Datasheet LTC3860 (Analog Devices)

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 Amplifi er
with very low offset, high bandwidth error amplifi ers and n
Multiphase Capability—Up to 12-Phase Operation
a remote output sense differential amplifi 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
VCC supply between 3V and 5.5V and is designed for step-
Precision Current Sensing with Sense Resistor
down conversion from VIN between 3V and 24V to output n VCC Range: 3V to 5.5V voltages between 0.6V and VCC – 0.5V. n VIN Range: 3V to 24V n Power Good Output Voltage Monitor The TRACK/SS pins provide programmable soft-start or n Output Voltage Tracking Capability tracking functions. Inductor current reversal is disabled n Programmable Soft-Start during soft-start to safely power prebiased loads. The con- n Available in a 32- Pin 5mm × 5mm QFN Package stant operating frequency can be synchronized to an exter- 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, μModule, Linear Technology and the Linear logo are registered trademarks and No RSENSE is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 6144194, 5055767
TYPICAL APPLICATION
VIN LTC4449 PWM1 IN GND TG1 V V 0.3μH V CC LOGIC TG IN SW1 VCC TS 470μF BOOST BG PWM1 BG1 VINSNS 50k 0.22μF VCC VCC RUN1,2 2.32k FREQ I 1μF LIM1 FB2 ISNS1P 0.22μF V V OUT OUT ILIM2 ISNS1N 1.2V FB1 LTC3860 ISNS2N 330μF 50A COMP1,2 ISNS2P 0.22μF s4 1nF SS1,2 VIN 2.32k 20k 220Ω 33pF LTC4449 VSNSOUT PWM2 VSNSN PWM2 IN GND TG2 0.3μH VSNSP VCC V I LOGIC TG AVG SW2 20k 0.1μF V TS 3860 TA01 220pF SGND CLKIN CC 12.7k BOOST BG 100pF BG2 0.22μF 3860fc 1 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS FUNCTIONAL DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS