POWER LOSS (mW) LTC3786 Low I Synchronous Q Boost Controller FEATURES DESCRIPTION n Synchronous Operation For Highest Efficiency and The LTC 3786 is a high performance synchronous boost Reduced Heat Dissipation converter controller that drives all N-channel power n Wide V Range: 4.5V to 38V (40V Abs Max) and MOSFETs. Synchronous rectification increases efficiency, IN Operates Down to 2.5V After Start-Up reduces power losses and eases thermal requirements, n Output Voltages Up to 60V allowing the LTC3786 to be used in high power boost n 1% 1.2V Reference Voltage applications. n R or Inductor DCR Current Sensing SENSE A 4.5V to 38V input supply range encompasses a wide n 100% Duty Cycle Capability for Synchronous MOSFET range of system architectures and battery chemistries. n Low Quiescent Current: 55A When biased from the output of the boost converter or n Phase-Lockable Frequency (75kHz to 850kHz) another auxiliary supply, the LTC3786 can operate from n Programmable Fixed Frequency (50kHz to 900kHz) an input supply as low as 2.5V after start-up. The 55A n Adjustable Output Voltage Soft-Start no-load quiescent current extends operating run time in n Power Good Output Voltage Monitor battery-powered systems. n Low Shutdown Current I : <8A Q n The operating frequency can be set for a 50kHz to 900kHz Internal 5.4V LDO for Gate Drive Supply n range or synchronized to an external clock using the Thermally Enhanced 16-Pin 3mm 3mm QFN and internal PLL. The LTC3786 also features a precision 1.2V MSOP Packages reference and a power good output indicator. The SS pin APPLICATIONS ramps the output voltage during start-up. The PLLIN/MODE pin selects among Burst Mode operation, pulse-skipping n Industrial and Automotive Power Supplies mode or continuous inductor current mode at light loads. n Automotive Start-Stop Systems All registered trademarks and trademarks are the property of their respective owners. n Medical Devices n High Voltage Battery-Powered Systems TYPICAL APPLICATION 12V to 24V/5A Synchronous Boost Converter Efficiency and Power Loss V 4.5V TO 24V vs Load Current IN VBIAS 100 10000 + SENSE 90 LTC3786 4m 220F BURST 80 1000 EFFICIENCY SENSE BURST PGOOD 70 LOSS PLLIN/MODE 3.3H RUN 60 100 FREQ TG 50 0.1F V OUT 40 10 SS SW 24V 15nF 0.1F 5A 220F 8.66k 30 ITH BOOST V = 12V 220pF IN 20 1 BG V = 24V OUT 10 Burst Mode OPERATION 12.1k FIGURE 8 CIRCUIT INTV VFB CC 0 0.1 4.7F 0.00001 0.0001 0.001 0.01 0.1 1 10 GND 232k OUTPUT CURRENT (A) 3786 TA01a 3786 TA01b 3786fc 1 For more information www.linear.com/LTC3786 EFFICIENCY (%)LTC3786 ABSOLUTE MAXIMUM RATINGS (Notes 1, 3) + VBIAS ........................................................ 0.3V to 40V SENSE , SENSE ........................................ 0.3V to 40V + BOOST ........................................................0.3V to 71V SENSE SENSE ..................................... 0.3V to 0.3V SW ............................................................. 0.3V to 65V SS, ITH, FREQ, VFB...............................0.3V to INTV CC RUN ............................................................. 0.3V to 8V Operating Junction Temperature Range (Notes 2, 3) Maximum Current Sourced into Pin LTC3786E, LTC3786I ..........................40C to 125C from Source >8V ..............................................100A LTC3786H ...........................................40C to 150C PGOOD, PLLIN/MODE .................................. 0.3V to 6V Storage Temperature Range ....................65C to 150C INTV , (BOOST SW) ............................... 0.3V to 6V Lead Temperature (Soldering, 10 sec) CC MSE Package Only ............................................300C PIN CONFIGURATION TOP VIEW TOP VIEW 16 15 14 13 1 16 PGOOD VFB + SW 1 12 BG SENSE 2 15 SW SENSE 3 14 TG PGOOD 2 11 GND 17 ITH 4 17 13 BOOST GND VFB 3 10 RUN SS 5 GND 12 VBIAS 6 PLLIN/MODE 11 INTV + CC SENSE 4 9 FREQ FREQ 7 10 BG RUN 8 9 GND 5 6 7 8 MSE PACKAGE 16-LEAD PLASTIC MSOP T = 150C, = 40C/W, = 10C/W JMAX JA JC UD PACKAGE EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB 16-LEAD (3mm 3mm) PLASTIC QFN T = 150C, = 68C/W, = 4.2C/W JMAX JA JC EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION