LT1912 36V, 2A, 500kHz Step-Down Switching Regulator FEATURES DESCRIPTION Wide Input Range: Operation From 3.6V to 36V The LT 1912 is an adjustable frequency (200kHz to 500kHz) 2A Maximum Output Current monolithic step-down switching regulator that accepts Adjustable Switching Frequency: 200kHz to 500kHz input voltages up to 36V. A high efficiency 0.25 switch Low Shutdown Current: I < 1A is included on the die along with a boost Schottky diode Q Integrated Boost Diode and the necessary oscillator, control and logic circuitry. Synchronizable Between 250kHz to 500kHz Current mode topology is used for fast transient response Saturating Switch Design: 0.25 On-Resistance and good loop stability. The LT1912 allows the use of 0.790V Feedback Reference Voltage ceramic capacitors resulting in low output ripple while Output Voltage: 0.79V to 20V keeping total solution size to a minimum. The low current Soft-Start Capability shutdown mode reduces input supply current to less than Small 10-Pin Thermally Enhanced MSOP and 1A while a resistor and capacitor on the RUN/SS pin (3mm 3mm) DFN Packages provide a controlled output voltage ramp (soft-start). The LT1912 is available in 10-pin MSOP and 3mm 3mm DFN packages with exposed pads for low thermal resistance. APPLICATIONS L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the Automotive Battery Regulation property of their respective owners. Set-Top Box Distributed Supply Regulation Industrial Supplies Wall Transformer Regulation TYPICAL APPLICATION 3.3V Step-Down Converter Efficiency V IN V 100 OUT 4.5V TO 36V 3.3V 2A V = 5V OUT V BD IN 90 RUN/SS BOOST OFF ON V = 3.3V OUT 80 0.47F 6.8H 20k V SW C LT1912 4.7F 70 R T 470pF 60 316k V = 12V 68.1k SYNC IN FB GND L = 6.8F F = 500kHz 100k 47F 50 0 0.5 1.0 1.5 2 LOAD CURRENT (A) 1912 TA01b 1912 TA01 1912fa 1 EFFICIENCY (%)LT1912 ABSOLUTE MAXIMUM RATINGS (Note 1) Operating Junction Temperature Range (Note 2) V , RUN/SS Voltage .................................................36V IN LT1912E ............................................ 40C to 125C BOOST Pin Voltage ...................................................56V Storage Temperature Range .................. 65C to 150C BOOST Pin Above SW Pin .........................................30V Lead Temperature (Soldering, 10 sec) FB, RT, V Voltage .......................................................5V C MSE Only ..........................................................300C BD, SYNC Voltage .....................................................30V PIN CONFIGURATION TOP VIEW TOP VIEW BD 1 10 R T BD 1 10 R T BOOST 2 9 V C BOOST 2 9 V C 11 11 SW 3 8 FB SW 3 8 FB GND GND V 4 7 N/C IN V 4 7 N/C IN RUN/SS 5 6 SYNC RUN/SS 5 6 SYNC MSE PACKAGE 10-LEAD PLASTIC MSOP DD PACKAGE = 45C/W, = 10C/W JA JC 10-LEAD (3mm 3mm) PLASTIC DFN EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB = 45C/W, = 10C/W JA JC EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT1912EDD PBF LT1912EDD TRPBF LDJT 10-Lead (3mm 3mm) Plastic DFN 40C to 125C LT1912EMSE PBF LT1912EMSE TRPBF LTDJS 40C to 125C 10-Lead Plastic MSOP Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: