POWER LOSS (W) LTC3880/LTC3880-1 Dual Output PolyPhase Step-Down DC/DC Controller with Digital Power System Management FEATURES DESCRIPTION 2 n PMBus/I C Compliant Serial Interface The LTC 3880/LTC3880-1 are dual, PolyPhase DC/DC n Telemetry Read Back includes V , I , V , I , synchronous step-down switching regulator controllers IN IN OUT OUT 2 Temperature and Faults with an I C-based PMBus compliant serial interface. n Programmable Voltage, Current Limit, Digital The controllers use a constant frequency, current mode Soft-Start/Stop, Sequencing, Margining, OV/UV architecture that is supported by LTpowerPlay software and Frequency Synchronization (250kHz to 1MHz) development tool with graphical user interface (GUI). n 0.5% Output Voltage Accuracy Over Temperature Switching frequency, output voltage, and device address n Integrated 16-Bit ADC can be programmed using external configuration resistors. n Internal EEPROM with ECC and Fault Logging Parameters can be set via the digital interface or stored in n Integrated Powerful N-Channel MOSFET Gate Drivers EEPROM. Voltage, current, internal/external temperature Power Conversion and fault status can be read back through the bus interface. n Wide V Range: 4.5V to 24V IN The LTC3880 incorporates a 5V linear regulator while the n V Range: 0.5V to 5.4V (4V on V ) OUT OUT0 LTC3880-1 uses an external 5V supply for minimum power n Analog Current Mode Control Loop loss. See comparison to LTC3887 below. n Accurate PolyPhase Current Sharing for Up to 6 Phases V Max Fast ADC Mode OUT n Available in a 40-Pin (6mm 6mm) QFN Package Start-Up Time V for 1 Parameter OUT0/1 n AEC-Q100 Qualified for Automotive Applications LTC3887/LTC3887-1 35ms 5.5V/5.5V Yes LTC3880/LTC3880-1 120ms 4V/5.4V No APPLICATIONS All registered trademarks and trademarks are the property of their respective owners. Protected n High Current Distributed Power Systems by U.S. Patents including 5481178, 5705919, 5929620, 6144194, 6177787, 6580258, 5408150, 7420359. Licensed under U.S. Patent 7000125 and other related patents worldwide. n Telecom, Datacom and Storage Systems n Intelligent Energy Efficient Power Regulation TYPICAL APPLICATION V IN 1F 10F Efficiency and Power Loss V INTV IN CC vs Load Current TG0 TG1 0.1F 0.1F 100 6 LTC3880 V = 12V IN BOOST0 BOOST1 90 1.0H 0.56H V V = 1.8V V OUT1 OUT OUT0 5 3.3V SW0 SW1 1.8V 80 20A 15A 2.15k 1.74k BG0 BG1 70 4 0.2F 0.2F PGND 60 + + I I SENSEO SENSE1 50 3 + I I SENSEO SENSE1 530F + 40 V V SENSEO SENSE1 2 V SENSEO 30 TSNS0 TSNS1 + 20 10nF 10nF 530F 1 2200pF 2200pF 10 6.04k 4.99k I I THO TH1 0 0 0.01 0.1 1 10 100 SDA GPIO0 FAULT MANAGEMENT LOAD CURRENT (A) SCL GPIO1 SOME DETAILS OMITTED PMBus ALERT FOR CLARITY 3880 TA01b INTERFACE RUN0 V DD33 RUN1 V DD25 TO/FROM SHARE CLK 1F 1F SYNC OTHER LTC DEVICES SGND WP WRITE PROTECT 3880 TA01a Rev. H 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC3880/LTC3880-1 TABLE OF CONTENTS Features ..................................................... 1 Responses to Timing Faults ....................................29 Applications ................................................ 1 Responses to V OV Faults ....................................29 IN Typical Application ........................................ 1 Responses to OT/UT Faults .....................................29 Description.................................................. 1 Overtemperature Fault ResponseInternal ......29 Table of Contents .......................................... 2 Overtemperature and Undertemperature Absolute Maximum Ratings .............................. 4 Fault ResponseExternals ...............................29 Pin Configuration .......................................... 4 Responses to External Faults .................................29 Order Information .......................................... 4 Bus Timeout Failure ................................................30 2 Electrical Characteristics ................................. 5 Similarity Between PMBus, SMBus and I C Typical Performance Characteristics .................. 11 2-Wire Interface ......................................................30 Pin Functions .............................................. 15 PMBus Serial Digital Interface ................................31 Block Diagram ............................................. 17 PMBus Command Summary ............................ 34 Operation................................................... 18 PMBus Commands .................................................34 Overview ................................................................. 18 *Data Format ..........................................................39 Main Control Loop .................................................. 18 Applications Information ................................ 40 EEPROM ................................................................. 19 Current Limit Programming ....................................40 + Power Up and Initialization .....................................20 I and I Pins .........................................40 SENSE SENSE Soft-Start ................................................................20 Low Value Resistor Current Sensing ....................... 41 Sequencing .............................................................21 Inductor DCR Current Sensing ................................42 Voltage-Based Sequencing .....................................21 Slope Compensation and Inductor Peak Current ....43 Shutdown ...............................................................21 Inductor Value Calculation ......................................43 Light Load Current Operation .................................22 Inductor Core Selection ..........................................44 Switching Frequency and Phase .............................22 Power MOSFET and Schottky Diode (Optional) Output Voltage Sensing ..........................................23 Selection .................................................................44 Current Sensing ......................................................23 Variable Delay Time, Soft-Start and Output Voltage Load Sharing .......................................................... 24 Ramping .................................................................45 External/Internal Temperature Sense ...................... 24 Digital Servo Mode .................................................46 RCONFIG (Resistor Configuration) Pins ..................25 Soft Off (Sequenced Off) ........................................46 Fault Detection and Handling ..................................25 INTV Regulator.................................................... 47 CC Internal Memory with CRC and ECC ...................26 Topside MOSFET Driver Supply (C , D ) ................48 B B Serial Interface .......................................................27 Undervoltage Lockout .............................................48 Communication Failure ......................................27 C and C Selection ...........................................48 IN OUT Device Addressing ..................................................27 Fault Conditions ......................................................49 Responses to V and I Faults ........................28 Open-Drain Pins .....................................................50 OUT OUT Output Overvoltage Fault Response ...................28 Phase-Locked Loop and Frequency Output Undervoltage Response .........................28 Synchronization ......................................................50 Peak Output Overcurrent Fault Response ...........28 Minimum On-Time Considerations.......................... 51 Rev. H 2 For more information www.analog.com