LTC3860 Dual, Multiphase Step-Down Voltage Mode DC/DC Controller with Current Sharing FEATURES DESCRIPTION n Operates with Power Blocks, DRMOS or External The LTC 3860 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 Differential Remote Output Voltage Sense Ampli er with very low offset, high bandwidth error ampli ers and n Multiphase CapabilityUp to 12-Phase Operation a remote output sense differential ampli er for excellent n Programmable Current Limit transient response and output regulation. 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 1.25MHz 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 n The TRACK/SS pins provide programmable soft-start or Power Good Output Voltage Monitor n tracking functions. Inductor current reversal is disabled Output Voltage Tracking Capability n during soft-start to safely power prebiased loads. The con- Programmable Soft-Start n stant operating frequency can be synchronized to an exter- Available in a 32- Pin 5mm 5mm QFN Package nal clock or linearly programmed from 250kHz to 1.25MHz. APPLICATIONS Up to six LTC3860 controllers can operate in parallel for 1-, 2-, 3-, 4-, 6- or 12-phase operation. n High Current Distributed Power Systems n Digital Signal Processor and ASIC Supplies The LTC3860 is available in a 32-pin 5mm 5mm QFN n Telecom Systems package. n Industrial Power Supplies L, LT, LTC, LTM, PolyPhase, Module, Linear Technology and the Linear logo are registered trademarks and No R is a trademark of Linear Technology Corporation. All other SENSE trademarks are the property of their respective owners. Protected by U.S. Patents, including 6144194, 5055767 TYPICAL APPLICATION V IN LTC4449 PWM1 IN GND TG1 0.3H V V TG LOGIC V CC IN SW1 V TS CC 470F BOOST BG PWM1 BG1 VINSNS 50k 0.22F V V RUN1,2 CC CC 2.32k I FREQ 1F LIM1 V FB2 ISNS1P 0.22F OUT V OUT 1.2V I ISNS1N LIM2 LTC3860 330F FB1 ISNS2N 50A 0.22F s 4 COMP1,2 ISNS2P 1nF V SS1,2 IN 2.32k 33pF LTC4449 20k 220 VSNSOUT PWM2 PWM2 IN GND TG2 VSNSN 0.3H V V TG CC LOGIC VSNSP I SW2 AVG 3860 TA01 V TS 20k 0.1F CC SGND CLKIN 220pF BOOST BG 12.7k BG2 100pF 0.22F 3860fc 1LTC3860 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) V Voltage .................................................. 0.3V to 6V CC TOP VIEW VINSNS Voltage ......................................... 0.3V to 30V VSNSN Voltage ............................................ 0.3V to 2V 32 31 30 29 28 27 26 25 RUN Voltage ................................................ 0.3V to 6V V 1 24 RUN1 CC ISNS1P, ISNS1N, FB1 2 23 I LIM1 ISNS2P, ISNS2N ...........................0.3V to (V + 0.1V) CC COMP1 3 22 ISNS1P All Other Voltages .........................0.3V to (V + 0.3V) CC VSNSOUT 4 21 ISNS1N 33 Operating Junction Temperature Range SGND VSNSN 5 20 ISNS2N (Note 3) .................................................. 40C to 125C VSNSP ISNS2P 6 19 Storage Temperature Range ................... 65C to 125C COMP2 7 18 I LIM2 FB2 8 17 RUN2 9 10 11 12 13 14 15 16 UH PACKAGE 32-LEAD (5mm s 5mm) PLASTIC QFN T = 125C, = 34C/W JMAX JA EXPOSED PAD (PIN 33) IS SGND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3860EUH PBF LTC3860EUH TRPBF 3860 32-Lead (5mm 5mm) Plastic QFN 40C to 125C LTC3860IUH PBF LTC3860IUH TRPBF 3860 32-Lead (5mm 5mm) Plastic QFN 40C to 125C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: