LTC3887/LTC3887-1/ LTC3887-2 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 3887/LTC3887-1/LTC3887-2 are dual, n Telemetry Read Back includes V , I , V , I , IN IN OUT OUT PolyPhase DC/DC synchronous step-down switching 2 Temperature, Duty Cycle and Faults regulator controllers with an I C-based PMBus compli- n Programmable Voltage, Current Limit, Digital ant serial interface. The controllers use a constant fre- Soft-Start/Stop, Sequencing, Margining, OV/UV quency, current mode architecture that is supported by and Frequency Synchronization (250kHz to 1MHz) LTpowerPlay a software development tool with graphical n 0.5% Output Voltage Accuracy Over Temperature user interface(GUI). n Integrated 16-Bit ADC n Switching frequency, channel phasing, output voltage, V Range: 0.5V to 5.5V (V , V ) OUT OUT0 OUT1 and device address can be programmed using external n Internal EEPROM and Fault Logging with ECC configuration resistors. Additionally, parameters can be n Integrated N-Channel MOSFET Gate Drivers (LTC3887) set via the digital interface or stored in EEPROM. Voltage, n Minimum On-Time 45ns current, internal/external temperature and fault status can n Wide V Range: 4.5V to 24V IN be read back through the bus interface. n Analog Current Mode Control Loop n Remote Differential Sense for PolyPhase Applications The LTC3887 has integrated gate drivers. The LTC3887-1 n Accurate PolyPhase Current Sharing for Up to Six Phases has three-state PWM pins to drive DrMOS power stages. n Available in a 40-Pin (6mm 6mm) QFN Package The LTC3887-2 has gate drivers and no LDO and supports n AEC-Q100 Qualified for Automotive Applications V up to 34V. The LTC3887 is an enhanced version of IN the LTC3880 with greater output voltage range and more APPLICATIONS digital features. Refer to Operation section for more detail. n High Current Distributed Power Systems All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6144194, 6177787, 6580258, 5408150, n Telecom, Datacom and Storage Systems 7420359. Licensed under U.S. Patent 7000125 and other related patents worldwide. n Intelligent Energy Efficient Power Regulation TYPICAL APPLICATION Dual 350kHz 3.3V/0.5V Step-Down Converter V IN Regulated Output Voltage vs 6V TO 16V 1F 10F Temperature, V = 0.5V OUT V INTV IN CC 0.5 TG0 TG1 0.1F 0.1F 0.4 LTC3887 BOOST0 BOOST1 0.3 V 0.56H 1H V OUT1 OUT0 3.3V 0.5V SW0 SW1 0.2 20A 20A 1.58k BG0 BG1 2k 0.1 0.22F 0.22F 0 + + I I SENSEO SENSE1 0.1 + I I SENSEO SENSE1 530F + 0.2 V V SENSEO SENSE1 V SENSEO 0.3 TSNS0 TSNS1 + 0.4 10nF 10nF 530F 2200pF 2200pF 0.5 4.99k 6.04k 50 30 10 10 30 50 70 90 110 I I THO TH1 TEMPERATURE (C) SDA GPIO0 FAULT MANAGEMENT 3887 TA01b SCL GPIO1 *SOME DETAILS OMITTED PMBus ALERT FOR CLARITY INTERFACE RUN0 V DD33 RUN1 V DD25 TO/FROM 1F 1F SHARE CLK OTHER LTC DEVICES SYNC GND WRITE PROTECT WP 3887 TA01a Rev. F 1 Document Feedback For more information www.analog.com V ERROR (%) OUTLTC3887/LTC3887-1/ LTC3887-2 TABLE OF CONTENTS Features ..................................................... 1 Responses to OT/UT Faults .....................................27 Applications ................................................ 1 Internal Overtemperature Fault/Warn Typical Application ........................................ 1 Response ...........................................................27 Description.................................................. 1 External Overtemperature and Undertemperature Table of Contents .......................................... 2 Fault Response ...................................................27 Absolute Maximum Ratings .............................. 4 Responses to External Faults .................................28 Pin Configuration .......................................... 4 Fault Logging ..........................................................28 Order Information .......................................... 5 Bus Timeout Protection ..........................................28 2 Electrical Characteristics ................................. 6 Similarity Between PMBus, SMBus and I C Typical Performance Characteristics .................. 10 2-Wire Interface ......................................................28 Pin Functions .............................................. 13 PMBus Serial Digital Interface ................................29 Block Diagram ............................................. 15 PMBus Command Summary ............................ 34 Operation................................................... 16 PMBus Commands .................................................34 Overview ................................................................. 16 *Data Format ..........................................................39 Main Control Loop .................................................. 17 Applications Information ................................ 40 EEPROM (NVM) ...................................................... 17 Current Limit Programming ....................................40 + Power Up and Initialization ..................................... 18 I and I Pins .........................................40 SENSE SENSE Soft-Start ................................................................ 18 Low Value Resistor Current Sensing ....................... 41 Sequencing ............................................................. 19 Inductor DCR Current Sensing ................................42 EVENT-Based Sequencing ...................................... 19 Slope Compensation and Inductor Peak Current ....43 Shutdown ...............................................................20 Inductor Value Calculation ......................................43 Light Load Current Operation .................................20 Inductor Core Selection ..........................................44 Switching Frequency and Phase .............................21 Power MOSFET and Schottky Diode (Optional) Output Voltage Sensing ..........................................21 Selection .................................................................44 Current Sensing ......................................................21 Variable Delay Time, Soft-Start and Output Voltage PolyPhase Load Sharing .........................................22 Ramping .................................................................45 External/Internal Temperature Sense ......................22 Digital Servo Mode .................................................46 RCONFIG (Resistor Configuration) Pins ..................23 Soft Off (Sequenced Off) ........................................46 Fault Detection and Handling .................................. 24 INTV Regulator.................................................... 47 CC Internal EEPROM with CRC Protection Topside MOSFET Driver Supply (C , D ) (LTC3887, B B and ECC ..............................................................25 LTC3887-2) ............................................................. 47 Serial Interface .......................................................25 Undervoltage Lockout .............................................48 Communication Protection ................................25 C and C Selection ...........................................48 IN OUT Device Addressing ..................................................25 Fault Conditions ......................................................49 Responses to V and I Faults ........................26 Open-Drain Pins .....................................................49 OUT OUT Output Overvoltage Fault Response ...................26 Phase-Locked Loop and Frequency Synchronization 50 Output Undervoltage Response .........................26 Minimum On-Time Considerations.......................... 51 Peak Output Overcurrent Fault Response ...........27 Responses to Timing Faults ....................................27 Responses to V OV Faults ....................................27 IN Rev.F 2 For more information www.analog.com