Rainbow Electronics MAX1712 - Manual

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
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
♦ 4-Bit On-Board DAC (MAX1710)
♦ 5-Bit On-Board DAC (MAX1711/MAX1712)
♦ 0.925V to 2V Output Adjust Range
(MAX1711/MAX1712)
♦ 2V to 28V Battery Input Range
♦ 200/300/400/550kHz Switching Frequency
♦ Remote GND and V
OUT Sensing
♦ Over/Undervoltage Protection
♦ 1.7ms Digital Soft-Start
♦ Drive Large Synchronous-Rectifier FETs
♦ 2V ±1% Reference Output
♦ Power-Good Indicator
♦ Small 24-Pin QSOP Package
MAX1710/MAX1711/MAX1712
High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
________________________________________________________________ Maxim Integrated Products 1
19-4781; Rev 1; 7/00
Pin Configurations appear at end of data sheet.
Quick-PWM is a trademark of Maxim Integrated Products.
Mobile Pentium II is a registered trademark of Intel Corp.
-40°C to +85°C
PART
MAX1710EEG
TEMP. RANGE PIN-PACKAGE
24 QSOP
Ordering Information
MAX1711EEG -40°C to +85°C 24 QSOP
SKIP
GND
DH
LX
DL
BST
+5V INPUT
ILIM
GNDS
FBS
D0
D1
D2
D3
D4**
*MAX1710 ONLY
**MAX1711/MAX1712 ONLY
REF
CC
PGND
FB
MAX1710
MAX1711
MAX1712
V+
V CC OVP* V DD
SHDN
OUTPUT
0.925V TO 2V
(MAX1711/MAX1712)
D/A
INPUTS
BATTERY
4.5V TO 28V
Minimal Operating Circuit
EVALU
ATION
KIT
AVAILA
BLE
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.