................-65°C to +165°C
Lead Temperature (soldering, 10s) ...............................+300°C

Note 1: SKIP may be forced below -0.3V, temporarily exceeding the absolute maximum rating, for the purpose of debugging prototype breadboards using the no-fault test mode. Limit the current drawn to -5mA maximum.

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 MAX1710/MAX1711 step-down controllers are intended for core CPU DC-DC converters in notebook computers. They feature a triple-threat combination of ultra-fast transient response, high DC accuracy, and high efficiency needed for leading-edge CPU core power supplies. Maxim's proprietary Quick-PWM™ quick-response, constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns "instant-on" response to load transients while maintaining a relatively constant switching frequency.

High DC precision is ensured by a 2-wire remote-sensing scheme that compensates for voltage drops in both the ground bus and supply rail. An on-board, digital-toanalog converter (DAC) sets the output voltage in compliance with Mobile Pentium II^® CPU specifications.

The MAX1710 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by an ability to drive very large synchronousrectifier MOSFETs.Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, 2-stage conversion(stepping down the +5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size.

The MAX1710/MAX1711 are identical except that the MAX1711 have 5-bit DACs and the MAX1710 has a 4-bit DAC. Also, the MAX1711 has a fixed overvoltage protection threshold at VOUT = 2.25V and undervoltage protection at VOUT = 0.8V whereas the MAX1710 has variable thresholds that track VOUT. The MAX1711 is intended for applications where the DAC code may change dynamically.