POWER LOSS (W) LTC3612 3A, 4MHz Monolithic Synchronous Step-Down DC/DC Converter Fae Tseru Dpircse Tnoi n 3A Output Current The LTC 3612 is a low quiescent current monolithic syn- n 2.25V to 5.5V Input Voltage Range chronous buck regulator using a current mode, constant n Low Output Ripple Burst Mode Operation: I = 70A frequency architecture. The no-load DC supply current Q n 1% Output Voltage Accuracy in sleep mode is only 70A while maintaining the output n Output Voltage Down to 0.6V voltage (Burst Mode operation) at no load, dropping to zero n High Efficiency: Up to 95% current in shutdown. The 2.25V to 5.5V input supply voltage n Low Dropout Operation: 100% Duty Cycle range makes the LTC3612 ideally suited for single Li-Ion n Shutdown Current: 1A as well as fixed low voltage input applications. 100% duty n Adjustable Switching Frequency: Up to 4MHz cycle capability provides low dropout operation, extending n Optional Active Voltage Positioning (AVP) with the operating time in battery-powered systems. Internal Compensation The operating frequency is externally programmable up to n Selectable Pulse-Skipping/Forced Continuous/ 4MHz, allowing the use of small surface mount inductors. Burst Mode Operation with Adjustable Burst Clamp For switching noise-sensitive applications, the LTC3612 n Programmable Soft-Start can be synchronized to an external clock at up to 4MHz. n Inputs for Start-Up Tracking or External Reference n Forced continuous mode operation in the LTC3612 reduces DDR Memory Mode, I = 1.5A OUT n noise and RF interference. Adjustable compensation allows Available in Thermally Enhanced 20-Pin the transient response to be optimized over a wide range (3mm 4mm) QFN and TSSOP Packages of loads and output capacitors. a acilpp Tsnoi The internal synchronous switch increases efficiency and n eliminates the need for an external catch diode, saving Point-of-Load Supplies n external components and board space. The LTC3612 is Distributed Power Supplies n offered in a leadless 20-pin 3mm 4mm QFN or a thermally Portable Computer Systems n enhanced 20-pin TSSOP package. DDR Memory Termination n Handheld Devices L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 6580258, 5481178, 5994885, 6304066, 6498466, 6611131. T lacipy a acilpp Tnoi Efficiency and Power Loss vs Load Current 100 10 V 90 IN 2.5V TO 5.5V 22F 80 1 s 2 SV PV IN IN 70 RUN PV IN DRV 60 0.1 TRACK/SS DDR RT/SYNC 560nH V 50 OUT LTC3612 SW 2.5V 40 0.01 3A PGOOD SGND 47F ITH PGND 30 MODE V FB 20 0.001 665k V = 5V IN 3612 TA01a V = 3.3V 10 IN V = 2.8V IN 210k 0 1 10 100 1000 10000 OUTPUT CURRENT (mA) 3612 TA01b 3612fa EFFICIENCY (%)LTC3612 a ulosb T e Mixa Mu M r a Tsgni (Notes 1, 11) PV , SV , PV Voltages ..................... 0.3V to 6V Operating Junction Temperature Range IN IN IN DRV SW Voltage ..................................0.3V to (PV + 0.3V) (Notes 2, 11) .......................................... 40C to 125C IN ITH, RT/SYNC Voltages ............... 0.3V to (SV + 0.3V) Storage Temperature .............................. 65C to 150C IN DDR, TRACK/SS Voltages ........... 0.3V to (SV + 0.3V) Reflow Peak Body Temperature (QFN) .................. 260C IN MODE, RUN, V Voltages .......... 0.3V to (SV + 0.3V) Lead Temperature (Soldering, 10 sec) FB IN PGOOD Voltage ............................................ 0.3V to 6V TSSOP .............................................................. 300C p ni c no Farugi Tnoi TOP VIEW TOP VIEW SV 1 20 PV IN IN DRV RUN 2 19 SW 20 19 18 17 PGOOD 3 18 NC 1 16 PGOOD DDR MODE 4 17 SW RT/SYNC 2 15 RUN V 5 16 PV FB IN 21 SGND 3 14 SV IN ITH 6 15 PV 21 IN NC 4 13 PV IN DRV TRACK/SS 7 14 SW SW 5 12 SW DDR 8 13 NC 6 11 SW SW RT/SYNC 9 12 SW 7 8 9 10 SGND 10 11 NC FE PACKAGE UDC PACKAGE 20-LEAD PLASTIC TSSOP 20-LEAD (3mm s 4mm) PLASTIC QFN T = 125C, = 38C/W JMAX JA T = 125C, = 43C/W JMAX JA EXPOSED PAD (PIN 21) IS PGND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 21) IS PGND, MUST BE SOLDERED TO PCB ro D re ni Fro Ma Tnoi LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3612EUDC PBF LTC3612EUDC TRPBF LDQT 40C to 125C 20-Lead (3mm 4mm) Plastic QFN LTC3612IUDC PBF LTC3612IUDC TRPBF LDQT 40C to 125C 20-Lead (3mm 4mm) Plastic QFN LTC3612EFE PBF LTC3612EFE TRPBF LTC3612FE 20-Lead Plastic TSSOP 40C to 125C LTC3612IFE PBF LTC3612IFE TRPBF LTC3612FE 20-Lead Plastic TSSOP 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 non-standard lead based finish parts. For more information on lead free part marking, go to: