LT8611 42V, 2.5A Synchronous Step-Down Regulator with Current Sense and 2.5A Quiescent Current FEATURES DESCRIPTION n Rail-to-Rail Current Sense Amplifier with Monitor The LT 8611 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 2.5A of quiescent current. Top and n 2.5A 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 n 96% Efficiency at 1A, 5V from 12V control pins allows accurate input or output current OUT IN n 94% Efficiency at 1A, 3.3V from 12V regulation and limiting. Low ripple Burst Mode operation OUT IN n Fast Minimum Switch-On Time: 50ns enables high efficiency down to very low output currents n Low Dropout Under All Conditions: 200mV at 1A while keeping the output ripple below 10mV . A SYNC P-P n Allows Use of Small Inductors pin allows synchronization to an external clock. Internal n Low EMI compensation with peak current mode topology allows n Adjustable and Synchronizable: 200kHz to 2.2MHz the use of small inductors and results in fast transient n Current Mode Operation response and good loop stability. The EN/UV pin has an n Accurate 1V Enable Pin Threshold accurate 1V threshold and can be used to program V IN n Internal Compensation undervoltage lockout or to shut down the LT8611 reduc- n Output Soft-Start and Tracking ing the input supply current to 1A. A capacitor on the n Small Thermally Enhanced 3mm 5mm 24-Lead TR/SS pin programs the output voltage ramp rate during QFN Package start-up. The PG flag signals when V is within 9% of OUT n AEC-Q100 Qualified for Automotive Applications the programmed output voltage as well as fault conditions. The LT8611 is available in a small 24-lead 3mm 5mm APPLICATIONS QFN package with exposed pad for low thermal resistance. All registered trademarks and trademarks are the property of their respective owners. n Automotive and Industrial Supplies n General Purpose Step-Down n CCCV Power Supplies TYPICAL APPLICATION 12V to 5V Efficiency IN OUT 5V Step-Down Converter with 2.5A Output Current Limit 100 V IN V BST 95 IN 5.5V TO 42V 4.7F 0.1F 90 ON OFF EN/UV 4.7H 0.02 V OUT SYNC 85 SW 5V LT8611 1F 2.5A 80 IMON ISP ICTRL 75 ISN 70 BIAS 10pF 65 PG INTV CC f = 700kHz 60 SW TR/SS V = 12V IN 55 1M 0.1F V = 24V IN RT FB 50 PGND GND 1F 0 0.5 1 1.5 2 2.5 60.4k 243k 47F LOAD CURRENT (A) 8611 TA01a 8611 G01 f = 700kHz SW Rev. B 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT8611 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , EN/UV, PG, ISP, ISN ...........................................42V IN BIAS ..........................................................................30V BST Pin Above SW Pin................................................4V 24 23 22 21 1 FB, TR/SS, RT, INTV , IMON, ICTRL.......................4V SYNC 20 FB CC TR/SS 2 19 PG SYNC Voltage ...........................................................6V RT 3 18 BIAS Operating Junction Temperature Range (Note 2) EN/UV 4 17 INTV CC 25 LT8611E ................................................. 40 to 125C GND V 5 BST 16 IN LT8611I .................................................. 40 to 125C 6 V 15 SW IN Storage Temperature Range ......................65 to 150C 7 PGND 14 SW PGND 8 13 SW 9 10 11 12 UDD PACKAGE 24-LEAD (3mm 5mm) PLASTIC QFN = 40C/W, = 5C/W JA JC(PAD) EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT8611EUDD PBF LT8611EUDD TRPBF LGBR 24-Lead (3mm 5mm) Plastic QFN 40C to 125C LT8611IUDD PBF LT8611IUDD TRPBF LGBR 24-Lead (3mm 5mm) Plastic QFN 40C to 125C AUTOMOTIVE PRODUCTS** LT8611EUDD WPBF LT8611EUDD WTRPBF LGBR 24-Lead (3mm 5mm) Plastic QFN 40C to 125C LT8611IUDD WPBF LT8611IUDD WTRPBF LGBR 24-Lead (3mm 5mm) 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. **Versions of this part are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. These models are designated with a W suffix. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for thesemodels. Rev. B 2 For more information www.analog.com NC ICTRL NC IMON NC ISN NC ISP