LTC3822: Low Voltage Input DC/DC Controller Drives N-Channel MOSFETs, Delivering up to 20A

MILPITAS, CA – July 27, 2006 – Linear Technology Corporation introduces the LTC3822, a 2.75V to 4.5V input synchronous step-down DC/DC controller that drives N-channel MOSFETs without requiring an external supply for gate drive. In addition, the LTC3822 eliminates the need for a sense resistor by using MOSFET RDS(ON) sensing current, which improves efficiency and reduces solution cost. Although the LTC3822 drives N-channel MOSFETs, it is capable of operation at 99% duty cycle for very low dropout regulation. An adjustable operating frequency from 300kHz to 750kHz allows designers to size their systems, minimize noise interference and optimize efficiency. Applications include point-of-load conversion from 3.3VIN and portable devices with single Li-Ion batteries for up to 20A load current requirements.

The LTC3822 provides excellent line and load regulation as well as fast transient response with its constant frequency current mode operation. The output is adjustable from 0.6V to 99% of the input voltage. Internal soft-start circuitry guarantees controlled startup to minimize inrush current and ensure proper regulation. The LTC3822 consumes only 340uA during operation and only 7.5uA in shutdown.

The LTC3822 is offered in two packages a 10-lead MSOP and a smaller 3mm x 3mm DFN. It is rated for operation from -40ºC to 85ºC. 1,000-piece pricing is set at $2.10 each.

Summary of Features:  LTC3822

• Low VIN Operation: 2.75V to 4.5V
• No Sense Resistor Required
• Current Mode Operation
• Drives N-Channel MOSFETs
• 99% Duty Cycle (Low Dropout Operation)
• Supplies Up to 20A

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