LT3682 1A Micropower Step-Down Switching Regulator FEATURES DESCRIPTION n Wide Input Range: The LT 3682 is an adjustable frequency (250kHz to Operation from 3.6V to 36V 2.2MHz) monolithic buck switching regulator that accepts Overvoltage Lockout Protects Circuits through input voltages up to 36V. A high ef ciency 0.5 switch is 60V Transients included on the device along with a boost diode and the n 1A Output Current necessary oscillator, control, and logic circuitry. Current n Low Ripple Burst Mode Operation mode topology is used for fast transient response and good I = 75A at 12V to 3.3V loop stability. A SYNC pin allows the user to synchronize the Q IN OUT Output Ripple < 15mV part to an external clock, and to choose between Low Ripple P-P n Adjustable Switching Frequency: 250kHz to 2.2MHz Burst Mode operation and standard PWM operation. n Short-Circuit Protected The Low Ripple Burst Mode maintains high ef ciency at n Synchronizable Between 300kHz and 2.2MHz low output currents while keeping output ripple below n 0.8V Feedback Reference Voltage 15mV in typical applications. Shutdown reduces input n Output Voltage 0.8V to 20V supply current to less than 1A while a resistor and n Soft-Start Capability capacitor on the RUN/SS pin provide a controlled output n Power Good Flag voltage ramp (soft-start). A power good ag signals when n Small 12-Pin Thermally Enhanced 3mm 3mm V reaches 90% of the programmed output voltage. OUT DFN Package Protection circuitry senses the current in the power switch and external Schottky catch diode to protect the LT3682 against short-circuit conditions. Frequency foldback and APPLICATIONS thermal shutdown provide additional protection. n Automotive Battery Regulation The LT3682 is available in a 12-Pin 3mm 3mm DFN with n Automotive Entertainment Systems exposed pad for low thermal resistance. n Industrial Supplies L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode n Power for Portable Products is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Distributed Supply Regulation TYPICAL APPLICATION 5V Step-Down Converter Ef ciency V OUT 100 V IN 5V 6.9V TO 36V 0.9A, V r 6.9V IN V = 5V OUT TRANSIENT TO 60V 1A, V r 12V IN 90 V BD IN V = 3.3V ON OFF RUN/SS BOOST OUT 80 0.22F V C 2.2F 10H LT3682 SW 70 R T 16.2k PG DA 536k 60 V = 12V 40.2k IN SYNC FB L = 10H GND PGND 470pF f = 800 kHz 102k 10F 50 0 0.2 0.4 0.6 0.8 1 3682 TA01 LOAD CURRENT (A) f = 800kHz 3682 TA01b 3682f 1 EFFICIENCY (%)LT3682 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , RUN/SS Voltage (Note 2) ....60V IN V 1 12 V IN C BOOST Pin Voltage ... 50V FB 2 11 SYNC BOOST Pin Above SW Pin ..30V 3 10 R PG T 13 FB, R , V Voltage ......................................................5V 4 9 GND RUN/SS T C 5 8 BD SW SYNC ... 20V 6 7 DA BOOST BD and PG Voltage ....... 30V DD PACKAGE Operating Junction Temperature Range (Notes 3 and 6) 12-LEAD (3mm s 3mm) PLASTIC DFN LT3682E ..40C to 125C = 43C/W JA EXPOSED PAD (PIN 13) IS PGND, MUST BE SOLDERED TO PCB LT3682I . 40C to 125C Storage Temperature Range .. 65C to 150C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3682EDD PBF LT3682EDD TRPBF LFDW 40C to 125C 12-Lead (3mm 3mm) Plastic DFN LT3682IDD PBF LT3682IDD TRPBF LFDW 40C to 125C 12-Lead (3mm 3mm) Plastic DFN Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: