Rainbow Electronics MAX1715 - Manual

For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
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
Features
♦ Ultra-High Efficiency
♦ No Current-Sense Resistor (lossless I
LIMIT )
♦ Quick-PWM with 100ns Load-Step Response
♦ 1% V
OUT 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
♦ Over/Undervoltage Protection
♦ 1.7ms Digital Soft-Start
♦ Drives Large Synchronous-Rectifier FETs
♦ Power-Good Indicator
MAX1715
Ultra-High Efficiency, Dual Step-Down
Controller for Notebook Computers
________________________________________________________________ Maxim Integrated Products 1
19-1541; Rev 1; 5/00
Pin Configuration appears at end of data sheet.
Quick-PWM is a trademark of Maxim Integrated Products.
-40°C to +85°C
PART
MAX1715EEI
TEMP. RANGE PIN-PACKAGE
28 QSOP
Ordering Information
EVALUATION KIT
AVAILABLE
V CC
OUTPUT1
1.8V
BATTERY
4.5V TO 28V
ILIM1
ON2
DL1
TON
OUT1
LX1
DH1
FB1 AGND
V DD
BST1
ILIM2
ON1
REF
DL2
PGND
OUT2
LX2
DH2
FB2
V+
BST2
SKIP
5V INPUT
PGOOD
OUTPUT2
2.5V
MAX1715
Minimal Operating Circuit