LM3668_14 Datasheet, PDF (1/26 Pages) Texas Instruments – 1A, High Efficiency Dual Mode Single Inductor Buck-Boost DC/DC Converter

LM3668
www.ti.com
SNVS449L – JUNE 2007 – REVISED MARCH 2011
LM3668 1A, High Efficiency Dual Mode Single Inductor Buck-Boost DC/DC Converter
Check for Samples: LM3668
FEATURES
1
•2 45µA Typical Quiescent Current
• For 2.8V/3.3V and 3.0/3.4V Versions:
– 1A Maximum Load Current for
V_IN = 2.8V to 5.5V
– 800mA Maximum Load Current for
V_IN = 2.7V
– 600mA Maximum Load Current for
V_IN = 2.5V
• For 4.5/5V
– 1A Maximum Load Current for
V_IN = 3.9V to 5.5V
– 800mA Maximum Load Current for
V_IN = 3.4V to 3.8V
– 700mA Maximum Load Current for
V_IN = 3.0V to 3.3V
– 600mA Maximum Load Current for
V_IN = 2.7V to 2.9V
• 2.2MHz PWM Fixed Switching Frequency (typ.)
• Automatic PFM-PWM Mode or Forced PWM
Mode
• Wide Input Voltage Range: 2.5V to 5.5V
• Internal Synchronous Rectification for High
Efficiency
• Internal Soft Start: 600µs Maximum Startup
Time After V_IN Settled
• 0.01µA Typical Shutdown Current
• Current Overload and Thermal Shutdown
Protection
• Frequency Sync Pin: 1.6MHz to 2.7MHz
APPLICATIONS
• Handset Peripherals
• MP3 Players
• Pre-Regulation for Linear Regulators
• PDAs
• Portable Hard Disk Drives
• WiMax Modems
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
2.5V and 5.5V. It has the capability to support up to
1A 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 2.2MHz (typ.) is used. PWM mode drives
load up to 1A. Hysteretic PFM mode extends the
battery life through reduction of the quiescent current
to 45µA (typ.) at light loads during system standby.
Internal synchronous rectification provides high
efficiency. In shutdown mode (Enable pin pulled low)
the device turns off and reduces battery consumption
to 0.01µA (typ.).
The LM3668 is available in a 12-pin WSON package.
A high switching frequency of 2.2MHz (typ.) allows
the use of tiny surface-mount components including a
2.2µH inductor, a 10µF input capacitor, and a 22µF
output capacitor.
1
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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