19-1541; Rev 0; 1/00
Ultra-High Efficiency, Dual Step-Down
Controller for Notebook Computers
No Current-Sense Resistor (lossless I
Quick-PWM with 100ns Load-Step Response
Accuracy over Line and Load
Dual-Mode Fixed 1.8V/3.3V/Adj or 2.5V/Adj Outputs
Adjustable 1V to 5.5V Output Range
2V to 28V Battery Input Range
200/300/420/540kHz Nominal Switching Frequency
1.7ms Digital Soft-Start
Drives Large Synchronous-Rectifier FETs
The MAX1715 PWM controller provides the high effi-
ciency, excellent transient response, and high DC out-
put accuracy needed for stepping down high-voltage
batteries to generate low-voltage CPU core, I/O, and
chipset RAM supplies in notebook computers.
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.
The MAX1715 achieves high efficiency at a reduced
cost by eliminating the current-sense resistor found in
traditional current-mode PWMs. Efficiency is further
enhanced by its ability to drive very large synchronous-
Single-stage buck conversion allows this device 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 mini-
mum possible physical size.
The MAX1715 is intended for CPU core, chipset,
DRAM, or other low-voltage supplies as low as 1V. The
MAX1715 is available in a 28-pin QSOP package. For
applications requiring VID compliance or DAC control
of output voltage, refer to the MAX1710/MAX1711 data
sheet. For a single-output version, refer to the MAX1714
-40°C to +85°C
CPU Core Supply
Chipset/RAM Supply as Low as 1V
1.8V and 2.5V I/O Supply
Minimal Operating Circuit
4.5V TO 28V
Pin Configuration appears at end of data sheet.
FB1 AGND FB2
Quick-PWM is a trademark of Maxim Integrated Products.
Maxim Integrated Products
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.