LM3668-Q1_15 Datasheet, PDF (1/24 Pages) Texas Instruments – 1A, High-Efficiency Dual-Mode Single-Inductor Buck-Boost DC-DC Converter

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LM3668-Q1
SNVSA84A – APRIL 2015 – REVISED MAY 2015
LM3668-Q1 1-A, High-Efficiency Dual-Mode Single-Inductor Buck-Boost DC-DC Converter
1 Features
•1 45-µA Typical Quiescent Current
• Output Voltage Option 4.5 V or 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: 2.7 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 = 2.7 V  5.5 V
C1
10 µF
VDD
PVIN
VOUT
2.2 µH
SW1
FB
LM3668-Q1
SW2
SYNC/MODE
EN
VSEL
NC
SGND
PGND
L = 4.5 V
H=5V
4.5 V/5 V
C2
22 µF
2 Applications
• Automotive Radar
• Automotive Camera
• Automotive Lidar
3 Description
The LM3668-Q1 is a synchronous buck-boost DC-DC
converter optimized for automotive requirements and
input voltage rails between 2.7 V and 5.5 V. It has the
capability to support up to 1-A output current over the
output voltage range. The LM3668-Q1 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-Q1 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-Q1
WSON (12)
4.00 mm x 4.00 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.