POWERLOSS (W) LTC3882 Dual Output PolyPhase Step-Down DC/DC Voltage Mode Controller with Digital Power System Management FEATURES DESCRIPTION 2 n PMBus/I C Compliant Serial Interface The LTC 3882 is a dual, PolyPhase DC/DC synchronous Monitor Voltage, Current, Temperature and Faults step-down switching regulator controller with PMBus Digitally Programmable Voltage, Current Limit, compliant serial interface. It uses a constant frequency, Soft-Start/Stop, Sequencing, Margining, AVP leading-edge modulation, voltage mode architecture for and UV/OV Thresholds excellent transient response and output regulation. Each n 3V VINSNS 38V, 0.5V V 5.25V PWM channel can produce output voltages from 0.5V to OUT n 0.5% Output Voltage Accuracy 5.25V using a wide range of 3.3V compatible power stages, n Programmable PWM Frequency or External Clock including power blocks, DrMOS or discrete FET drivers. Synchronization from 250kHz to 1.25MHz Up to four LTC3882s can operate in parallel for 2-, 3-, 4-, n Accurate PolyPhase Current Sharing 6- or 8-phase operation. n Internal EEPROM with Fault Logging LTC3882 system configuration and monitoring is supported n IC Supply Range: 3V to 13.2V by the LTpowerPlay software tool. The devices serial n Resistor or Inductor DCR Current Sensing interface can be used to read back input voltage, output n Optional Resistor Programming for Key Parameters voltage and current, temperature and fault status. A wide n 40-Pin (6mm 6mm) QFN Package range of operating parameters can be set via the digital interface or stored in internal EEPROM for use at power APPLICATIONS up. Switching frequency and phase, output voltage and n High Current Distributed Power Systems device address can also be programmed using external n Servers, Network and Storage Equipment configuration resistors. n Intelligent Energy Efficient Power Regulation L, LT, LTC, LTM, Linear Technology,the Linear logo and PolyPhase are registered trademarks and LTpowerPlay is a trademark of Linear Technology Corporation. All other trademarks are the n Industrial/Telecom/ATE Systems property of their respective owners. Protected by U.S. Patents, including 5396245, 5859606, 6144194, 6937178, 7420359 and 7000125. TYPICAL APPLICATION V IN 7V TO 13.2V V VINSNS + CC V SENSE0 Efficiency and Power Loss vs FB0 V FDMF5820A IN Load Current LTC3882 92 13 V OUT PWM SW 1V 91 SDA COMP0 80A 90 11 SCL COMP1 89 ALERT TO/FROM GND PWM0 88 9 MCU RUN0 TSNS0 87 RUN1 + 86 7 WP I SENSE0 GPIO0 I 85 TO/FROM SENSE0 + EXTERNAL DEVICES GPIO1 V SENSE1 84 5 TO/FROM OTHER SHARE CLK I SENSE1 83 OTHER PHASES + SYNC I V = 12V SENSE1 82 3 IN V = 1V OUT 81 I FDMF5820A AVG0 V SYNC = 500kHz IN 80 1 SW I AVG1 PWM1 PWM 0 10 20 30 40 50 60 70 80 GND LOAD CURRENT (A) TSNS1 3882 TA01b I AVG GND V SENSE0 GND INDUCTORS: COOPER FP1007R1-R22 3882 TA01a SOME DETAILS OMITTED FOR CLARITY 3882f 1 For more information www.linear.com/LTC3882 EFFICIENCY (%)LTC3882 TABLE OF CONTENTS Features .............................................................1 Serial Bus Timeout ......................................................34 Applications ........................................................1 Serial Communication Errors ......................................34 Typical Application ................................................1 PMBus Command Summary ................................... 35 Description..........................................................1 PMBus Commands ......................................................35 Absolute Maximum Ratings ......................................4 Data Formats ...............................................................35 Order Information ..................................................4 Applications Information ....................................... 40 Electrical Characteristics .........................................4 Efficiency Considerations ............................................40 Pin Configuration ..................................................4 PWM Frequency and Inductor Selection .....................40 Typical Performance Characteristics ...........................8 Power MOSFET Selection ............................................41 Pin Functions ..................................................... 11 MOSFET Driver Selection ............................................42 Block Diagram .................................................... 13 Using PWM Protocols .................................................42 Test Circuit ........................................................ 14 C Selection ...............................................................43 IN Timing Diagram .................................................. 14 C Selection .............................................................44 OUT Feedback Loop Compensation ....................................44 Operation.......................................................... 14 Overview .....................................................................14 PCB Layout Considerations .........................................46 Main Control Loop .......................................................15 Output Current Sensing ...............................................47 Power-Up and Initialization..........................................17 Output Voltage Sensing ...............................................49 Soft-Start ....................................................................18 Soft-Start and Stop .....................................................49 Time-Based Output Sequencing ..................................18 Time-Based Output Sequencing and Ramping ............50 Output Ramping Control .............................................18 Voltage-Based Output Sequencing ..............................51 Voltage-Based Output Sequencing ..............................18 Using Output Voltage Servo ........................................52 Output Disable .............................................................18 Using AVP ...................................................................52 Minimum Output Disable Times ..................................19 PWM Frequency Synchronization ...............................53 Output Short Cycle ......................................................19 PolyPhase Operation and Load Sharing ......................54 Light Load Current Operation ......................................19 External Temperature Sense .......................................56 Switching Frequency and Phase .................................19 Resistor Configuration Pins ........................................58 PolyPhase Load Sharing .............................................20 Internal Regulator Outputs ..........................................59 Active Voltage Positioning ...........................................20 IC Junction Temperature .............................................60 Input Supply Monitoring .............................................20 Derating EEPROM Retention at Temperature ..............60 Configuring Open-Drain Pins ......................................60 Output Voltage Sensing and Monitoring .....................20 Output Current Sensing and Monitoring .....................21 PMBus Communication and Command Processing ....61 External and Internal Temperature Sense....................21 Status and Fault Log Management ..............................62 Resistor Configuration Pins ........................................21 LTpowerPlay An Interactive Digital Power GUI .........63 Internal EEPROM with CRC .........................................22 Interfacing to the DC1613 ............................................63 Fault Detection ............................................................22 Design Example ...........................................................64 Input Supply Faults .....................................................22 PMBus COMMAND DETAILS .................................... 66 Hardwired PWM Response to V Faults ..................22 Addressing and Write Protect ..........................................66 OUT Power Good Indication ................................................23 PAGE ...........................................................................66 Hardwired PWM Response to I Faults ...................23 PAGE PLUS WRITE ...................................................66 OUT Hardwired PWM Response to Temperature Faults ......23 PAGE PLUS READ .....................................................67 Hardwired PWM Response to Timing Faults ...............23 WRITE PROTECT .......................................................67 External Faults .............................................................24 MFR ADDRESS ..........................................................68 Fault Handling .............................................................24 MFR RAIL ADDRESS ................................................68 Status Registers and ALERT Masking .........................24 General Device Configuration ..........................................68 Mapping Faults to GPIO Pins .......................................26 PMBUS REVISION ......................................................68 Other GPIO Uses .........................................................26 CAPABILITY ................................................................68 Fault Logging ...............................................................26 MFR CONFIG ALL LTC3882 .....................................69 Factory Default Operation ...........................................29 On, Off and Margin Control ..............................................69 Serial Interface ............................................................30 ON OFF CONFIG .........................................................69 Serial Bus Addressing .................................................30 OPERATION .................................................................70 3882f 2 For more information www.linear.com/LTC3882