Rainbow Electronics MAX1541 - Manual

General Description
The MAX1540/MAX1541 dual pulse-width modulation
(PWM) controllers provide the high efficiency, excellent
transient response, and high DC-output accuracy nec-
essary for stepping down high-voltage batteries to gen-
erate low-voltage chipset and RAM power supplies in
notebook computers.
The Maxim proprietary Quick-PWM™ controllers are
free running, constant on-time with input feed forward.
This configuration provides ultra-fast transient
response, wide input-output (I/O) differential range, low
supply current, and tight load-regulation characteris-
tics. The controllers can accurately sense the inductor
current across an external current-sense resistor in
series with the output to ensure reliable overload and
inductor saturation protection. Alternatively, the con-
trollers can use the synchronous rectifier itself or loss-
less inductor current-sensing methods to provide
overload protection with lower power dissipation.
For a single step-down PWM controller with inductor-
saturation protection, external-reference input voltage,
and dynamically selectable output voltages, refer to the
MAX1992/MAX1993 data sheet.
Applications
Notebook Computers
Core/IO Supplies as Low as 0.7V
0.7V to 5.5V Supply Rails
CPU/Chipset/GPU with Dynamic Voltage Core
Supplies (MAX1541)
DDR Memory Termination (MAX1541)
Active Termination Buses (MAX1541)
Features
♦ Inductor-Saturation Protection
♦ Accurate Differential Current-Sense Inputs
♦ Dual Ultra-High-Efficiency Quick-PWMs with
100ns Load-Step Response
♦ MAX1540
1.8V/1.2V Fixed or 0.7V to 5.5V Adjustable
Output (OUT1)
2.5V/1.5V Fixed or 0.7V to 5.5V Adjustable
Output (OUT2)
Fixed 5V, 100mA Linear Regulator
♦ MAX1541
External Reference Input (REFIN1)
Dynamically Selectable Output Voltage—0.7V
to 5.5V (OUT1)
2.5V/1.8V Fixed or 0.7V to 5.5V Adjustable
Output (OUT2)
Optional Power-Good and Fault Blanking
During Transitions
Fixed 5V or Adjustable 100mA Linear Regulator
♦ 1% V
OUT Accuracy over Line and Load
♦ 2V to 28V Battery Input Range
♦ 170kHz to 620kHz Selectable Switching
Frequency
♦ Overvoltage/Undervoltage-Protection Option
♦ 1.7ms Digital Soft-Start
♦ Drives Large Synchronous-Rectifier FETs
♦ 2V ±0.7% Reference Output
♦ Separate Power-Good Window Comparators
MAX1540/MAX1541
Dual Step-Down Controllers with Saturation
Protection, Dynamic Output, and Linear Regulator
________________________________________________________________ Maxim Integrated Products 1
THIN QFN
TOP VIEW
32 31 30 29 28 27 26
ON1 ON2 CSP1 CSN1 FB1 OUT1 PGOOD1
25
DH1
9 10 11 12 13 14 15
CSP2 CSN2
FB2
OUT2
PGOOD2
DH2 LX2
16
BST2
17
18
19
20
21
22
23
GND
DL2
V+
LDOOUT
DL1
LDOON
BST1
8
7
6
5
4
3
2
REF
ILIM2
ILIM1
V CC
TON
LSAT
SKIP
MAX1540
1 OVP/UVP 24 LX1
Pin Configurations
19-2861; Rev 0; 10/03
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.
EVALUATION KIT
AVAILABLE
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
*Future product—contact factory for availability.
Ordering Information
PART TEMP RANGE PIN-PACKAGE
MAX1540ETJ -40 °C to +85°C 32 Thin QFN 5mm x 5mm
MAX1541ETL* -40 °C to +85°C 40 Thin QFN 6mm x 6mm
Pin Configurations continued at end of data sheet.