POWER LOSS (W) LTC3612 3A, 4MHz Monolithic Synchronous Step-Down DC/DC Converter FEATURES DESCRIPTION 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 n High Efficiency: Up to 95% zero current in shutdown. The 2.25V to 5.5V input sup- n Low Dropout Operation: 100% Duty Cycle ply voltage range makes the LTC3612 ideally suited for n Shutdown Current: 1A single Li-Ion as well as fixed low voltage input applica- n Adjustable Switching Frequency: Up to 4MHz tions. 100% duty cycle capability provides low dropout n Optional Active Voltage Positioning (AVP) with operation, extending the operating time in battery-pow- Internal Compensation ered systems. n Selectable Pulse-Skipping/Forced Continuous/ The operating frequency is externally programmable up to Burst Mode Operation with Adjustable Burst Clamp 4MHz, allowing the use of small surface mount inductors. n Programmable Soft-Start For switching noise-sensitive applications, the LTC3612 n Inputs for Start-Up Tracking or External Reference can be synchronized to an external clock at up to 4MHz. n DDR Memory Mode, I = 1.5A OUT n Forced continuous mode operation in the LTC3612 Available in Thermally Enhanced 20-Pin reduces noise and RF interference. Adjustable compen- (3mm 4mm) QFN and TSSOP Packages n sation allows the transient response to be optimized over AEC-Q100 Qualified for Automotive Applications a wide range of loads and output capacitors. APPLICATIONS The internal synchronous switch increases efficiency and eliminates the need for an external catch diode, saving n Point-of-Load Supplies external components and board space. The LTC3612 is n Distributed Power Supplies offered in a leadless 20-pin 3mm 4mm QFN or a ther- n Portable Computer Systems mally enhanced 20-pin TSSOP package. n DDR Memory Termination All registered trademarks and trademarks are the property of their respective owners. Protected n Handheld Devices by U.S. patents, including 6580258, 5481178, 5994885, 6304066, 6498466, 6611131. TYPICAL APPLICATION Efficiency and Power Loss vs Load Current 100 10 V 90 IN 2.5V TO 5.5V 22F 80 1 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 Rev. D 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC3612 ABSOLUTE MAXIMUM RATINGS (Note 1) 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) .......................................... 55C to 150C 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 PIN CONFIGURATION TOP VIEW TOP VIEW SV 1 20 PV IN IN DRV RUN 2 19 SW 20 19 18 17 PGOOD 3 18 NC DDR 1 16 PGOOD MODE 4 17 SW RUN RT/SYNC 2 15 V 5 16 PV FB IN 21 SGND 3 14 SV IN 21 ITH 6 15 PV IN NC 4 13 PV IN DRV TRACK/SS 7 14 SW SW 5 12 SW DDR 8 13 NC SW 6 11 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 4mm) PLASTIC QFN T = 150C, = 38C/W JMAX JA T = 150C, = 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 ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3612EUDC PBF LTC3612EUDC TRPBF LDQT 20-Lead (3mm 4mm) Plastic QFN 40C to 125C LTC3612IUDC PBF LTC3612IUDC TRPBF LDQT 20-Lead (3mm 4mm) Plastic QFN 40C to 125C LTC3612HUDC PBF LTC3612HUDC TRPBF LDQT 20-Lead (3mm 4mm) Plastic QFN 40C to 150C LTC3612MPUDC PBF LTC3612MPUDC TRPBF LDQT 20-Lead (3mm 4mm) Plastic QFN 55C to 150C LTC3612EFE PBF LTC3612EFE TRPBF LTC3612FE 20-Lead Plastic TSSOP 40C to 125C LTC3612IFE PBF LTC3612IFE TRPBF LTC3612FE 20-Lead Plastic TSSOP 40C to 125C LTC3612HFE PBF LTC3612HFE TRPBF LTC3612FE 20-Lead Plastic TSSOP 40C to 150C LTC3612MPFE PBF LTC3612MPFE TRPBF LTC3612FE 20-Lead Plastic TSSOP 55C to 150C Rev. D 2 For more information www.analog.com NC TRACK/SS PV ITH IN V PV IN FB NC MODE