MAX1712 Datasheet, PDF (1/28 Pages) Maxim Integrated Products – High-Speed, Digitally Adjusted Step-Down Controllers for Notebook CPUs

19-4781; Rev 1; 7/00
EVAALVUAAILTAIOBNLEKIT
High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
General Description
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
the ground bus and 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/MAX1711 are identical except that the
MAX1711 have 5-bit DACs and the MAX1710 has 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.
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 Configurations appear 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 4-Bit On-Board DAC (MAX1710)
o 5-Bit On-Board DAC (MAX1711/MAX1712)
o 0.925V to 2V Output Adjust Range
(MAX1711/MAX1712)
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 Drive Large Synchronous-Rectifier FETs
o 2V ±1% Reference Output
o Power-Good Indicator
o Small 24-Pin QSOP Package
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
BATTERY
4.5V TO 28V
V_CC OVP* V_DD
SHDN
V+
FBS
ILIM
BST
DH
GNDS
MAX1710
MAX1711
REF _MAX1712 LX
CC
D0
D1
D/A
INPUTS
D2
D3
*MAX1710 ONLY
D4** _GND
**MAX1711/MAX1712 ONLY
DL
PGND
FB
SKIP
OUTPUT
0.925V TO 2V
(MAX1711/MAX1712)
________________________________________________________________ Maxim Integrated Products 1
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