LM3668_15 Datasheet, PDF (1/30 Pages) Texas Instruments – 1-A, High-Efficiency Dual-Mode Single-Inductor Buck-Boost DC-DC Converter

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LM3668
SNVS449O – JUNE 2007 – REVISED APRIL 2015
LM3668 1-A, High-Efficiency Dual-Mode Single-Inductor Buck-Boost DC-DC Converter
1 Features
•1 45-µA Typical Quiescent Current
• For 2.8-V-3.3-V and 3-V-3.4-V Versions:
– 1-A Maximum Load Current for
V_IN = 2.8 V to 5.5 V
– 800-mA Maximum Load Current for
V_IN = 2.7 V
– 600-mA Maximum Load Current for
V_IN = 2.5 V
• For 4.5 V-5 V
– 1-A Maximum Load Current for
V_IN = 3.9 V to 5.5 V
– 800-mA Maximum Load Current for
V_IN = 3.4 V to 3.8 V
– 700-mA Maximum Load Current for
V_IN = 3 V to 3.3 V
– 600-mA Maximum Load Current for
V_IN = 2.7 V to 2.9 V
• 2.2-MHz PWM Fixed Switching Frequency
(Typical)
• Automatic PFM-PWM Mode or Forced PWM
Mode
• Wide Input Voltage Range: 2.5 V to 5.5 V
• Internal Synchronous Rectification for High
Efficiency
• Internal Soft Start: 600-µs Maximum Start-Up
Time After V_IN Settled
• 0.01-µA Typical Shutdown Current
• Current Overload and Thermal Shutdown
Protection
• Frequency Sync Pin: 1.6 MHz to 2.7 MHz
Typical Application Circuit
VIN = 2.5V - 5.5V
C1
10 2F
2.2 2H
VDD
SW1
PVIN
VOUT
LM3668 ^FB
SW2 SYNC/MODE
EN
VSEL
NC _{SGND PGND}
L = 2.8V
H = 3.3V
2.8V/3.3V
C2
22 2F
2 Applications
• Handset Peripherals
• MP3 Players
• Pre-Regulation for Linear Regulators
• PDAs
• Portable Hard Disk Drives
• WiMax Modems
3 Description
The LM3668 is a synchronous buck-boost DC-DC
converter optimized for powering low voltage circuits
from a Li-Ion battery and input voltage rails between
2.5 V and 5.5 V. It has the capability to support up to
1-A output current over the output voltage range. The
LM3668 regulates the output voltage over the
complete input voltage range by automatically
switching between buck or boost modes depending
on the input voltage.
The LM3668 has 2 N-channel MOSFETS and 2 P-
channel MOSFETS arranged in a topology that
provides continuous operation through the buck and
boost operating modes. There is a MODE pin that
allows the user to choose between an intelligent
automatic PFM-PWM mode operation and forced
PWM operation. During PWM mode, a fixed-
frequency 2.2 MHz (typical) is used. PWM mode
drives load up to 1 A. Hysteretic PFM mode extends
the battery life through reduction of the quiescent
current to 45 µA (typical) at light loads during system
standby. Internal synchronous rectification provides
high efficiency. In shutdown mode (EN pin pulled
low), the device turns off and reduces battery
consumption to 0.01 µA (typical).
A high switching frequency of 2.2 MHz (typical)
allows the use of tiny surface-mount components
including a 2.2-µH inductor, a 10-µF input capacitor,
and a 22-µF output capacitor.
Device Information⁽¹⁾
PART NUMBER PACKAGE
BODY SIZE (NOM)
LM3668
WSON (12)
3.00 mm x 3.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
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.