LTC3861-1 Dual, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing Fea T Descrip T n Operates with Power Blocks, DrMOS or External The LTC 3861-1 is a dual PolyPhase synchronous step- Gate Drivers and MOSFETs down switching regulator controller for high current n Constant-Frequency Voltage Mode Control with distributed power systems, digital signal processors, and Accurate Current Sharing other telecom and industrial DC/DC power supplies. It uses n 0.75% 0.6V Voltage Reference a constant-frequency voltage mode architecture combined n with very low offset, high bandwidth error amplifiers and Differential Remote Output Voltage Sense Amplifier n a remote output sense differential amplifier for excellent Multiphase CapabilityUp to 12-Phase Operation n transient response and output regulation. Programmable Current Limit n Safely Powers a Prebiased Load The controller incorporates lossless inductor DCR current n Programmable or PLL-Synchronizable Switching sensing to maintain current balance between phases and to Frequency Up to 2.25MHz provide overcurrent protection. The chip operates from a n Lossless Current Sensing Using Inductor DCR or V supply between 3V and 5.5V and is designed for step- CC Precision Current Sensing with Sense Resistor down conversion from V between 3V and 24V to output IN n V Range: 3V to 5.5V CC voltages between 0.6V and V 0.5V. CC n V Range: 3V to 24V IN Inductor current reversal is disabled during soft-start to n Power Good Output Voltage Monitor safely power prebiased loads. The constant operating n Output Voltage Tracking Capability frequency can be synchronized to an external clock or n Programmable Soft-Start linearly programmed from 250kHz to 2.25MHz. Up to six n Available in a 32-Pin 5mm 5mm QFN Package LTC3861-1 controllers can operate in parallel for 1-, 2-, 3-, 4-, 6- or 12-phase operation. a T The LTC3861-1 is pin-to-pin compatible with the LTC3860. n High Current Distributed Power Systems It is available in a 32-pin 5mm 5mm QFN package. The n DSP, FPGA and ASIC Supplies LTC3861is a 36-pin QFN version of the LTC3861-1, which n Datacom and Telecom Systems has dual differential output voltage sense amplifiers. n Industrial Power Supplies L, LT, LTC, LTM, PolyPhase, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 6144194, 5055767 Typical a T V , 7V TO 14V IN LTC4449 180F IN GND V , 7V TO 14V IN V TG V CC LOGIC V TS CC V CC V VINSNS PWM1 CC 0.47H BOOST BG FREQ 1F FB2 28.7k LTC3861-1 59k 0.22F RUN1,2 I LIM2 2.87k I LIM1 VSNSOUT ISNS1P V 0.22F OUT V VSNSP OUT ISNS1N 1.2V VSNSN 330F 100F ISNS2N 60A CONFIG 0.22F 6 4 ISNS2P V IN 1nF 2.87k LTC4449 PWM2 IN GND 20k 221 0.47H V FB1 V TG CC LOGIC I AVG 38611 TA01 V TS CC COMP1,2 SS1,2 SGND CLKIN BOOST BG 1nF 20k 13k 220pF 0.1F 100pF 0.22F 38611fb 1 For more information www.linear.com/LTC3861-1 ion pplica ions pplica ion uresLTC3861-1 a Te m aximum r a T p in c F T (Note 1) V Voltage .................................................. 0.3V to 6V CC TOP VIEW VINSNS Voltage ......................................... 0.3V to 30V RUN1, RUN2 Voltage ........................0.3V to V + 0.3V CC ISNS1P, ISNS1N, 32 31 30 29 28 27 26 25 V 1 24 RUN1 ISNS2P, ISNS2N ........................... 0.3V to (V + 0.1V) CC CC FB1 2 23 I LIM1 All Other Pins ................................0.3V to (V + 0.3V) CC COMP1 ISNS1P 3 22 Operating Junction Temperature Range VSNSOUT 4 21 ISNS1N 33 (Notes 2, 3) ............................................ 40C to 125C SGND VSNSN 5 20 ISNS2N Storage Temperature Range .................. 65C to 150C VSNSP 6 19 ISNS2P COMP2 7 18 I LIM2 FB2 8 17 RUN2 9 10 11 12 13 14 15 16 UH PACKAGE 32-LEAD (5mm 5mm) PLASTIC QFN T = 125C, = 34C/W JMAX JA EXPOSED PAD (PIN 33) IS SGND, MUST BE SOLDERED TO PCB o r Der i n F T LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3861EUH-1 PBF LTC3861EUH-1 TRPBF 38611 32-Lead (5mm 5mm) Plastic QFN 40C to 125C LTC3861IUH-1 PBF LTC3861IUH-1 TRPBF 38611 32-Lead (5mm 5mm) Plastic QFN 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: