LT8613 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3A Quiescent Current FEATURES DESCRIPTION n Rail-to-Rail Current Sense Amplifier with Monitor The LT 8613 is a compact, high efficiency, high speed n Wide Input Voltage Range: 3.4V to 42V synchronous monolithic step-down switching regulator n Ultralow Quiescent Current Burst Mode Operation: that consumes only 3A of quiescent current. Top and n 3A I Regulating 12V to 3.3V bottom power switches are included with all necessary Q IN OUT n Output Ripple < 10mV circuitry to minimize the need for external components. P-P n High Efficiency Synchronous Operation: The built-in current sense amplifier with monitor and con- n 95% Efficiency at 3A, 5V from 12V trol pins allows accurate input or output current regulation OUT IN n 94% Efficiency at 3A, 3.3V from 12V and limiting. Low ripple Burst Mode operation enables OUT IN n Fast Minimum Switch-On Time: 40ns high efficiency down to very low output currents while n Low Dropout Under All Conditions: 250mV at 3A keeping the output ripple below 10mV . A SYNC pin P-P n Allows Use of Small Inductors allows synchronization to an external clock. Internal com- n Low EMI pensation with peak current mode topology allows the use n Adjustable and Synchronizable: 200kHz to 2.2MHz of small inductors and results in fast transient response n Current Mode Operation and good loop stability. The EN/UV pin has an accurate n Accurate 1V Enable Pin Threshold 1V threshold and can be used to program V undervolt- IN n Internal Compensation age lockout or to shut down the LT8613 reducing the n Output Soft-Start and Tracking input supply current to 1A. A capacitor on the TR/SS pin n Small Thermally Enhanced 3mm 6mm 28-Lead programs the output voltage ramp rate during start-up. QFN Package The PG flag signals when V is within 9% of the pro- OUT grammed output voltage as well as fault conditions. The APPLICATIONS LT8613 is available in a small 28-lead 3mm 6mm QFN package with exposed pad for low thermal resistance. n Automotive and Industrial Supplies All registered trademarks and trademarks are the property of their respective owners. n General Purpose Step-Down n CCCV Power Supplies TYPICAL APPLICATION Efficiency at 5V OUT 5V Step-Down Converter with 6A Output Current Limit 100 V V = 12V IN IN V BST IN 5.8V TO 42V 95 10F 0.1F ON OFF EN/UV V = 24V IN 3.9H 8m V 90 OUT SYNC SW 5V LT8613 1F 6A 85 IMON ISP ICTRL 80 ISN BIAS 75 10pF PG INTV 70 CC TR/SS 65 f = 700kHz 1M SW 10F RT FB L = 3.9H PGND GND 60 1F 60.4k 243k 100F 0 1 2 3 4 5 6 LOAD CURRENT (A) 8613 TA01a f = 700kHz 8613 TA01b SW L: EPCOS B82559 Rev. A 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT8613 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , EN/UV, PG, ISP, ISN ...........................................42V IN BIAS ..........................................................................25V 28 27 26 25 BST Pin Above SW Pin................................................4V SYNC 1 24 FB FB, TR/SS, RT, INTV , IMON, ICTRL.......................4V CC TR/SS 2 23 PG SYNC Voltage ...........................................................6V RT 3 22 BIAS EN/UV 4 21 INTV Operating Junction Temperature Range (Note 2) CC V 5 20 BST IN 29 LT8613E ............................................. 40C to 125C GND V 6 19 SW IN LT8613I .............................................. 40C to 125C V 7 18 SW IN Storage Temperature Range .................. 65C to 150C 8 PGND 17 SW PGND 9 16 SW PGND 10 15 SW 11 12 13 14 UDE PACKAGE 28-LEAD (3mm 6mm) PLASTIC QFN = 40C/W, = 5C/W JA JC(PAD) EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT8613EUDE PBF LT8613EUDE TRPBF LGHX 28-Lead (3mm 6mm) Plastic QFN 40C to 125C LT8613IUDE PBF LT8613IUDE TRPBF LGHX 28-Lead (3mm 6mm) Plastic QFN 40C to 125C Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25C. A PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Input Voltage l 2.9 3.4 V V Quiescent Current V = 0V, V = 0V 1.0 5 A IN EN/UV SYNC l 1.0 20 A V = 2V, Not Switching, V = 0V 1.7 6 A EN/UV SYNC l 1.7 20 A V = 2V, Not Switching, V = 2V 0.3 2.0 mA EN/UV SYNC l V Current in Regulation V = 0.97V, V = 6V, Output Load = 100A 24 60 A IN OUT IN l V = 0.97V, V = 6V, Output Load = 1mA 230 370 A OUT IN Feedback Reference Voltage V = 12V, I = 500mA 0.964 0.970 0.976 V IN LOAD V = 12V, I = 500mA l 0.958 0.970 0.982 V IN LOAD l Feedback Voltage Line Regulation V = 4.0V to 25V, I = 0.5A 0.004 0.025 %/V IN LOAD Feedback Pin Input Current V = 1V 20 0.5 20 nA FB BIAS Pin Current Consumption V = 3.3V, I = 2A, 2MHz 14 mA BIAS LOAD Rev. A 2 For more information www.analog.com GND ICTRL GND IMON GND ISN GND ISP