19-1400; Rev 0; 11/98
NUAL
KIT MA
ATION
ET
EVALU
TA SHE
WS DA
FOLLO
Low-Noise, 5.5V-Input,
PWM Step-Down Regulator
Features
o
+2.7V to +5.5V Input Range
o
Adjustable Output from 1.25V to V
IN
o
600mA Guaranteed Output Current
o
95% Efficiency
o
No Schottky Diode Required
o
85µA Quiescent Current
o
100% Duty Cycle in Dropout
o
750kHz Fixed-Frequency PWM Operation
o
Synchronizable Switching Frequency
o
Accurate Reference: 1.25V (±1.2%)
o
Small 10-Pin µMAX Package
General Description
The MAX1692 is a low-noise, pulse-width-modulated
(PWM), DC-DC step-down converter. It powers logic
and transmitters in small wireless systems such as cellu-
lar phones, communicating PDAs, and handy-terminals.
The device features an internal synchronous rectifier for
high efficiency; it requires no external Schottky diode.
Excellent noise characteristics and fixed-frequency
operation provide easy post-filtering. The MAX1692 is
ideally suited for Li-Ion battery applications. It is also
useful for +3V or +5V fixed input applications.
The device operates in one of four modes. Forced PWM
mode operates at a fixed frequency regardless of the
load. Synchronizable PWM mode allows an external
switching frequency to control and minimize harmonics.
Idle Mode™ (PWM/PFM) extends battery life by switch-
ing to a PFM pulse-skipping mode during light loads.
Shutdown mode places the device in standby, reduc-
ing quiescent supply current to under 0.1µA.
The MAX1692 can deliver over 600mA. The output volt-
age can be adjusted from 1.25V to V
IN
with the input
range of +2.7V to +5.5V. Other features of the
MAX1692 include high efficiency, low dropout voltage,
and a 1.2%-accurate 1.25V reference. It is available in
a space-saving 10-pin µMAX package with a height of
only 1.11mm.
MAX1692
Ordering Information
PART
MAX1692EUB
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
10 µMAX
Pin Configuration
TOP VIEW
IN
1
BP
GND
REF
FB
2
3
4
5
10
PGND
9
LX
SHDN
SYNC/PWM
LIM
Applications
Cellular Phones
Cordless Phones
CPU I/O Supplies
Notebook Chipset Supplies
MAX1692
8
7
6
PDAs and Handy-Terminals Battery-Operated Devices
(1 Li-Ion or 3 NiMH/NiCd)
µMAX
Typical Operating Circuit
L
V
IN
= 2.7V TO 5.5V
C1
IN
SHDN
LIM
R1
LX
C2
V
OUT
= 1.25V TO V
IN
MAX1692
BP
C3
AGND
REF
FB
R2
SYNC/PWM
PGND
C4
Idle Mode is a trademark of Maxim Integrated Products.
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
