LM3668SD-2833

• Product introduction

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

The LM3668 evaluation board is a synchronous buck-boost DC-DC converter in operation. This application note contains information about the evaluation board. For more details and the electrical characteristics of 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 mA 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)
• Auto 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 after maximum start-up,_atSettlement V time.
• 0.01μ typical shutdown current
• Current overload and thermal shutdown protection
• Frequency synchronization pin: 1.6MHz to 2.7MHz

Scope of application:

• Mobile phone perimeter
• MP3 player
• Pre-regulated linear regulator
• Pocket PC
• Portable hard drives
• WiMAX modem