LT3685 Datasheet | Analog Devices

Features n Wide Input Range: Operation From 3.6V to 36V Overvoltage Lockout Protects Circuit through 60V Transients n 2A Maximum Output Current n Adjustable Switching Frequency: 200k Hz to 2.4MHz n Low Shutdown Current: IQ < 1µA n Integrated Boost Diode n Synchronizable Between 250k Hz to 2MHz n Power Good Flag n Saturating Switch Design: 0.25 On-Resistance n 0.790V Feedback Reference Voltage n Output Voltage: 0.79V to 20V n Soft-Start Capability n Small 10-Pin Thermally Enhanced MSOP and (3mm × 3mm) DFN Packages APPLICATIONS n Automotive Battery Regulation n Set Top Box n Distributed Supply Regulation n Industrial Supplies n Wall Transformer Regulation DESCRIPTION The LT®3685 is an adjustable frequency (200k Hz to 2.4MHz) monolithic step-down switching regulator that accepts input voltages up to 38V operating and 60V maximum. An internal overvoltage protection circuit turns off the power switch when VIN is above 38V typical (36V minimum) which then allows the part to safely withstand 60V transients. A high efficiency 0.25 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. The LT3685’s high operating frequency allows the use of small, low cost inductors and ceramic capacitors resulting in low output ripple while keeping total solution size to a minimum. The low current shutdown mode 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 VOUT reaches 89% of the programmed output voltage. The LT3685 is available in 10-Pin MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance. All registered trademarks and trademarks are the property of their respective owners. TYPICAL APPLICATION 3.3V Step-Down Converter VIN 4.5V TO 36V TRANSIENT TO 60V OFF ON 14k 4.7µF 470p...