LTC3864 60V Low I Step-Down Q DC/DC Controller with 100% Duty Cycle Capability Descrip T Fea T n Wide Operating V Range: 3.5V to 60V The LTC 3864 is a robust, high voltage step-down DC/DC IN n Wide V Range: 0.8V to V OUT IN controller optimized for automotive and industrial applica- n Low Operating I = 40A Q tions. It drives a P-channel power MOSFET switch allowing n Very Low Dropout Operation: 100% Duty Cycle 100% duty cycle operation. The wide input and output volt- n Strong High Voltage MOSFET Gate Driver age ranges cover a multitude of applications. This device n Constant Frequency Current Mode Architecture has been verified with the failure mode and effects analysis n Verified FMEA for Adjacent Pin Open/Short (FMEA) procedure for operation during failure conditions. n Selectable High Efficiency Burst Mode Operation or The LTC3864 offers excellent light load efficiency, draw- Pulse-Skipping Mode at Light Loads ing only 40A quiescent current in a user programmable n Programmable Fixed Frequency: 50kHz to 850kHz n Burst Mode operation. Its peak current mode, constant Phase-Lockable Frequency: 75kHz to 750kHz n frequency PWM architecture provides for good control of Accurate Current Limit n switching frequency and output current limit. The switch- Programmable Soft-Start or Voltage Tracking n ing frequency can be programmed from 50kHz to 850kHz Internal Soft-Start Guarantees Smooth Start-Up n with an external resistor and can be synchronized to an Power Good Output Voltage Monitor n external clock from 75kHz to 750kHz. Low Shutdown I = 7A Q n Available in Small 12-Pin Thermally Enhanced MSOP The LTC3864 offers programmable soft-start or output and DFN Packages tracking. Safety features include overvoltage protection, overcurrent and short-circuit protection including fre- a T quency foldback and a power good output signal. n The LTC3864 is available in thermally enhanced 12-Pin Industrial and Automotive Power Supplies n MSOP and 3mm 4mm DFN packages. Telecom Power Supplies n L, LT, LTC, LTM, OPTI-LOOP, Linear Technology, Burst Mode and the Linear logo are registered Distributed Power Systems trademarks and Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5731694. Typical a T 5.2V to 60V Input, 5V/2A Output, 350kHz Step-Down Converter Efficiency V * IN 100 5.2V TO 60V 0.47F 10F Burst Mode OPERATION 90 CAP RUN V IN 350kHz 25m PLLIN/MODE 80 SENSE SS PULSE-SKIPPING LTC3864 3.3nF GATE 9.09k 70 10H V * OUT ITH 5V 2A 60 FREQ 100k 422k 47F V = 12V IN 2 SGND V = 5V OUT PGOOD 50 0.01 0.1 1 V FB LOAD CURRENT (A) PGND *V FOLLOWS V 80.6k 3864 TA01b OUT IN WHEN 3.5V V 5.2V IN 3864 TA01a 3864fa 1 For more information www.linear.com/LTC3864 EFFICIENCY (%) ion pplica ions pplica ures ionLTC3864 a Te Maxi Mu M r a T (Note 1) Operating Junction Temperature Range (Notes 2, 3, 4) Input Supply Voltage (V ) ......................... 0.3V to 65V IN LTC3864E,I ....................................... 40C to 125C V -V Voltage ...................................... 0.3V to 6V IN SENSE LTC3864H .......................................... 40C to 150C V -V Voltage ........................................ 0.3V to 10V IN CAP LTC3864MP ....................................... 55C to 150C RUN Voltage............................................... 0.3V to 65V Storage Temperature Range .................. 65C to 150C PGOOD, PLLIN/MODE Voltages ................... 0.3V to 6V Lead Temperature (Soldering, 10 sec) SS, ITH, FREQ, V Voltages ........................ 0.3V to 5V FB MSOP Package .................................................300C p in c F T TOP VIEW TOP VIEW PLLIN/MODE 1 12 GATE PLLIN/MODE 1 12 GATE FREQ 2 11 V IN FREQ 2 11 V IN SGND 3 10 SENSE 3 13 SGND 13 10 SENSE PGND 4 PGND SS 9 CAP SS 4 9 CAP V 5 8 RUN FB V 5 8 RUN FB ITH 6 7 PGOOD ITH 6 7 PGOOD MSE PACKAGE 12-LEAD PLASTIC MSOP DE PACKAGE T = 150C, = 40C/W, = 10C/W JMAX JA JC 12-LEAD (4mm 3mm) PLASTIC DFN EXPOSED PAD (PIN 13) IS PGND, MUST BE SOLDERED TO PCB FOR OPTIMAL T = 150C, = 43C/W, = 5.5C/W JMAX JA JC THERMAL PERFORMANCE EXPOSED PAD (PIN 13) IS PGND, MUST BE SOLDERED TO PCB FOR OPTIMAL THERMAL PERFORMANCE o r Der i n F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3864EMSE PBF LTC3864EMSE TRPBF 3864 12-Lead Plastic MSOP 40C to 125C LTC3864IMSE PBF LTC3864IMSE TRPBF 3864 12-Lead Plastic MSOP 40C to 125C LTC3864HMSE PBF LTC3864HMSE TRPBF 3864 12-Lead Plastic MSOP 40C to 150C LTC3864MPMSE PBF LTC3864MPMSE TRPBF 3864 12-Lead Plastic MSOP 55C to 150C LTC3864EDE PBF LTC3864EDE TRPBF 3864 12-Lead (4mm 3mm) Plastic DFN 40C to 125C LTC3864IDE PBF LTC3864IDE TRPBF 3864 12-Lead (4mm 3mm) Plastic DFN 40C to 125C LTC3864HDE PBF LTC3864HDE TRPBF 3864 12-Lead (4mm 3mm) Plastic DFN 40C to 150C LTC3864MPDE PBF LTC3864MPDE TRPBF 3864 12-Lead (4mm 3mm) Plastic DFN 55C to 150C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: