LTC3733/LTC3733-1 3-Phase, Buck Controllers for AMD CPUs FEATURES DESCRIPTIO n 3-Phase Controller with Onboard MOSFET Drivers The LTC 3733 family are PolyPhase synchronous step- n Current Mode Control Ensures Current Sharing down switching regulator controllers that drive all n Differential Amplifier Accurately Senses V N-channel external power MOSFET stages in a phase- OUT n 5% Output Current Matching Optimizes Thermal lockable, fixed frequency architecture. The 3-phase con- Performance and Size of Inductors and MOSFETs troller drives its output stages with 120 phase separation n Reduced Input and Output Capacitance at frequencies of up to 530kHz per phase to minimize the n Supports Active Voltage Positioning RMS current dissipated by the ESR of both the input and n VID Programmable Output Voltage from 0.8V to 1.55V output filter capacitors. The 3-phase technique effectively TM (AMD Opteron CPU) triples the fundamental frequency, improving transient n 6-Phase, 90A to 120A Operation response while operating each phase at an optimal fre- n Output Power Good Indicator with Adaptive Blanking quency for efficiency and ease of thermal design. Light n 210kHz to 530kHz Per Phase, PLL, Fixed Frequency load efficiency is optimized by using a choice of output n Synchronizable (LTC3733-1) stage shedding or Burst Mode technology. n PWM, Stage Shedding or Burst Mode Operation A differential amplifier provides true remote sensing of both n OPTI-LOOP Compensation Minimizes C OUT the high and low sides of the output voltage at load points. n Adjustable Soft-Start Current Ramping Soft-start and a defeatable, timed short-circuit shutdown n Short-Circuit Shutdown Timer with Defeat Option protect the MOSFETs and the load. A foldback current n No CPU Detection circuit also provides protection for the external MOSFETs n 36-Lead 0.209 SSOP and 38-Lead (5mm 7mm) QFN under short-circuit or overload conditions. An all-1 VID U detector turns off the regulator after 1s timeout. APPLICATIO S , LTC and LT are registered trademarks of Linear Technology Corporation. n Burst Mode, OPTI-LOOP and PolyPhase are registered trademarks of Linear Technology High Performance Notebook Computers Corporation. AMD Opteron is a trademark of Advanced Micro Devices, Inc. n Servers, Desktop Computers and Workstations TYPICAL APPLICATIO V IN 5V TO 28V 5V V TG1 CC + L1 0.8H 22F 0.002 LTC3733-1 35V 10F SW1 2 BOOST1 D1 BG1 BOOST2 BOOST3 + SENSE1 0.1F SENSE1 SW3 SW2 SW1 V IN TG2 POWER GOOD INDICATOR PGOOD L2 0.8H 0.002 V OUT OPTIONAL SYN IN PLLIN SW2 0.8V TO 1.55V PLLFLTR 65A BG2 D2 PGND 5 VID BITS VID0-VID4 + SENSE2 ON/OFF RUN 680pF SENSE2 V IN I TH TG3 L3 0.8H 0.002 5k SS SW3 0.1F D3 SGND BG3 EAIN 100pF + SENSE3 C OUT + SENSE3 IN 470F + IN 4V 4 3733 F01 Figure 1. High Current Triple Phase Step-Down Converter 3733f 1 U ULTC3733/LTC3733-1 ABSOLUTE AXI U RATI GS (Note 1) Topside Driver Voltages (BOOST ) ............ 38V to 0.3V I Voltage ................................................ 2.4V to 0.3V N TH Switch Voltage (SW )................................... 32V to 5V Operating Ambient Temperature Range ....... 0C to 70C N Boosted Driver Voltage (BOOST SW ) .... 7V to 0.3V Junction Temperature (Note 2)............................. 125C N N Peak Output Current <1ms (TG , BG ) ..................... 5A Storage Temperature Range N N Supply Voltage (V ), PGOOD LTC3733CG .......................................65C to 150C CC Pin Voltages ................................................ 7V to 0.3V LTC3733CUHF-1 ...............................65C to 125C PLLIN, RUN, SS, Lead Temperature (LTC3733CG) PLLFLTR, FCB Voltages ............................. V to 0.3V (Soldering, 10 sec) ............................................... 300C CC UUW PACKAGE/ORDER I FOR ATIO TOP VIEW ORDER PART ORDER PART TOP VIEW 1 36 VID0 VID1 NUMBER NUMBER 2 35 PGOOD RUN LTC3733CG LTC3733CUHF-1 3 34 BOOST1 38 37 36 35 34 33 32 PLLFLTR PLLFLTR 1 31 SW1 4 33 TG1 FCB + FCB 2 30 BOOST2 5 32 SW1 IN + IN 3 29 TG2 6 31 BOOST2 IN IN 4 28 SW2 7 30 TG2 DIFFOUT DIFFOUT 5 27 V CC 8 29 SW2 EAIN EAIN DRV 6 26 CC 9 28 V SGND CC 39 SGND 7 25 BG1 + 10 27 BG1 SENSE1 + SENSE1 8 24 PGND 11 26 PGND SENSE1 UHF PART SENSE1 9 23 BG2 + 12 25 BG2 SENSE2 + MARKING SENSE2 10 22 BG3 13 24 BG3 SENSE2 SENSE2 11 21 SW3 37331 14 23 SW3 SENSE3 20 SENSE3 12 TG3 + 15 22 TG3 SENSE3 13 14 15 16 17 18 19 16 21 BOOST3 SS 17 20 VID4 I TH 18 19 VID3 VID2 UHF PACKAGE 38-LEAD (7mm 5mm) PLASTIC QFN G PACKAGE T = 125C, = 34C/W JMAX JA 36-LEAD PLASTIC SSOP EXPOSED PAD IS SGND (PIN 39) MUST BE SOLDERED TO PCB T = 125C, = 95C/W JMAX JA Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25C. V = V = V = 5V unless otherwise noted. A CC RUN SS SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loop + V Regulated Voltage at IN (Note 3) VID Code = 10011, V = 1.2V 1.067 1.075 1.083 V REGULATED ITH l 1.064 1.075 1.086 V V Maximum Current Sense Threshold V = 0.5V, V Open, 65 75 85 mV SENSEMAX EAIN ITH V V V = 0.8V, 1.55V l 62 75 88 mV SENSE1 , SENSE2 , SENSE3 I Current Match Worst-Case Error at V 5 5 % MATCH SENSE(MAX) 3733f 2 + PLLIN SENSE3 SS RUN I VID1 TH VID2 VID0 VID3 PGOOD VID4 BOOST1 BOOST3 TG1 U WWW