Features

• Wide Input Range: 3.6V to 34V Operating, 36V Maximum
• 2A Maximum Output Current
• Low Ripple Burst Mode® Operation
   50µA I_Q at 12V_IN to 3.3V_OUT
   Output Ripple < 15mV
• Adjustable Switching Frequency: 300kHz to 2.8MHz
• Low Shutdown Current: I_Q < 1µA
• Integrated Boost Diode
• Power Good Flag
• Saturating Switch Design: 0.18Ω On-Resistance
• 1.265V Feedback Reference Voltage
• Output Voltage: 1.265V to 20V
• Soft-Start Capability
• Synchronizable Between 275kHz to 475kHz
• Small 10-Pin Thermally Enhanced MSOP and (3mm x 3mm) DFN Packages

Typical Application

Description

The LT3481 is an adjustable frequency (300kHz to 2.8MHz) monolithic buck switching regulator that accepts input voltages up to 34V (36V maximum). A high efficiency 0.18Ω switch is included on the die along with a boost Schottky diode and the necessary oscillator, control, and logic circuitry. Current mode topology is used for fast transient response and good loop stability. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15mV in a typical application. In addition, the LT3481 can further enhance low output current efficiency by drawing bias current from the output when V_OUT is above 3V. Shutdown reduces input supply current to less than 1µA while a resistor and capacitor on the RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good flag signals when V_OUT reaches 90% of the programmed output voltage. The LT3481 is available in 10-Pin MSOP and 3mm x 3mm DFN packages with exposed pads for low thermal resistance.