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LM3691
SNVS506J –MAY 2008–REVISED DECEMBER 2015
LM3691 High-Accuracy, Miniature 1-A Step-Down DC-DC Converter
for Portable Applications
1 Features
3 Description
The LM3691 step-down DC-DC converter is
optimized for powering ultra-low-voltage circuits from
a single Li-Ion cell or 3 cell NiMH/NiCd batteries. It
provides up to 1-A load current over an input voltage
range from 2.3 V to 5.5 V. There are several different
fixed voltage output options available.
1
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Input Voltage: 2.3 V to 5.5 V
Output Voltage: 0.75 V to 3.3 V
±1% DC Output Voltage Precision
4-MHz Switching Frequency
64-μA (typical) Quiescent Current in ECO Mode
1-A Maximum Load Capability
The LM3691 has a mode-control pin that allows the
user to select Forced PWM mode or ECO mode that
changes modes between gated PWM mode and
PWM automatically, depending on the load. In ECO
mode, the device offers superior efficiency and very
low IQ under light load conditions. ECO mode extends
the battery life through reduction of the quiescent
current during light load conditions and system
standby.
Automatic ECO/PWM Mode Switching
MODE Pin to Select ECO/Forced PWM Mode
Current Overload and Thermal Shutdown
Protections
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Only Three Tiny Surface-Mount External
Components Required (Solution Size Less Than
15 mm2)
The LM3691 is available in a 6-pin DSBGA package.
Only three external surface-mount components, a
1-μH inductor, a 4.7-μF input capacitor, and a 4.7-μF
output capacitor, are required.
2 Applications
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Mobile Phones
Hand-Held Radios
MP3 Players
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (MAX)
Portable Hard Disk Drives
LM3691
DSBGA (6)
1.59 mm × 1.295 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application Circuit
Efficiency vs. Output Current
(VOUT = 1.8 V, ECO Mode)
VIN
2.3 V to 5.5 V
VOUT
COUT
IN
EN
A2
B2
C1
B1
100
SW
FB
CIN
80
A1
C2
LM3691
V
= 2.3V
IN
60
40
20
0
GND
MODE
V
= 3.6V
IN
V
= 4.2V
IN
0.1
1
10
100
1000
OUTPUT CURRENT (mA)
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.