1A, High Efficiency Dual Mode Single Inductor Buck-Boost DC/DC Converter - LM3668

LM3668 (ACTIVE)

1A, High Efficiency Dual Mode Single Inductor Buck-Boost DC/DC Converter

 

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.

Features

  • 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
      VIN = 2.8 V to 5.5 V
    • 800-mA Maximum Load Current for
      VIN = 2.7 V
    • 600-mA Maximum Load Current for
      VIN = 2.5 V
  • For 4.5 V-5 V
    • 1-A Maximum Load Current for
      VIN = 3.9 V to 5.5 V
    • 800-mA Maximum Load Current for
      VIN = 3.4 V to 3.8 V
    • 700-mA Maximum Load Current for
      VIN = 3 V to 3.3 V
    • 600-mA Maximum Load Current for
      VIN = 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 VIN Settled
  • 0.01-µA Typical Shutdown Current
  • Current Overload and Thermal Shutdown
    Protection
  • Frequency Sync Pin: 1.6 MHz to 2.7 MHz

View more

Parametrics Compare all products in Buck/Boost, Inverting or Split-Rail Converter (Integrated Switch)

 
Topology
Vin (Min) (V)
Vin (Max) (V)
Vout (Min) (V)
Vout (Max) (V)
Switch Current Limit (Typ) (A)
Switching Frequency (Min) (kHz)
Switching Frequency (Max) (kHz)
Iq (Typ) (mA)
Features
Operating Temperature Range (C)
Rating
Package Group
LM3668
Buck/Boost   
2.5   
5.5   
2.8   
5   
2.05   
1900   
2500   
0.045   
Frequency Synchronization
Light Load Efficiency   
-40 to 85   
Catalog   
WSON   

Other qualified versions of LM3668

Version Part Number Definition
Automotive LM3668-Q1 Q100 devices qualified for high-reliability automotive applications targeting zero defects

Featured tools and software

WEBENCH® Designer LM3668

  Min   Max Range
Vin  V 2.50 to 5.50V
Product Option
Vout  V
Iout  A 1A
Ambient Temp  °C -40 to 125°C


Footprint BOM Cost Efficiency