LM3668SD-2833

• Product Introduction

The LM3668 is a synchronous buck-boost DC-DC converter optimized for driving low-voltage circuits from lithium-ion batteries, input voltage rails between 2.5V and 5.5V. It has the ability to support output current over an output voltage range of 1A. The LM3668 regulates the output voltage of different switches for the input voltage in automatic buck or boost mode over the entire input voltage range.

The LM3668 evaluation board is a working demonstration of a synchronous buck-boost DC-DC converter. This application note contains information about evaluating the board. For more details and the electrical characteristics of the converter operation, please refer to the table.

Peculiarity:

• 45μ typical quiescent current
• For 2.8V/3.3V and 3.0/3.4V versions:
  - 1A maximum load current is V IN = 2.8V to 5.5V
  - 800 mA maximum load current is V IN = 2.7V
  - 600 mA maximum load current is V IN = 2.5V
• For 4.5/5V
  - 1A maximum load current is V IN = 3.9V to 5.5V
  - 800 mAh maximum load current is V IN = 3.4V to 3.8V
  - 700 mA maximum load current is V IN = 3.0V to 3.3V
  - 600 mA maximum load current is V IN = 2.7V to 2.9V
• 2.2MHz Fixed Switching Frequency PWM (Typical)
• Automatic PFM - PWM mode or forced PWM mode
• Wide input voltage range: 2.5V to 5.5V
• Internally synchronized rectification for high efficiency
• Internal Soft Start: 600μs after maximum start-up at the settlement V time.
• 0.01μ typical shutdown current
• Current overload and thermal shutdown protection
• Frequency Sync Pins: 1.6MHz to 2.7MHz

Applications:

• Mobile phone peripherals
• MP3 player
• Pre-regulated linear regulator
• handheld computer
• Portable hard drives
• WiMAX modem