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OUTPUT CURRENT (mA)
EFFICIENCY (%)
100
80
60
40
20
0
0.1 1 10 100 1000
V
IN
= 3.6V
V
IN
= 2.3V
V
IN
= 4.2V
LM3691
EN
B2
GND
MODE
A2
V
IN
V
OUT
C
OUT
IN
A1
SW
C1
FB
2.3 V to 5.5 V
C
IN
C2
B1
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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
1
• Input Voltage: 2.3 V to 5.5 V
optimized for powering ultra-low-voltage circuits from
• Output Voltage: 0.75 V to 3.3 V
a single Li-Ion cell or 3 cell NiMH/NiCd batteries. It
• ±1% DC Output Voltage Precision
provides up to 1-A load current over an input voltage
range from 2.3 V to 5.5 V. There are several different
• 4-MHz Switching Frequency
fixed voltage output options available.
• 64-μA (typical) Quiescent Current in ECO Mode
The LM3691 has a mode-control pin that allows the
• 1-A Maximum Load Capability
user to select Forced PWM mode or ECO mode that
• Automatic ECO/PWM Mode Switching
changes modes between gated PWM mode and
• MODE Pin to Select ECO/Forced PWM Mode
PWM automatically, depending on the load. In ECO
mode, the device offers superior efficiency and very
• Current Overload and Thermal Shutdown
low I
Q
under light load conditions. ECO mode extends
Protections
the battery life through reduction of the quiescent
• Only Three Tiny Surface-Mount External
current during light load conditions and system
Components Required (Solution Size Less Than
standby.
15 mm
2
)
The LM3691 is available in a 6-pin DSBGA package.
Only three external surface-mount components, a
2 Applications
1-μH inductor, a 4.7-μF input capacitor, and a 4.7-μF
• Mobile Phones
output capacitor, are required.
• Hand-Held Radios
Device Information
(1)
• MP3 Players
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
(V
OUT
= 1.8 V, ECO Mode)
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.
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