LTC3877 Dual Phase Step-Down Synchronous Controller with VID Output Voltage Programming and Low Value DCR Sensing Fea T Descrip T n 6-Bit Parallel VID (Voltage Identification) Inputs Set The LTC 3877 is a VID-programmable, constant frequency Output Voltage from 0.6V to 1.23V in 10mV Steps current mode step-down controller using an advanced and n proprietary architecture. This new architecture enhances Output Voltage Range: 0.6V to 5V (Without VID) n the signal-to-noise ratio of the current sense signal, al- Ultra Low Value DCR/R Current Sensing SENSE n lowing the use of very low DC resistance power inductors 1% Maximum Total Regulation Voltage Accuracy to maximize efficiency in high current applications. This Over Temperature n feature also dramatically reduces the current sensing error, Dual Differential Remote Sensing Amplifiers so that current sharing is greatly improved in multi-phase n t = 40ns, Capable of Very Low Duty Cycles at ON(MIN) low DCR applications. In addition, the controller achieves a High Frequency minimum on-time of just 40ns, permitting the use of high n Phase-Lockable Frequency from 250kHz to 1MHz switching frequency at high step-down ratios. n Current Mismatch Between Channels: 5% Max n Adjustable Soft-Start Current Ramping or Tracking The LTC3877 features dual high speed remote sense dif- n Multi-IC Operation Up To 12 Phases ferential amplifiers, programmable current sense limits n Wide V Range: 4.5V to 38V and DCR temperature compensation to limit the maximum IN n Dual Power Good Output Voltage Monitors output current precisely over temperature. The LTC3877 n Output Overvoltage Protection also features a precise 0.6V reference with guaranteed n Foldback Output Current Limiting and Soft Recovery accuracy of 0.5%. The LTC3877 is available in a low profile 44-lead 7mm 7mm QFN package. a T L, LT, LTC, LTM, Burst Mode, OPTI-LOOP, PolyPhase, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the n FPGAs and Processor Power property of their respective owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 6304066, 6580258. n Servers and Computing Typical a T Efficiency and Power Loss High Efficiency Dual Phase Single Output, 400kHz, 0.9V/60A Step-Down Converter V IN vs Load Current 6V TO 20V + 10F INTV CC FROM 4 270F V INTV CHL SEL 4.7F IN CC 100 10 34.8k P PINS NOT SHOWN 12V V IN 9 400kHz IN THIS CIRCUIT: RUN VID EN 95 CLKOUT CCM VID 1,2,3,4 8 10k EXTV EFFICIENCY CC I LIM MODE/PLLIN PGOOD1 7 90 PGOOD2 TG1 TG2 6 PHASMD 0.1F 0.1F LTC3877 ITEMP 0.25H 0.25H 5 85 BOOST1 BOOST2 (0.32m DCR) (0.32m DCR) 4 SW1 SW2 POWER LOSS 80 3 BG1 BG2 V = 1.2V OUT 2 GND 75 V = 0.9V OUT 715 715 V = 1.2V 1 OUT + + SNSA1 SNSA2 V = 0.9V OUT 220nF 220nF 70 0 0 10 20 30 40 50 60 SNS1 SNS2 220nF 220nF 3.57k 3.57k LOAD CURRENT (A) + + V OUT SNSD1 SNSD2 3877 TA01b V + 0.9V OUT V FB2 + 60A V V OSNS1 100F FB1 100F 10k 2 V 2 OSNS1 DIFFOUT I TH1 + V + FB2 330F 330F I 20k TH2 FREQ 3 3 1.5nF TK/SS1 TK/SS2 VID 0,5 86.6k 8.45k 0.1F 3877 TA01 3877f 1 For more information www.linear.com/LTC3877 EFFICIENCY (%) ion pplica ions pplica ion uresLTC3877 a Te Maxi Mu M r a T p c F T (Note 1) TOP VIEW Input Supply Voltage (V ) ......................... 0.3V to 40V IN Topside Driver Voltages (BOOST1, BOOST2) ............................... 0.3V to 46V Switch Voltages (SW1, SW2) ........................ 5V to 40V + + + + + SNSA1 1 33 SW1 SNSA1 , SNSD1 , SNS1 , SNSA2 , SNSD2 , TK/SS1 2 32 TG1 SNS2 Voltages ................................0.3V to INTV + CC V 3 31 BOOST1 OSNS1 V 4 30 BG1 OSNS1 (BOOST1-SW1), (BOOST2-SW2) Voltages ... 0.3V to 6V DIFFOUT 5 29 V IN 45 RUN Voltage................................................... 0.3 to 9V V 6 28 INTV FB1 CC SGND/PGND I 7 27 EXTV TH1 CC PGOOD1, PGOOD2, I 8 26 BG2 TH2 EXTV Voltages ..................................... 0.3V to 6V TK/SS2 9 25 BOOST2 CC + V 10 24 TG2 FB2 MODE/PLLIN, FREQ, PHASMD Voltages ... 0.3V to INTV CC V 11 23 SW2 FB2 CHL SEL, VID(s), VID EN Voltages ......0.3V to INTV CC TK/SS1, TK/SS2 Voltages .....................0.3V to INTV CC I , I , ITEMP, I Voltages ............0.3V to INTV TH1 TH2 LIM CC + + V , V , V , V , FB1 OSNS1 OSNS1 FB2 V Voltages ..................................0.3V to INTV FB2 CC UK PACKAGE INTV Peak Output Current ................................100mA CC 44-LEAD (7mm 7mm) PLASTIC QFN Operating Junction Temperature Range T = 125C, = 34C/W, = 3.0C/W JMAX JA JC EXPOSED PAD (PIN 45) IS SGND/PGND, MUST BE SOLDERED TO PCB (Note2, Note 3) .................................. 40C to 125C Storage Temperature Range .................. 65C to 125C o r D i n F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3877EUK PBF LTC3877EUK TRPBF LTC3877UK 44-Lead (7mm 7mm) Plastic QFN 40C to 125C LTC3877IUK PBF LTC3877IUK TRPBF LTC3877UK 40C to 125C 44-Lead (7mm 7mm) Plastic QFN Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on nonstandard lead based finish parts. For more information on lead free part marking, go to: