MAX1761 Datasheet, PDF (1/23 Pages) Maxim Integrated Products – Small, Dual, High-Efficiency Buck Controller for Notebooks

19-1835; Rev 0; 10/00
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Small, Dual, High-Efficiency
Buck Controller for Notebooks
General Description
The MAX1761 dual pulse-width-modulation (PWM),
step-down controller provides high efficiency, excellent
transient response, and high DC output accuracy in an
extremely compact circuit topology. These features are
essential for stepping down high-voltage batteries to
generate low-voltage CPU core, I/O, and chipset RAM
supplies in PC board area critical applications, such as
notebook computers and smart phones.
Maxim’s proprietary Quick-PWM™ quick-response,
constant-on-time PWM control scheme handles wide
input/output voltage ratios with ease and provides
“instant-on” response to load transients while maintain-
ing a relatively constant switching frequency.
The MAX1761 achieves high efficiency at reduced cost
by eliminating the current-sense resistor found in tradi-
tional current-mode PWMs. Efficiency is further
enhanced by its ability to drive large synchronous-recti-
fier MOSFETs. The MAX1761 employs a complemen-
tary MOSFET output stage, which reduces component
count by eliminating external bootstrap capacitors and
diodes.
Single-stage buck conversion allows this device 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
battery) at a higher switching frequency allows the mini-
mum possible physical size.
The MAX1761 is intended for CPU core, chipset,
DRAM, or other low-voltage supplies. The MAX1761 is
available in a 16-pin QSOP package. For applications
requiring greater output power, refer to the MAX1715
data sheet. For a single-output version, refer to the
MAX1762/MAX1791 data sheet.
________________________Applications
Notebooks and PDAs
Digital Cameras
Handy-Terminals
Smart Phones
1.8V/2.5V Logic and I/O Supplies
Quick-PWM and Dual Mode are trademarks of
Maxim Integrated Products.
Features
o Free-Running On-Demand PWM
o Selectable Light-Load Pulse-Skipping Operation
o ±1% Total DC Error in Forced-PWM Mode
o 5V to 20V Input Range
o Flexible Output Voltages
OUT1: Dual Mode™ Fixed 2.5V or 1V to 5.5V
Adjustable
OUT2: Dual Mode Fixed 1.8V or 1V to 5.5V
Adjustable
o Output Undervoltage Protection
o Complementary Synchronous Buck
o No Current-Sense Resistor
o 4.65V at 25mA Linear Regulator Output
o 4µA V+ Shutdown Supply Current
o 5µA VL Shutdown Supply Current
o 950µA Quiescent Supply Current
o Tiny 16-Pin QSOP Package
PART
MAX1761EEE
Ordering Information
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
16 QSOP
Pin Configuration
TOP VIEW
FB1 1
OUT1 2
REF 3
ON2 4
V+ 5
ON1 6
OUT2 7
FB2 8
MAX1761
QSOP
16 DH1
15 CS1
14 DL1
13 VL
12 GND
11 DL2
10 CS2
9 DH2
________________________________________________________________ Maxim Integrated Products 1
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.