LTC7851/LTC7851-1 Quad Output, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing FEATURES DESCRIPTION n Operates with Power Blocks, DrMOS or External The LTC 7851/LTC7851-1 are quad output multiphase syn- Gate Drivers and MOSFETs chronous step-down switching regulator controllers that n Voltage Mode Control with Accurate Current Sharing employ a constant frequency voltage mode architecture. n 0.75% 0.6V Voltage Reference They maintain excellent current balance between channels n Quad Differential Output Voltage Sense Amplifiers when paralleled with their internal current sharing loop. n Multiphase Capability Lossless DCR or a low value R is used for output SENSE n Phase-Lockable Fixed Frequency 250kHz to 2.25MHz current sensing. Multiple LTC7851/LTC7851-1 devices can n Lossless Current Sensing Using Inductor DCR or be used for high phase count operation. Precision Current Sensing with Sense Resistor or A very low offset, high bandwidth error amplifier, combined DrMOS with Integrated Current Sensing with remote output voltage sensing, provides excellent n V Range: 3V to 5.5V CC transient response and output regulation. The LTC7851/ n V Range: 0.6V to V 0.5V OUT CC LTC7851-1 operates with a V supply voltage from 3V to CC n Power Good Output Voltage Monitor 5.5V and is designed for step-down conversion with V IN n Output Voltage Tracking Capability with Soft-Start from 3V to 27V* and produces an output voltage from n Available in 58-Lead 5mm 9mm QFN Package 0.6V to V 0.5V. CC APPLICATIONS The LTC7851-1 is identical to the LTC7851 except it has n High Current Distributed Power Systems a lower current sense amplifier gain, making it ideal for n DSP, FPGA and ASIC Supplies DrMOS devices with internal current sense. n Datacom, Telecom and Computing Systems All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents, including 6144194, 5055767. *See Note 5. TYPICAL APPLICATION Dual-Output Converter: 1V/90A and 1.5V/30A with DrMOS V IN 7V TO 14V VINSNS 0.25H 0.25H DrMOSDrMOS PWM3 PWM2 DrMOSDrMOS 3.57k 3.57k LTC7851 0.22F 0.22F ISNS3P ISNS2P ISNS3N ISNS2N V CC V FB2,3 V CC CC 5V 1F 100k 100k 0.25H 0.25H PGOOD4 PGOOD1 V V OUT2 OUT1 DrMOS PWM4 PWM1 DrMOS 1.5V/30A 1.0V/90A + + 100F RUN1 TRACK/SS1 100F 330F 330F 3.57k 3.57k x 2 x 6 RUN2 TRACK/SS2 0.22F 0.22F x 3 x 9 RUN3 TRACK/SS3 PINS NOT USED ISNS4P ISNS1P 15k 10k IN THIS CIRCUIT: ISNS4N ISNS1N CLKIN VSNSP4 VSNSP1 CLKOUT VSNSN4 VSNSN1 VSNSP2 VSNSOUT4 VSNSOUT1,2,3 VSNSP3 6.04k 4.02k 3.3nF 3.3nF 10k 15k COMP4 COMP1,2,3 VSNSN2 10k 10k FB4 FB1 VSNSN3 332 2.2nF 100pF 100pF 2.2nF 332 FREQ I PGOOD2 AVG1,2,3 I I PGOOD3 LIM4 LIM1,2,3 SGND RUN4 30.9k 42.2k 42.2k 100pF I AVG4 7851 TA01 TRACK/SS4 Rev A 1 Document Feedback For more information www.analog.comLTC7851/LTC7851-1 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V Voltage .............................................. 0.3V to 6.5V CC VINSNS Voltage ........................................ 0.3V to 30V RUN1, RUN2, RUN3, 58 57 56 55 54 53 52 51 50 49 RUN4 Voltage ............................0.3V to (V +0.3V) CC COMP1 1 48 I LIM1 ISNS1P, ISNS1N, VSNSP1 2 47 I AVG1 ISNS2P, ISNS2N ....................... 0.3V to (V + 0.1V) CC VSNSN1 46 ISNS1P 3 ISNS3P, ISNS3N, VSNSOUT1 4 45 ISNS1N ISNS4P, ISNS4N ....................... 0.3V to (V + 0.1V) SGND 5 44 ISNS2N CC VSNSOUT2 6 43 ISNS2P All Other Pin Voltages ...................0.3V to (V + 0.3V) CC VSNSN2 7 42 I AVG2 Operating Junction Temperature Range ... 40 to 125C VSNSP2 8 I 41 LIM2 Storage Temperature Range .................. 65C to 150C COMP2 9 40 TRACK/SS2 59 FB2 10 39 VINSNS SGND V 11 38 PGOOD2 CC FB3 12 37 TRACK/SS3 COMP3 13 36 I LIM3 VSNSP3 14 35 I AVG3 VSNSN3 15 34 ISNS3P VSNSOUT3 16 33 ISNS3N VSNSOUT4 17 32 ISNS4N VSNSN4 18 31 ISNS4P VSNSP4 19 30 I AVG4 20 21 22 23 24 25 26 27 28 29 UHH PACKAGE 58-LEAD (5mm 9mm) PLASTIC QFN LEAD PITCH 0.4mm = 49C/W, = 15.5C/W JA JC EXPOSED PAD (PIN 59) IS SGND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC7851EUHH PBF LTC7851EUHH TRPBF 7851 58-LEAD (5mm 9mm) Plastic QFN 40C to 125C LTC7851IUHH PBF LTC7851IUHH TRPBF 7851 58-LEAD (5mm 9mm) Plastic QFN 40C to 125C LTC7851EUHH-1 PBF LTC7851EUHH-1 TRPBF 78511 58-LEAD (5mm 9mm) Plastic QFN 40C to 125C LTC7851IUHH-1 PBF LTC7851IUHH-1 TRPBF 78511 58-LEAD (5mm 9mm) Plastic QFN 40C to 125C Consult ADI Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. Rev A 2 For more information www.analog.com COMP4 FB1 FB4 TRACK/SS1 TRACK/SS4 FREQ CLKIN RUN4 PWM4 CLKOUT PGOOD4 RUN1 PWM3 PWM1 RUN3 RUN2 PWM2 PGOOD3 I PGOOD1 LIM4