peculiarity
45μA typical quiescent current
2.8V/3.3V and 3.0/3.4V versions:
- 1A maximum load current is V = 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 = 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
Fixed PWM switching frequency at 2.2MHz (typical)
Automatic PFM - PWM mode or forced PWM mode
Wide input voltage range: 2.5V to 5.5V
Efficient internal synchronous rectification
Internal soft start-up: up to 600μs start-up time in V settlement
0.01μA typical shutdown current
Current overload and thermal shutdown protection
Frequency Sync Pins: 1.6MHz to 2.7MHz
illustrate
The LM3668 is a synchronous buck-boost DC-DC converter optimized for low-voltage circuits powered from lithium-ion batteries, input voltage rails between 2.5V and 5.5V. It has the ability to support an output current of more than 1A, an output voltage range. The LM3668 regulates the output voltage over the entire input voltage range, automatically switching between buck or boost modes depending on the input voltage.
The LM3668 has a topology of 2 N-channel MOSFETs and 2 P-channel MOSFETs to provide continuous operation through step-down and improve the operating mode arrangement. There is a MODE pin that allows the user to choose between intelligent automatic PFM - PWM mode operation and forced PWM operation. In PWM mode, the fixed frequency is 2.2MHz (typical). PWM mode drives loads up to 1A. Hysteresis PFM mode extends the quiescent current reduced by battery life to 45μA (typical) at light load and standby in the system. Internal synchronous rectification provides high efficiency. The device shuts off in shutdown mode (enable pin pulled down), reducing battery consumption by 0.01μA (typical).
The LM3668 is available in a 12-pin LLP package. A high switching frequency of 2.2MHz (typical) allows for the use of tiny surface-mount components, including a 2.2μH inductor, a 10μF input capacitor, and a 22μF output capacitor.
apply
Mobile phone peripherals
MP3 player
Preconditioning of linear regulators
handheld computer
Portable hard drives
WiMAX modem