19-0224; Rev 2; 8/94
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5V-to-3.3V, Synchronous, Step-Down
Power-Supply Controller
____________________________Features
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>90% Efficiency
700µA Quiescent Supply Current
120µA Standby Supply Current
4.5V-to-5.5V Input Range
Low-Cost Application Circuit
All N-Channel Switches
Small External Components
Tiny Shrink-Small-Outline Package (SSOP)
Predesigned Applications:
Standard 5V to 3.3V DC-DC Converters up to 10A
High-Accuracy Pentium P54C VR-Spec Supply
o
Fixed Output Voltages Available:
3.3V (Standard)
3.45V (High-Speed Pentium™)
3.6V (PowerPC™)
_______________General Description
The MAX767 is a high-efficiency, synchronous buck
controller IC dedicated to converting a fixed 5V supply
into a tightly regulated 3.3V output. Two key features set
this device apart from similar, low-voltage step-down
switching regulators: high operating frequency and all
N-channel construction in the application circuit. The
300kHz operating frequency results in very small, low-
cost external surface-mount components.
The inductor, at 3.3µH for 5A, is physically at least five
times smaller than inductors found in competing solu-
tions. All N-channel construction and synchronous rectifi-
cation result in reduced cost and highest efficiency.
Efficiency exceeds 90% over a wide range of loading,
eliminating the need for heatsinking. Output capacitance
requirements are low, reducing board space and cost.
The MAX767 is a monolithic BiCMOS IC available in
20-pin SSOP packages. For other fixed output voltages
and package options, please consult the factory.
MAX767
______________Ordering Information
PART
MAX767CAP
MAX767RCAP
MAX767SCAP
MAX767TCAP
MAX767C/D
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
PIN-
PACKAGE
20 SSOP
20 SSOP
20 SSOP
20 SSOP
Dice*
REF.
TOL.
V
OUT
________________________Applications
Local 5V-to-3.3V DC-DC Conversion
Microprocessor Daughterboards
Power Supplies up to 10A or More
±1.8% 3.3V
±1.8% 3.45V
±1.8% 3.6V
±1.2% 3.3V
–
–
________Typical Application Circuit
INPUT
4.5V TO 5.5V
Ordering Information continued at end of data sheet.
*
Contact factory for dice specifications.
__________________Pin Configuration
TOP VIEW
V
CC
ON
BST
DH
OUTPUT
3.3V
AT 5A
CS
1
SS
2
ON
3
GND
4
DL
GND
5
GND
6
GND
7
REF
8
SYNC
9
V
CC
10
20
FB
19
DH
18
LX
3.3µH
MAX767
LX
MAX767
17
BST
16
DL
15
V
CC
14
V
CC
13
PGND
12
N.C.
11
GND
PGND
CS
FB
REF
GND
SSOP
™ Pentium is a trademark of Intel.
PowerPC is a trademark of IBM.
1
________________________________________________________________
Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
