Datasheet LTC3882 (Analog Devices)

LTC3882 Dual Output PolyPhase Step-Down DC/DC Voltage Mode Controller with Digital Power System Management
FEATURES DESCRIPTION
n
PMBus/I2C Compliant Serial Interface
The LTC®3882 is a dual, PolyPhase DC/DC synchronous n
Monitor Voltage, Current, Temperature and Faults
step-down switching regulator controller with PMBus n
Digitally Programmable Voltage, Current Limit,
compliant serial interface. It uses a constant frequency,
Soft-Start/Stop, Sequencing, Margining, AVP and
leading-edge modulation, voltage mode architecture for
UV/OV Thresholds
excellent transient response and output regulation. Each n
3V ≤ VINSNS ≤ 38V, 0.5V ≤ V
PWM channel can produce output voltages from 0.5V to
OUT ≤ 5.25V
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. Up to four LTC3882s can operate in parallel for 2-, 3-, 4-,
Synchronization from 250kHz to 1.25MHz
n 6- or 8-phase operation.
Accurate PolyPhase
®
Current Sharing
n
Internal EEPROM with Fault Logging and ECC
LTC3882 system configuration and monitoring is sup- n IC Supply Range: 3V to 13.2V ported by the LTpowerPlay® software tool. The device’s n Resistor or Inductor DCR Current Sensing serial interface can be used to read back input voltage, n Optional Resistor Programming for Key Parameters output voltage and current, temperature and fault status. n 40-Pin (6mm × 6mm) QFN Package A wide range of operating parameters can be set via the n AEC-Q100 Qualified for Automotive Applications digital interface or stored in internal EEPROM for use at power up. Switching frequency and phase, output volt-
APPLICATIONS
age and device address can also be programmed using n High Current Distributed Power Systems external configuration resistors. n All registered trademarks and trademarks are the property of their respective owners. Protected Servers, Network and Storage Equipment by U.S. Patents, including 5396245, 5859606, 6144194, 6937178, 7420359 and 7000125. n Intelligent Energy Efficient Power Regulation n Industrial/Telecom/ATE Systems
TYPICAL APPLICATION
VIN 7V TO 13.2V VCC VINSNS V +
Efficiency and Power Loss vs
SENSE0
Load Current
FB0 FDMF5820DC VIN 92 13 LTC3882 PWM V SW OUT 91 1V SDA COMP0 80A 90 11 SCL COMP1 89 POWERLOSS (W) TO/FROM ALERT PWM0 GND 88 9 MCU RUN0 TSNS0 87 RUN1 86 7 WP I + SENSE0 85 TO/FROM GPIO0 I – SENSE0 EFFICIENCY (%) EXTERNAL DEVICES GPIO1 V + 84 5 SENSE1 TO/FROM OTHER SHARE_CLK I – 83 SENSE1 OTHER PHASES SYNC I + 82 VIN = 12V 3 SENSE1 81 VOUT = 1V IAVG0 V FDMF5820DC SYNC = 500kHz IN SW 80 1 IAVG1 PWM1 PWM 0 10 20 30 40 50 60 70 80 GND LOAD CURRENT (A) TSNS1 IAVG_GND 3882 TA01b V – SENSE0 GND INDUCTORS: COOPER FP1007R1-R22 3882 TA01a SOME DETAILS OMITTED FOR CLARITY Rev. C For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Block Diagram Test Circuit Timing Diagram Operation Overview Main Control Loop Power-Up and Initialization Soft-Start Time-Based Output Sequencing Output Ramping Control Voltage-Based Output Sequencing Output Disable Minimum Output Disable Times Output Short Cycle Light Load Current Operation Switching Frequency and Phase PolyPhase Load Sharing Active Voltage Positioning Input Supply Monitoring Output Voltage Sensing and Monitoring Output Current Sensing and Monitoring External and Internal Temperature Sense Resistor Configuration Pins Internal EEPROM with ECC and CRC Fault Detection Input Supply Faults Hardwired PWM Response to VOUT Faults Power Good Indication Hardwired PWM Response to IOUT Faults Hardwired PWM Response to Temperature Faults Hardwired PWM Response to Timing Faults External Faults Fault Handling Status Registers and ALERT Masking Mapping Faults to GPIO Pins Other GPIO Uses Fault Logging Factory Default Operation Serial Interface Serial Bus Addressing Serial Bus Timeout Serial Communication Errors PMBus Command Summary PMBus Commands Data Formats Applications Information Efficiency Considerations PWM Frequency and Inductor Selection Power MOSFET Selection MOSFET Driver Selection Using PWM Protocols CIN Selection COUT Selection Feedback Loop Compensation PCB Layout Considerations Output Current Sensing Output Voltage Sensing Soft-Start and Stop Time-Based Output Sequencing and Ramping Voltage-Based Output Sequencing Using Output Voltage Servo Using AVP PWM Frequency Synchronization PolyPhase Operation and Load Sharing External Temperature Sense Resistor Configuration Pins Internal Regulator Outputs IC Junction Temperature Derating EEPROM Retention at Temperature Configuring Open-Drain Pins PMBus Communication and Command Processing Status and Fault Log Management LTpowerPlay – An Interactive Digital Power GUI Interfacing to the DC1613 Design Example PMBus COMMAND DETAILS Addressing and Write Protect PAGE PAGE_PLUS_WRITE PAGE_PLUS_READ WRITE_PROTECT MFR_ADDRESS MFR_RAIL_ADDRESS General Device Configuration PMBUS_REVISION CAPABILITY On, Off and Margin Control ON_OFF_CONFIG MFR_CONFIG_ALL_LTC3882 OPERATION MFR_RESET PWM Configuration FREQUENCY_SWITCH MFR_PWM_CONFIG_LTC3882 MFR_CHAN_CONFIG_LTC3882 MFR_PWM_MODE_LTC3882 Input Voltage and Limits VIN_ON VIN_OFF VIN_OV_FAULT_LIMIT VIN_UV_WARN_LIMIT Output Voltage and Limits VOUT_MODE VOUT_COMMAND MFR_VOUT_MAX VOUT_MAX MFR_VOUT_AVP VOUT_MARGIN_HIGH VOUT_MARGIN_LOW VOUT_OV_FAULT_LIMIT VOUT_OV_WARN_LIMIT VOUT_UV_WARN_LIMIT VOUT_UV_FAULT_LIMIT Output Current and Limits IOUT_CAL_GAIN MFR_IOUT_CAL_GAIN_TC IOUT_OC_FAULT_LIMIT IOUT_OC_WARN_LIMIT Output Timing, Delays, and Ramping MFR_RESTART_DELAY TON_DELAY TON_RISE TON_MAX_FAULT_LIMIT VOUT_TRANSITION_RATE TOFF_DELAY TOFF_FALL TOFF_MAX_WARN_LIMIT External Temperature and Limits MFR_TEMP_1_GAIN MFR_TEMP_1_OFFSET OT_FAULT_LIMIT OT_WARN_LIMIT Status Reporting STATUS_BYTE UT_FAULT_LIMIT STATUS_WORD STATUS_VOUT STATUS_IOUT STATUS_INPUT STATUS_TEMPERATURE STATUS_CML STATUS_MFR_SPECIFIC MFR_PADS_LTC3882 MFR_COMMON MFR_INFO CLEAR_FAULTS Telemetry READ_VIN MFR_VIN_PEAK READ_VOUT MFR_VOUT_PEAK READ_IOUT MFR_IOUT_PEAK READ_POUT READ_TEMPERATURE_1 MFR_TEMPERATURE_1_PEAK READ_TEMPERATURE_2 MFR_TEMPERATURE_2_PEAK READ_DUTY_CYCLE READ_FREQUENCY MFR_CLEAR_PEAKS Fault Response and Communication VIN_OV_FAULT_RESPONSE VOUT_OV_FAULT_RESPONSE VOUT_UV_FAULT_RESPONSE IOUT_OC_FAULT_RESPONSE OT_FAULT_RESPONSE UT_FAULT_RESPONSE MFR_OT_FAULT_RESPONSE TON_MAX_FAULT_RESPONSE MFR_RETRY_DELAY SMBALERT_MASK MFR_GPIO_PROPAGATE_LTC3882 MFR_GPIO_RESPONSE MFR_FAULT_LOG Fault Log Operation MFR_FAULT_LOG_CLEAR EEPROM User Access STORE_USER_ALL RESTORE_USER_ALL MFR_COMPARE_USER_ALL MFR_FAULT_LOG_STORE MFR_EE_xxxx USER_DATA_0x Unit Identification MFR_ID MFR_MODEL MFR_SERIAL MFR_SPECIAL_ID Typical Applications Package Description Revision History Typical Application Related Parts