LTC3406B Datasheet

• High Efficiency: Up to 96%
• 600mA Output Current at V_IN = 3V
• 2.5V to 5.5V Input Voltage Range
• 1.5MHz Constant Frequency Operation
• No Schottky Diode Required
• Low Dropout Operation: 100% Duty Cycle
• Low Quiescent Current: 300µA
• 0.6V Reference Allows Low Output Voltages
• Shutdown Mode Draws <1µA Supply Current
• Current Mode Operation for Excellent Line and Load Transient Response
• Overtemperature Protected
• Low Profile (1mm) ThinSOT^™ Package

• Cellular Telephones
• Personal Information Appliances
• Wireless and DSL Modems
• Digital Still Cameras
• MP3 Players
• Portable Instruments

The LTC3406B is a high efficiency monolithic synchronous buck regulator using a constant frequency, current mode architecture. The device is available in an adjustable version and fixed output voltages of 1.5V and 1.8V. Supply current with no load is 300µA and drops to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3406B ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. PWM pulse skipping mode operation provides very low output ripple voltage for noise sensitive applications.

Switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors. The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Low output voltages are easily supported with the 0.6V feedback reference voltage. The LTC3406B is available in a low profile (1mm) ThinSOT package. Refer to LTC3406 for applications that require Burst Mode^® operation.