MAX1718T

` Quick-PWM Architecture
` ±1% V_OUT Accuracy Over Line and Load
` 5-Bit On-Board DAC with Input Muxes
` Precision-Adjustable V_OUT Slew Control
` 0.6V to 1.75V Output Adjust Range
` Precision Offset Control
` Supports Voltage-Positioned Applications
` 2V to 28V Battery Input Range
` Requires a Separate 5V Bias Supply
` 200kHz/300kHz/550kHz/1000kHz Switching Frequency
` Overvoltage/Undervoltage Protection
` Drives Large Synchronous-Rectifier FETs
` 700A (typ) I<sub>CC</sub> Supply Current
` 2A (typ) Shutdown Supply Current
` 2V ±1% Reference Output
` VGATE Blanking During Transition
` Small 28-Pin QSOP Package

· 2-Cell to 4-Cell Li+ Battery to CPU Core Supply
· Converters
· 5V to CPU Core Supply Converters

V+ to GND ............................................................-0.3V to +30V
V_CC, V_DD to GND ....................................................-0.3V to +6V
D0D4, ZMODE, VGATE, OVP, SUS to GND .............-0.3V to +6V
SKP/SDN to GND ...................................................-0.3V to +16V
ILIM, CC, REF, POS, NEG, S1, S0,
TON, TIME to GND......................................-0.3V to (V_CC + 0.3V)
DL to GND..................................................-0.3V to (V_DD + 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
28-Pin QSOP (derate 10.8mW/ above +70)..............860mW
Operating Temperature Range ............................-40 to +85
Junction Temperature......................................................+150
Storage Temperature Range .............................-65 to +150
Lead Temperature (soldering, 10s) .................................+300
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 MAX1718T step-down controller is intended for core CPU DC-to-DC converters in notebook computers. It features a dynamically adjustable output, 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-ontime 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.

The output voltage can be dynamically adjusted through the 5-bit digital-to-analog converter (DAC) over a 0.6V to 1.75V range. The MAX1718T has an internal multiplexer that accepts three unique 5-bit VID DAC codes corresponding to performance, battery, and suspend modes. Precision slew-rate control† provides "just-in-time" arrival at the new DAC setting, minimizing surge currents to and from the battery.

A pair of complementary offset control inputs allows easy compensation for IR drops in PC board traces or creation of a voltage-positioned power supply. Voltage positioning modifies the load-transient response to reduce output capacitor requirements and total system power dissipation.

Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the 5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size.

The MAX1718T is available in a 28-pin QSOP package.