19-1960; Rev 3; 8/02
Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP -II)
General Description
The MAX1718 step-down controller is intended for core
CPU DC-DC converters in notebook computers. It fea-
tures a dynamically adjustable output, ultra-fast transient
response, high DC accuracy, and high efficiency need-
ed 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.
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 MAX1718 has an internal multiplexer
that accepts three unique 5-bit VID DAC codes corre-
sponding 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.
The internal DAC of the MAX1718B is synchronized to
the slew-rate clock for improved operation under
aggressive power management of newer chipsets and
operating systems that can make incomplete mode tran-
sitions.
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 bat-
tery) at a higher switching frequency allows the mini-
mum possible physical size.
The MAX1718 is available in a 28-pin QSOP package.
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
Features
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
200/300/550/1000kHz Switching Frequency
Over/Undervoltage Protection
Drives Large Synchronous-Rectifier FETs
700µA (typ) I
CC
Supply Current
2µA (typ) Shutdown Supply Current
2V ±1% Reference Output
VGATE Blanking During Transition
Small 28-Pin QSOP Package
MAX1718
Ordering Information
PART
MAX1718EEI
MAX1718BEEI
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 QSOP
28 QSOP
Minimal Operating Circuit
5V INPUT
BATT 2V TO 28V
V
CC
SKP/SDN
SHUTDOWN
ILIM
V
DD
V+
BST
MAX1718
DH
D0
D1
DUAL MODE VID
MUX INPUTS
D2
D3
D4
ZMODE
SUS
S0
S1
TIME
FB
NEG
POS
LX
DL
GND
OUTPUT
0.6V TO 1.75V
Applications
IMVP-II™ Notebook Computers
2-Cell to 4-Cell Li+ Battery to CPU Core Supply
Converters
5V to CPU Core Supply Converters
Pin Configuration appears at end of data sheet.
MUX CONTROL
SUSPEND
INPUT
DECODER
CC
REF
VCC
†
Patent pending.
Quick-PWM is a trademark of Maxim Integrated Products.
IMVP-II is a trademark of Intel Corp.
TON
VGATE
OVP
POWER-GOOD
OUTPUT
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
