LT3840 Wide Input Range Synchronous Regulator Controller with Accurate Current Limit Fea T Descrip T n Wide Input Range: 2.5V to 60V The LT 3840 is a high voltage synchronous step-down n Integrated Buck-Boost Supply for 7.5V MOSFET switching regulator controller capable of operating from Gate Drive a 2.5V to 60V supply. n Programmable Constant-Current Operation with The LT3840s low quiescent current, when configured for Current Monitor Output user selectable Burst Mode operation, helps extend run n Low I : 75A, 12V to 3.3V Q IN OUT time in battery-powered systems by increasing efficiency n Selectable Low Output Ripple Burst Mode at light loads. The LT3840 uses a constant frequency, Operation current mode architecture. High current applications are n V Up to 60V OUT possible with large N-channel gate drivers capable of n Adjustable and Synchronizable: 50kHz to 1MHz driving multiple low R MOSFETs. DS(ON) n Internal OVLO Protects for Input Transients Up to 80V n Accurate Input Overvoltage and Undervoltage Threshold An integrated buck-boost switching regulator generates n Programmable Soft-Start with Voltage Tracking a 7.5V bias supply voltage for MOSFET gate drive and IC n Power Good and Output OVP power allowing higher efficiency operation over the entire n 28-Lead TSSOP and 38-Lead 4mm 6mm QFN Packages input voltage range and eliminating the need for an external bias voltage. An accurate current limit set point regulates a T the maximum output current. A current monitor reports the average output current. n Automotive Supplies L, LT, LTC, LTM, Linear Technology, Burst Mode, and the Linear logo are registered n Industrial Systems trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Distributed DC Power Systems Typical a T High Efficiency Synchronous Step-Down Converter 12V to 3.3V Efficiency IN OUT V IN 4V TO 60V 1F 68F 33H 100 2 95 90 AUXBST AUXSW1 AUXSW2 EN INTV CC 85 4.7F V 80 IN 75 AUXVIN BOOST LT3840 70 UVLO 1F 65 OVLO TG 1.5H 2m 60 V OUT PG SW 3.3V 55 20A SYNC BG 50 330F 0 5 10 15 20 2 MODE LOAD CURRENT (A) 3840 TA01b + RT SENSE V SENSE C 16.9k 49.9k 20k TK/SS FB 1500pF 10k 100pF GND IMON ICOMP ICTRL 2200pF 7.68k 3840 TA01a 470pF 3840fa For more information www.linear.com/LT3840 1 EFFICIENCY (%) ion pplica ions pplica ion uresLT3840 a Te Maxi Mu M r a T (Note 1) Junction Temperature Range AUXVIN, V , EN and UVLO ....................... 0.3V to 80V IN LT3840E (Note 2) .............................. 40C to 125C PG .............................................................. 0.3V to 25V LT3840I ............................................. 40C to 125C MODE ........................................................... 0.3V to 9V LT3840H ............................................ 40C to 150C + SENSE and SENSE .................................. 0.3V to 60V LT3840MP ......................................... 55C to 150C + SENSE to SENSE ...........................................1V to 1V Lead Temperature (Soldering, 10 sec) OVLO, V , FB, SYNC, TK/SS and ICTRL ....... 0.3V to 6V C TSSOP Only ..........................................................300C Storage Temperature............................. 65C to 150C p c F T TOP VIEW TOP VIEW 1 AUXBST AUXSW1 28 38 37 36 35 34 33 32 2 27 AUXSW2 PGND AUXVIN 1 31 NC AUXVIN 3 26 INTV CC NC 2 30 INTV CC SYNC 4 25 BG SYNC 3 29 BG 5 24 BGRTN RT RT 4 28 BGRTN TK/SS 6 23 BOOST NC 5 27 NC FB 7 29 22 TG TK/SS 6 26 BOOST 39 GND 8 21 SW V C GND FB 7 25 TG 9 20 SENSE PG V 8 24 SW C + MODE 10 19 SENSE PG 9 23 NC 11 ICOMP OVLO 18 NC 10 22 SENSE 12 17 ICTRL + UVLO 21 MODE 11 SENSE EN 13 16 IMON 20 OVLO 12 ICOMP V 14 15 GND IN 13 14 15 16 17 18 19 FE PACKAGE 28-LEAD PLASTIC TSSOP UFE PACKAGE = 30C/W, = 10C/W JA JC 38-LEAD (4mm 6mm) PLASTIC QFN EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB = 38C/W, = 4C/W JA JC EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB o r D i n F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3840EFE PBF LT3840EFE TRPBF LT3840FE 28-Lead Plastic TSSOP 40C to 125C LT3840IFE PBF LT3840IFE TRPBF LT3840FE 28-Lead Plastic TSSOP 40C to 125C LT3840HFE PBF LT3840HFE TRPBF LT3840FE 28-Lead Plastic TSSOP 40C to 150C LT3840MPFE PBF LT3840MPFE TRPBF LT3840FE 28-Lead Plastic TSSOP 55C to 150C LT3840EUFE PBF LT3840EUFE TRPBF 3840 38-Lead (4mm 6mm) Plastic QFN 40C to 125C LT3840IUFE PBF LT3840IUFE TRPBF 3840 38-Lead (4mm 6mm) Plastic QFN 40C to 125C 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 nonstandard lead based finish parts. For more information on lead free part marking, go to: