MAX1715 Datasheet, PDF (1/28 Pages) Maxim Integrated Products – Ultra-High Efficiency, Dual Step-Down Controller for Notebook Computers

19-1541; Rev 0; 1/00
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Ultra-High Efficiency, Dual Step-Down
Controller for Notebook Computers
General Description
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-
rectifier MOSFETs.
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
data sheet.
Applications
Notebook Computers
CPU Core Supply
Chipset/RAM Supply as Low as 1V
1.8V and 2.5V I/O Supply
Pin Configuration appears at end of data sheet.
Features
o Ultra-High Efficiency
o No Current-Sense Resistor (lossless I_LIMIT)
o Quick-PWM with 100ns Load-Step Response
o 1% V_OUT Accuracy over Line and Load
o Dual-Mode Fixed 1.8V/3.3V/Adj or 2.5V/Adj Outputs
o Adjustable 1V to 5.5V Output Range
o 2V to 28V Battery Input Range
o 200/300/420/540kHz Nominal Switching Frequency
o Over/Undervoltage Protection
o 1.7ms Digital Soft-Start
o Drives Large Synchronous-Rectifier FETs
o Power-Good Indicator
PART
MAX1715EEI
Ordering Information
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
28 QSOP
5V INPUT
OUTPUT1
1.8V
Minimal Operating Circuit
VDD
V+
VCC
ILIM1
ILIM2
ON1
ON2
BST1 BST2
DH1 DH2
LX1
LX2
DL1
DL2
TON PGND
OUT1 OUT2
PGOOD
REF
SKIP
FB1 AGND FB2
BATTERY
4.5V TO 28V
MAX1715
OUTPUT2
2.5V
Quick-PWM is a trademark of Maxim Integrated Products.
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