LTC3649 60V, 4A Synchronous Step-Down Regulator with Rail-to-Rail Programmable Output FEATURES DESCRIPTION n Wide V Range: 3.1V to 60V The LTC 3649 is a high efficiency 60V, 4A synchronous IN n Wide V Range: 0V to (V 0.5V) monolithic step-down regulator. The regulator features OUT IN n Single Resistor V Programming a single resistor programmable output voltage, internal OUT n Integrated 110m Top N-Channel/50m Bottom compensation and high efficiencies over a wide V range. OUT N-Channel MOSFETs The step-down regulator operates from an input voltage n 95% Efficiency with 12V and 5V IN OUT range of 3.1V to 60V and provides an adjustable rail-to-rail n Regulated I : 440A, Shutdown I : 18A Q Q output range from (V 0.5V) to ground while delivering IN n Accurate Current Monitoring (4%) without Sense up to 4A of output current. The switching frequency is Resistor also adjusted with an external resistor. A user-selectable n Accurate Resistor Programmable Frequency mode input is provided to allow the user to trade off ripple (300kHz to 3MHz) with 50% Frequency Sync Range noise for efficiency at light loads Burst Mode operation n Accurate Programmable Output Current provides the highest efficiency at light loads, while forced n Input Voltage Regulation for MPPT Applications continuous mode provides low output ripple. The MODE/ n 0.8% Output Voltage Accuracy SYNC pin can also be used to allow the user to synchronize n Peak Current Mode Operation the switching frequency to an external clock. n Programmable Wire Drop Compensation n The LTC3649 operates with a peak current mode architec- Burst Mode Operation, Forced Continuous Mode n ture that allows for fast transient response with inherent Internal Compensation and Programmable Soft-Start n cycle-to-cycle current limit protection. It also features Overtemperature Protection n programmable output current limit, current monitoring Available in Thermally Enhanced 28-Lead (4mm and input voltage regulation. 5mm) QFN and TSSOP Packages L, LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode and OPTI-LOOP are registered trademarks of Analog Devices, Inc. All other trademarks are the property of their APPLICATIONS respective owners. Protected by U.S. Patents, including 5481178, 5705919, 5847554, 6580258. n Industrial Applications n Automotive Applications TYPICAL APPLICATION Efficiency with V = 5V OUT 100 24V to 5V Burst Mode Operation OUT V = 12V IN 0.1F 98 V = 24V IN 96 6.8H 94 V IN V BOOST SW IN 5.5V TO 60V V OUT 92 RUN V 5V OUT 47F 4A 90 22F LTC3649 2 EXTV CC 88 ITH MODE/SYNC V SGND 86 INREG INTV PGND CC 84 2.2F R ISET T IMON 82 80 10nF 10nF 100k 200k 10k 0 0.5 1 1.5 2 2.5 3 3.5 4 I (A) OUT 3649 TA01b f = 500kHz 3649 TA01a SW 3649fb 1 For more information www.linear.com/LTC3649 EFFICIENCY (%)LTC3649 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) V Voltage (Note 3) .................................. 64V to 0.3V IMON, PGOOD Voltage ................................. 4V to 0.3V IN ISET, OUT Voltage ..................................... 64V to 0.3V V , ITH Voltage ..................................... 4V to 0.3V INREG RUN Voltage............................................... 64V to 0.3V Operating Junction MODE/SYNC Voltage .................................. 6V to 0.3V Temperature Range (Notes 5, 7) ............ 40C to 125C PGDFB, R INTV +0.3V to 0.3V Storage Temperature Range .................. 65C to 125C T ........................................... CC EXTV Voltage ......................................... 28V to 0.3V CC PIN CONFIGURATION TOP VIEW TOP VIEW 1 SW PGND 28 2 SW PGND 27 3 SW PGND 26 28 27 26 25 24 23 4 SW PGND 25 PGND 1 22 SW 5 SW PGND 24 PGND 2 21 SW 6 SW V 3 20 SW V 23 IN IN V 4 19 SW 7 SW 29 V 22 IN IN 29 SGND SGND RUN 5 18 BOOST 8 BOOST RUN 21 SGND 6 17 INTV CC 9 INTV SGND 20 CC MODE/SYNC 7 16 EXTV CC 10 EXTV MODE/SYNC 19 CC PGOOD 8 15 ITH 11 ITH PGOOD 18 9 10 11 12 13 14 12 ISET PGDFB 17 13 V IMON 16 OUT 14 R V 15 T INREG UFD PACKAGE 28-LEAD (4mm 5mm) PLASTIC QFN FE PACKAGE T = 125C, = 43C/W, = 3.4C/W JMAX JA JC 28-LEAD PLASTIC TSSOP EXPOSED PAD (PIN 29) IS SGND, MUST BE SOLDERED TO PCB T = 125C, = 30C/W, = 5C to 10C/W JMAX JA JC EXPOSED PAD (PIN 29) IS SGND, MUST BE SOLDERED TO PCB