19-4781; Rev 0; 11/98
NUAL
KIT MA
ATION
ET
EVALU
TA SHE
WS DA
FOLLO
High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
General Description
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
4-Bit On-Board DAC (MAX1710)
o
5-Bit On-Board DAC (MAX1711)
o
0.925V to 2V Output Adjust Range (MAX1711)
o
2V to 28V Battery Input Range
o
200/300/400/550kHz Switching Frequency
o
Remote GND and V
OUT
Sensing
o
Over/Undervoltage Protection
o
1.7ms Digital Soft-Start
o
Drives Large Synchronous-Rectifier FETs
o
2V ±1% Reference Output
o
Power-Good Indicator
o
Small 24-Pin QSOP Package
MAX1710/MAX1711
The MAX1710/MAX1711 step-down controllers are
intended for core CPU DC-DC converters in notebook
computers. They feature a triple-threat combination of
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-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 fre-
quency.
High DC precision is ensured by a 2-wire remote-sens-
ing scheme that compensates for voltage drops in both
ground bus and the supply rail. An on-board, digital-to-
analog converter (DAC) sets the output voltage in com-
pliance with Mobile Pentium II
®
CPU specifications.
The MAX1710 achieves high efficiency at a reduced
cost by eliminating the current-sense resistor found in
traditional current-mode PWMs. Efficiency is further
enhanced by an ability to drive very large synchronous-
rectifier MOSFETs.
Single-stage buck conversion allows these devices to
directly step down high-voltage batteries for the highest
possible efficiency. Alternatively, 2-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 MAX1710 and MAX1711 are identical except that
the MAX1711 has a 5-bit DAC rather than a 4-bit DAC.
Also, the MAX1711 has a fixed overvoltage protection
threshold at V
OUT
= 2.25V and undervoltage protection
at V
OUT
= 0.8V, whereas the MAX1710 has variable
thresholds that track V
OUT
. The MAX1711 is intended
for applications where the DAC code may change
dynamically.
Ordering Information
PART
MAX1710EEG
MAX1711EEG
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
24 QSOP
24 QSOP
Minimal Operating Circuit
+5V INPUT
V
CC
SHDN
FBS
ILIM
GNDS
OVP*
V
DD
V+
BST
DH
OUTPUT
0.925V TO 2V
(MAX1711)
LX
DL
PGND
FB
SKIP
BATTERY
4.5V TO 28V
Applications
Notebook Computers
Docking Stations
CPU Core DC-DC Converters
Single-Stage (BATT to V
CORE)
Converters
Two-Stage (+5V to V
CORE
) Converters
QUICK-PWM is a trademark of Maxim Integrated Products.
Mobile Pentium II is a registered trademark of Intel Corp.
Pin Configuration appears at end of data sheet.
D/A
INPUTS
*MAX1710 ONLY
**MAX1711 ONLY
MAX1710
MAX1711
REF
CC
D0
D1
D2
D3
D4** GND
________________________________________________________________
Maxim Integrated Products
1
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.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
