POWER LOSS (W) LTC3633 Dual Channel 3A, 15V Monolithic Synchronous Step-Down Regulator FEATURES DESCRIPTION n 3.6V to 15V Input Voltage Range The LTC 3633 is a high efficiency, dual-channel monolithic n 3A Output Current per Channel synchronous buck regulator using a controlled on-time, n Up to 95% Efficiency current mode architecture, with phase lockable switching n Low Duty Cycle Operation: 5% at 2.25MHz frequency. The two channels can run 180 out of phase, n Selectable 0/180 Phase Shift Between Channels which relaxes the requirements for input and output ca- n Adjustable Switching Frequency: 500kHz to 4MHz pacitance. The operating supply voltage range is from 3.6V n External Frequency Synchronization to 15V, making it suitable for dual cell lithium-ion batteries n Current Mode Operation for Excellent Line and as well as point of load power supply applications from Load Transient Response a 12V or 5V supply. n 0.6V Reference Allows Low Output Voltages The operating frequency is programmable and synchroniz- n User Selectable Burst Mode Operation or Forced able from 500kHz to 4MHz with an external resistor. The Continuous Operation high frequency capability allows the use of small surface n Output Voltage Tracking and Soft-Start Capability mount inductors and capacitors. The unique constant n Short-Circuit Protected frequency/controlled on-time architecture is ideal for high n Overvoltage Input and Overtemperature Protection step-down ratio applications that operate at high frequency n Low Power 2.5V Linear Regulator Output while demanding fast transient response. An internal phase n Power Good Status Outputs lock loop servos the on-time of the internal one-shot timer n Available in (4mm 5mm) QFN-28 and 28-Lead to match the frequency of the internal clock or an applied TSSOP Packages external clock. The LTC3633 can select between forced continuous mode APPLICATIONS and high efficiency Burst Mode operation. n Distributed Power Systems 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 n Battery Powered Instruments owners. Protected by U.S. Patents including 5481178, 5847554, 6580258, 6304066, 6476589, n 6774611. Point of Load Power Supplies TYPICAL APPLICATION V IN Efficiency vs Load Current 12V 100 100 47F V V IN2 IN1 RUN1 INTV Burst Mode x2 CC 90 OPERATION RUN2 ITH1 2.2F ITH2 80 10 LTC3633 RT 70 MODE/SYNC 60 1 PHMODE 50 V2P5 TRACKSS2 TRACKSS1 40 0.1 PGOOD2 PGOOD1 30 BOOST2 BOOST1 20 0.01 0.1F 0.1F 1.5H 1H V V V = 5V OUT2 OUT1 OUT 10 SW2 SW1 5V AT 3A 3.3V AT 3A V = 12V V = 3.3V IN OUT V V 0 0.001 ON2 ON1 1 10 100 1000 10000 V V FB2 FB1 LOAD CURRENT (mA) SGND PGND 73.2k 45.3k 3633 TA01b 10k 10k 22F 22F 3633 TA01a 3633fd 1 For more information www.linear.com/LTC3633 EFFICIENCY (%)LTC3633 ABSOLUTE MAXIMUM RATINGS (Note 1) V , V ................................................... 0.3V to 16V V , V , PHMODE.................0.3V to INTV + 0.3V IN1 IN2 FB1 FB2 CC V , V Transient ...................................................18V RUN1, RUN2 .................................... 0.3V to V + 0.3V IN1 IN2 IN PGOOD1, PGOOD2, V , V .................. 0.3V to 16V Operating Junction Temperature Range ON1 ON2 BOOST1, BOOST2 ....................................0.3V to 19.6V (Notes 2, 3) ............................................ 40C to 125C BOOST1-SW1, BOOST2-SW2 .................... 0.3V to 3.6V Storage Temperature Range .................. 65C to 125C V2P5, INTV , TRACKSS1, TRACKSS2 ...... 0.3V to 3.6V CC ITH1, ITH2, RT, MODE/SYNC ........0.3V to INTV + 0.3V CC PIN CONFIGURATION TOP VIEW TOP VIEW ITH1 1 28 V ON1 TRACKSS1 2 27 SW1 V 3 26 SW1 FB1 28 27 26 25 24 23 PGOOD1 4 25 V IN1 PGOOD1 1 22 V IN1 PHMODE 5 24 V PHMODE 2 21 IN1 V IN1 RUN1 6 23 BOOST1 RUN1 3 20 BOOST1 MODE/SYNC 4 19 INTV MODE/SYNC 7 22 INTV CC 29 CC 29 PGND PGND RT 5 18 V2P5 RT 8 21 V2P5 RUN2 6 17 BOOST2 RUN2 9 20 BOOST2 SGND 7 16 V IN2 SGND 10 19 V IN2 8 PGOOD2 15 V IN2 PGOOD2 11 18 V IN2 9 10 11 12 13 14 V 12 17 SW2 FB2 TRACKSS2 13 16 SW2 ITH2 14 15 V ON2 UFD PACKAGE FE PACKAGE 28-LEAD (4mm 5mm) PLASTIC QFN 28-LEAD PLASTIC TSSOP T = 125C, = 43C/W JMAX JA T = 125C, = 25C/W JMAX JA EXPOSED PAD (PIN 29) IS PGND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 29) IS PGND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3633EUFD PBF LTC3633EUFD TRPBF 3633 28-Lead (4mm 5mm) Plastic QFN 40C to 125C LTC3633IUFD PBF LTC3633IUFD TRPBF 3633 40C to 125C 28-Lead (4mm 5mm) Plastic QFN LTC3633EFE PBF LTC3633EFE TRPBF LTC3633FE 28-Lead Plastic TSSOP 40C to 125C LTC3633IFE PBF LTC3633IFE TRPBF LTC3633FE 28-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: