POWER LOSS (W) LTC3617 6A Monolithic Synchronous Step-Down Regulator for DDR Termination Features Description n 6A Output Current The LTC 3617 is a high efficiency monolithic synchronous n 2.25V to 5.5V Input Voltage Range buck regulator utilizing a current mode, constant frequency n 10mV Output Voltage Accuracy architecture. It operates from an input voltage range of n Optimized for Low Output Voltages Down to 0.5V 2.25V to 5.5V and provides a regulated output voltage n High Efficiency equal to 0.5 VDDQIN while sourcing and sinking up to n Integrated Buffer for VTTR = VDDQIN 0.5 6A of load current. An internal amplifier provides a VTTR n Shutdown Current: <1A output voltage equal to 0.5 VDDQIN with an output cur- n Adjustable Switching Frequency: Up to 4MHz rent capability of 10mA. n Optional Internal Compensation The operating frequency is externally programmable up to n Internal Soft-Start 4MHz, allowing the use of small surface mount inductors. n Power Good Status Output For switching-noise-sensitive applications, the LTC3617 n Input Overvoltage Protected can be synchronized to an external clock up to 4MHz. n Thermally Enhanced 24-Pin 3mm 5mm Forced continuous mode operation in the LTC3617 reduces QFN Package noise and RF interference. Adjustable external compensa- tion allows the transient response to be optimized over a a wide range of loads and output capacitors. n DDR Termination The internal synchronous switch increases efficiency and n Supports DDR, DDR2 and DDR3 Standards eliminates the need for an external catch diode, minimizing n Tracking Supplies external component count and board space. The LTC3617 is offered in a leadless 24-pin 3mm 5mm thermally enhanced QFN package. L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode 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, 6498466, 6611131. Efficiency and Power Loss t ypical a vs Load Current 100 10 V IN 2.5V 90 22F 4 SV PV 80 IN IN V REF RUN VTTR 1.25V 70 1 VDDQIN 10mA 0.1F 60 RT 0.15H VTT LTC3617 50 SW 1.25V 6A 40 PGOOD SGND 47F 0.1 2 ITH PGND 30 SYNC V FB 20 3617 TA01a 10 0 0.01 0.1 1 10 LOAD CURRENT (A) 3617 TA01b 3617fa 1 EFFICIENCY (%) pplication pplicationsLTC3617 a bsolute Maxi Mu M r p in c F (Note 1) TOP VIEW PV , SV Voltages ..................................... 0.3V to 6V IN IN SW Voltage ................................. 0.3V to (PV + 0.3V) IN ITH, RT, SYNC Voltages .............. 0.3V to (SV + 0.3V) IN 24 23 22 21 VTTR, RUN, V Voltages ........... 0.3V to (SV + 0.3V) FB IN RT 1 20 SYNC VDDQIN, PGOOD Voltages ........................... 0.3V to 6V SGND 2 19 RUN Operating Junction Temperature Range VTTR 3 18 SV IN (Notes 2, 8) ............................................ 40C to 125C PV PV 4 17 IN IN 25 Storage Temperature.............................. 65C to 150C SW 5 16 SW PGND SW 6 15 SW SW 7 14 SW SW 8 13 SW 9 10 11 12 UDD PACKAGE 24-LEAD (3mm 5mm) PLASTIC QFN T = 125C, = 43C/W JMAX JA EXPOSED PAD (PIN 25) IS PGND, MUST BE SOLDERED TO PCB o r Der i n F M LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3617EUDD PBF LTC3617EUDD TRPBF LFXC 40C to 125C 24-Lead (3mm 5mm) Plastic QFN LTC3617IUDD PBF LTC3617IUDD TRPBF LFXC 24-Lead (3mm 5mm) 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 non-standard lead based finish parts. For more information on lead free part marking, go to: