LTC3811 High Speed Dual, Multiphase Step-Down DC/DC Controller FEATURES DESCRIPTION Fixed Frequency, Peak Current Mode Control The LTC 3811 is a dual, PolyPhase synchronous step- 0.5% Output Accuracy Over Temperature down switching regulator controller optimized for output Optimized for Low V Applications (Up to 3.3V) voltages up to 3.3V. The LTC3811 includes high bandwidth OUT Dual or Single Output, Multiphase Operation error ampli ers as well as a high speed differential remote Wide V Range: 4.5V to 30V Operation sense ampli er. The sense voltage range is programmable IN High Speed Differential Remote Sense Ampli er from 24mV to 85mV, allowing the use of either the inductor Inductor DCR or Sense Resistor Capable DCR or a discrete sense resistor. Multiphase operation is Adjustable Peak Current Sense Voltage: made possible using the MODE/SYNC input, the CLKOUT 24mV to 85mV output and the PHASEMODE control pin, allowing 1-, 2-, Very Low Duty Cycle Operation: t = 65ns (Typ) 3-, 4-, 6- or 12-phase operation. ON(MIN) Powerful Internal Gate Drivers Large internal gate drivers minimize switching losses and Output Voltage Soft-Start, Tracking and Sequencing allow the use of multiple power MOSFETs connected in Programmable Load Line for Reduced C OUT parallel for high current applications. Clock Input and Output for Up to 12-Phase Operation The operating frequency of the LTC3811 can be programmed Fixed Frequency Operation from 250kHz to 750kHz from 250kHz to 750kHz and can also be synchronized to PLL Synchronization from 150kHz Up to 900kHz an external clock using the internal PLL. Selectable CCM or DCM Operation Available in 5mm 7mm QFN and G36 Packages Tracking and sequencing are possible with the LTC3811, and soft-start is programmed with an external capacitor. APPLICATIONS Shutdown reduces supply current to 20A. Network Servers , LT, LTC, LTM and PolyPhase are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. High Current ASIC Supplies Protected by U.S. Patents, including 5481178, 6304066, 5929620, 6177787, 6144194, 6580258, 5705919. Low Voltage Power Distribution TYPICAL APPLICATION Dual Output, 2-Phase Tracking Core and I/O Supply V IN Load Step 4.5V TO 14V V INTV DRV IN CC CC TG1 TG2 V OUT BOOST1 BOOST2 100mV/DIV SW1 SW2 BG1 BG2 RUN1 PGND RUN2 LTC3811 + + SENSE1 SENSE2 I L 5A/DIV SENSE1 SENSE2 + DIFF/IN RNG1 DIFF/IN RNG2 DIFF/OUT V OUT1 2V FB1 FB2 3811 TA01b V OUT2 V = 12V 20s/DIV IN 15A COMP1 COMP2 1.5V V = 2V OUT 15A SS/TRACK1 SGND SS/TRACK2 I = 0A to 12.5A OUT 3811 TA01a 3811f 1LTC3811 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Supply Voltage (V ) ......................... 0.3V to 30V FB1, FB2, RNG1, RNG2, SS/TRACK1, SS/TRACK2, IN + + Topside Driver Voltages PLL/LPF, SENSE1 , SENSE1 , SENSE2 , (BOOST1, BOOST2) ............................... 0.3V to 37V SENSE2 Voltages ................................. 0.3V to INTV CC Switch Voltage (SW1, SW2) ......................... 5V to 30V DRV LDO RMS Output Current .........................100mA CC BOOST1 SW1, BOOST2 SW2 ................. 0.3V to 7V OperatingTemperature Range (Note 2)..... 40C to 85C + , INTV , EXTV , RUN1, RUN2, DIFF/IN , Junction Temperature (Note 3) ............................. 125C DRV CC CC CC DIFF/IN , PHASEMODE, PGOOD1, PGOOD2, Storage Temperature Range ................... 65C to 125C MODE/SYNC Voltages .................................. 0.3V to 7V Lead Temperature (Soldering, 10 sec) SSOP Package ..................................................300C PIN CONFIGURATION TOP VIEW TOP VIEW 1 36 PGOOD2 PGOOD1 RUN1 2 35 PLL/LPF 38 37 36 35 34 33 32 3 MODE/SYNC RUN2 34 + + SENSE1 1 31 BOOST1 4 33 BOOST1 SENSE1 SENSE1 2 30 TG1 SENSE1 5 32 TG1 SS/TRACK1 3 29 SW1 SS/TRACK1 6 31 SW1 COMP1 BG1 4 28 7 30 BG1 COMP1 FB1 5 27 EXTV CC FB1 8 29 EXTV CC SGND 6 26 PGND SGND 9 28 PGND 39 INTV 7 25 DRV CC CC 10 DRV INTV 27 CC CC FB2 8 24 V IN 11 26 V FB2 IN COMP2 9 23 BG2 COMP2 12 25 BG2 SS/TRACK2 10 22 SW2 13 SW2 SS/TRACK2 24 SENSE2 11 21 TG2 + 14 23 TG2 SENSE2 SENSE2 12 20 BOOST2 + SENSE2 15 22 BOOST2 13 14 15 16 17 18 19 DIFF/OUT 16 21 CLKOUT 17 20 RNG2 DIFF/IN + DIFF/IN 18 19 RNG1 UHF PACKAGE 38-LEAD (5mm 7mm) PLASTIC QFN G PACKAGE 36-LEAD PLASTIC SSOP WIDE T = 125C, = 34C/W JMAX JA T = 125C, = 100C/W JMAX JA EXPOSED PAD (PIN 39) IS PGND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3811EUHF PBF LTC3811EUHF TRPBF 3811 38-Lead (5mm 7mm) Plastic QFN 40C to 85C LTC3811EG PBF LTC3811EG TRPBF LTC3811EG 36-Lead Plastic SSOP Wide 40C to 85C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: