POWER LOSS (W) LTC3876 Dual DC/DC Controller for DDR Power with Differential VDDQ Sensing and 50mA VTT Reference FEATURES DESCRIPTION n Complete DDR Power Solution with VTT Reference The LTC 3876 is a complete DDR power solution, com- n Wide V Range: 4.5V to 38V, VDDQ: 1V to 2.5V patible with DDR1, DDR2, DDR3 and future DDRX lower IN n 0.67% VDDQ Output Voltage Accuracy voltage standards. The LTC3876 includes VDDQ and VTT n VDDQ and VTT Termination Controllers DC/DC controllers and a precision linear VTT reference. A n 1.2% 50mA Linear VTTR Reference Output differential output sense amplifier and precision internal n Controlled On-Time, Valley Current Mode Control reference combine to offer an accurate VDDQ supply. The n Frequency Programmable from 200kHz to 2MHz VTT controller tracks the precision VTTR linear reference Synchronizable to External Clock with less than 20mV total DC error. The precision VTTR n t = 30ns, t = 90ns reference maintains 1.2% regulation accuracy tracking one- ON(MIN) OFF(MIN) n R or Inductor DCR Current Sensing half VDDQ over temperature for a 50mA reference load. SENSE n Power Good Output Voltage Monitor The LTC3876 allows operation from 4.5V to 38V maximum n Overvoltage Protection and Current Limit Foldback at the input. The VDDQ output can range from 1.0V to n Thermally Enhanced 38-Pin (5mm 7mm) QFN and 2.5V, with a corresponding VTT and VTTR output range TSSOP Packages of 0.5V to 1.25V. Voltage tracking soft-start, PGOOD and fault protection features are provided. APPLICATIONS L, LT, LTC, LTM, Linear Technology, OPTI-LOOP, and the Linear logo are registered trademarks and Hot Swap and No R are trademarks of Linear Technology Corporation. All other SENSE n trademarks are the property of their respective owners. Protected by U.S. Patents including Motherboard Memory 5481178, 5487554, 6580258, 6304066, 6476589, 6774611. n Servers TYPICAL APPLICATION DDR3 1.5V VDDQ/20A 0.75VTT/10A 4.5V to 14V Input V IN 4.5V TO V Efficiency/Power Loss IN LTC3876 14V SENSE1 SENSE2 VDDR Channel 1 C 0.1F IN1 0.1F + + SENSE1 SENSE2 100 4.5 180F 15k 15k 0.1F V = 12V 0.1F IN w 2 VDDQ = 1.5V 4.0 BOOST1 BOOST2 3.57k 90 3.57k 3.5 L1 L2 MT2 MT1 TG1 TG2 0.47H 0.47H VTT 1.5V, 20A DISCONTINUOUS 80 3.0 SW1 SW2 0.75V VDDQ MODE DB1 DB2 10A 2.5 DRV DRV 70 CC1 CC2 C OUT2 2.0 330F INTV CC 1F 4.7F w 2 60 1.5 C OUT1 30.1k MB1 BG1 BG2 MB2 100F 1.0 50 FORCED PGND 0.5 CONTINUOUS 20k + V MODE OUTSENSE1 1F 40 0 VTTRVCC 0.1 110 V OUTSENSE1 100k VTTSNS LOAD CURRENT (A) PGOOD PGOOD VTTR 3876 TA01b 0.1F VTTR 50mA TRACK/SS1 2.2F 15k 1000pF 1000pF ITH1 15k ITH2 100k RT SGND RUN 3876 TA01a 3876f 1 C OUT4 330F C OUT3 100F EFFICIENCY (%)LTC3876 ABSOLUTE MAXIMUM RATINGS (Note 1) TRACK/SS1 Voltage ..................................... 0.3V to 5V Input Supply Voltage (V ) ......................... 0.3V to 40V IN DTR1, CVCC, PHASMD, RT, V , V , VTTSNS, RNG1 RNG2 BOOST1, BOOST2 Voltages ....................... 0.3V to 46V VDDQSNS, VTTR, ITH1, ITH2 SW1, SW2 Voltages ...................................... 5V to 40V Voltages ................................0.3V to (INTV + 0.3V) CC INTV , DRV , DRV , EXTV , PGOOD, RUN, CC CC1 CC2 CC Operating Junction Temperature Range (BOOST1-SW1), (BOOST2-SW2), MODE/PLLIN (Notes 2, 3, 4) ....................................... 40C to 125C Voltages ....................................................... 0.3V to 6V Storage Temperature Range .................. 65C to 150C + + V , V , SENSE1 , SENSE1 , OUTSENSE1 OUTSENSE1 Lead Temperature (Soldering, 10 sec) + SENSE2 , SENSE2 Voltages ....................... 0.6V to 6V FE Package ......................................................300C PIN CONFIGURATION TOP VIEW TOP VIEW CVCC 1 38 V RNG2 2 37 VTTSNS SENSE2 + 3 36 BOOST SENSE2 38 37 36 35 34 33 32 PHASMD 4 35 TG2 ITH2 1 31 TG2 5 SW2 ITH2 34 VDDQSNS 2 30 SW2 6 33 BG2 VDDQSNS VTTR 3 29 BG2 VTTR 7 32 DRV CC VTTRVCC 4 28 DRV CC2 VTTRVCC 8 31 EXTV CC MODE/PLLIN 5 27 EXTV CC 9 30 INTV MODE/PLLIN CC CLKOUT 6 26 INTV CC PGND PGND CLKOUT 10 29 PGND 39 SGND 7 25 PGND 39 SGND 11 28 V IN RT 8 24 V IN 12 27 DRV RT CC1 V 9 23 DRV RNG1 CC1 13 26 BG1 V ITH1 10 22 BG1 RNG1 ITH1 14 25 SW1 TRACK/SS1 11 21 SW1 + 20 15 TG1 V 12 TG1 TRACK/SS1 24 OUTSENSE1 + 13 14 15 16 17 18 19 16 23 BOOST1 V OUTSENSE1 V 17 22 PGOOD OUTSENSE1 + SENSE1 18 21 RUN 19 20 DTR1 SENSE1 UHF PACKAGE 38-LEAD (5mm 7mm) PLASTIC QFN FE PACKAGE T = 125C, = 34C/W 38-LEAD PLASTIC TSSOP JMAX JA EXPOSED PAD (PIN 39) IS PGND, MUST BE SOLDERED TO PCB PGND T = 125C, = 28C/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 LTC3876EUHF PBF LTC3876EUHF TRPBF 3876 40C to 125C 38-Lead (5mm 7mm) Plastic QFN LTC3876IUHF PBF LTC3876IUHF TRPBF 3876 38-Lead (5mm 7mm) Plastic QFN 40C to 125C LTC3876EFE PBF LTC3876EFE TRPBF LTC3876FE 38-Lead Plastic TSSOP 40C to 125C LTC3876IFE PBF LTC3876IFE TRPBF LTC3876FE 38-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: