LT3684 36V, 2A, 2.8MHz Step-Down Switching Regulator FEATURESDESCRIPTION n Wide Input Range: 3.6V to 34V Operating, The LT®3684 is an adjustable frequency (300kHz to 2.8MHz) 36V Maximum monolithic buck switching regulator that accepts input n 2A Maximum Output Current voltages up to 34V (36V maximum). A high efficiency n Adjustable Switching Frequency: 300kHz to 2.8MHz 0.18Ω switch is included on the die along with a boost n Low Shutdown Current: I Schottky diode and the necessary oscillator, control and Q < 1µA n Integrated Boost Diode logic circuitry. Current mode topology is used for fast n Power Good Flag transient response and good loop stability. The LT3684’s n Saturating Switch Design: 0.18Ω On-Resistance high operating frequency allows the use of small, low cost n 1.265V Feedback Reference Voltage inductors and ceramic capacitors resulting in low output n Output Voltage: 1.265V to 20V ripple while keeping total solution size to a minimum. n Soft-Start Capability The low current shutdown mode reduces input supply n Small 10-Pin Thermally Enhanced MSOP and current to less than 1µA while a resistor and capacitor on (3mm × 3mm) DFN Packages the RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good flag signals when VOUT reaches 90% of the programmed output voltage. The LT3684 is APPLICATIONS available in 10-Pin MSOP and 3mm × 3mm DFN packages n with Exposed Pads for low thermal resistance. Automotive Battery Regulation n Power for Portable Products L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Distributed Supply Regulation n Industrial Supplies n Wall Transformer Regulation TYPICAL APPLICATION3.3V Step-Down ConverterEfficiency VIN 4.5V TO VOUT 90 34V 3.3V V 2A IN BD 80 OFF ON RUN/SS BOOST 0.47µF 16.2k 4.7µH 70 VC SW 4.7µF LT3684 RT 60 330pF PG BIAS EFFICIENCY (%) 324k 50 60.4k FB GND VIN = 12V 200k 22µF 40 VOUT = 3.3V L = 4.7µH f = 800kHz 30 3684 TA01a 0 0.5 1 1.5 2 LOAD CURRENT (A) 3684 TA01b 3684fa For more information www.linear.com/LT3684 1