Datasheet LTC3888-1 (Analog Devices)

LTC3888-1 Dual Loop 8-Phase Step-Down DC/DC Controller with Digital Power System Management
FEATURES DESCRIPTION
n
PMBus/I2C Compliant Serial Interface
The LTC®3888-1 is a PMBus-compliant dual loop DC/DC n
Monitor Voltage, Current, Temperature and Faults
synchronous step-down switching regulator controller n
Digitally Program V
with eight expandable phases supporting a wide range of
OUT, Margins, UV, OV, Current Limit, Soft-Start/Stop and Sequencing
master/slave configurations. The controller uses constant n
Expandable to >16 Phases
frequency current mode architecture to provide excellent n
External Resistor Divider Programs Output Voltage
transient response and output regulation. Each PWM n
4.5V ≤ V
master is capable of producing output voltages from 0.3V
IN ≤ 26.5V, 0.3V ≤ VOUT ≤ 3.45V
n
±0.5% Output Voltage Accuracy
to 3.45V with multiple phase configurations using DrMOS n
Programmable PWM Loop Compensation
devices that provide an output current monitor. n
Accurate PolyPhase
®
Current Sharing
Output voltage is set with an external voltage divider. n
Internal EEPROM with ECC and Fault Logging
PMBus configuration and monitoring is supported by n DrMOS Output Current Monitor Interface LTpowerPlay™ software. Programmable loop compen- n DrMOS Temperature/Fault Bus Interface sation and built-in load step emulation facilitate setting n DrMOS Gate Drive Supply Monitor bandwidth based on input voltage and output load capaci- n Load Step Emulation tance. PMBus commands allow read back of input volt- n Internal or External PWM Clock from 250kHz to 1MHz age, output voltage and current, and operating status. n 52-Pin (5mm × 8mm) QFN Package Operating parameters can be set via PMBus command or n AEC-Q100 Qualified for Automotive Applications stored in internal EEPROM for use at power up. Switching frequency, phase configuration, output current limit and device address can also be set using external program-
APPLICATIONS
ming resistors. n High Current Distributed Power Systems All registered trademarks and trademarks are the property of their respective owners. Protected n Servers, Network and Storage Equipment by U.S. Patents, including 7420359, 8786265, 8786268 and 8823352. Licensed under U.S. Patent 7000125 and other related patents worldwide.
TYPICAL APPLICATION SPI VOUT SET BY PMBus OPTIONAL ADJUST ANALOG VFB CONTROL COMPENSATION OF V Dual 4-phase PSM Rails OUT OF VOUT ZERO
VIN 5V TO 24V LTC3888 • • (NOMINAL) 2.2µF 1µF 4.7µF LTC3888-1 • • • VIN INTVCC POWER STAGE POWER STAGE LTC3888-2 • • VOUT1 VIN PWM PWM1 PWM0 PWM V V IN OUT0 0.4V TO 0.4V TO 3.45V SW IMON ISENSE1 ISENSE0 IMON SW 3.45V
Efficiency vs Load Current Efficiency vs Load Current
AT 120A GND IREF IREF LTC3888-1 IREF GND AT 120A
(8–Phase Using LTC7051) (8-Phase Using LTC7051)
TEMP TSNS1 TSNS0 TEMP 100 VSENSE1+ VSENSE0+ VIN = 12V V V at 500kHz SENSE1– SENSE0– 95 DAOUT1 DAOUT0 VFB1 VFB0 90 SYNC PGOOD0 FAULT0 PGOOD1 PSM FAULT1 85 SHARED RUN0 SCL PINS RUN1 SDA PMBus EFFICIENCY (%) NOTE: SOME DETAILS OMITTED FOR CLARITY 80 SHARE_CLK ALERT ONLY TWO OF EIGHT CHANNELS SHOWN 0.6V ITHR1 ITHR0 0.8V 2200pF ITH1 ITH0 2200pF 75 1.0V 100pF VDD33 VDD25 100pF 1.8V 1µF GND 1µF 70 0 80 160 240 320 400 388812 TA01a LOAD CURRENT (A) 3888-1 G01 Rev. 0 Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Test Circuit Operation Overview About This Document Major Product Features Main Control Loop Power-Up and Initialization Testing Integrity of Output Voltage Sense Analog Output Voltage Control PMBus Output Voltage Control Soft-Start Time-Based Output Sequencing Output Ramping Control Voltage-Based Output Sequencing Output Disable Minimum Output Disable Times Output Short Cycle Switching Frequency and Phase PolyPhase Load Sharing Voltage Control Loop Compensation Load Step Emulation Input Supply Monitoring Output Voltage Sensing and Monitoring Output Current Sensing and Monitoring Temperature Sense Resistor Configuration Pins Internal EEPROM with CRC Fault Detection Input Supply Faults Hardwired PWM Response to Power Stage Faults Hardwired PWM Response to Power Stage UV Hardwired PWM Response to VOUT Faults Power Good Indication Hardwired PWM Response to IOUT Faults Hardwired PWM Response to Internal Temperature Faults External Temperature Faults Timing Faults External Faults Higher-Level Fault Handling Status Registers and ALERT Masking FAULT Pin I/O Fault Log Operation Fault Log Details 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 Power Stage Selection and Interface Using The VDR Monitor Unused TSNS Inputs PWM Frequency and Inductor Selection CIN Selection COUT Selection Programmable Loop Compensation PCB Layout Considerations Output Voltage Sensing Classical Analog Output Voltage Control PMBus Output Voltage Control Using Output Voltage Servo Soft-Start and Stop Time-Based Output Sequencing and Ramping Voltage-Based Output Sequencing PWM Frequency Synchronization PolyPhase Operation and Load Sharing 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 MFR_CONFIG_ALL On, Off and Margin Control ON_OFF_CONFIG OPERATION MFR_RESET PWM Configuration FREQUENCY_SWITCH MFR_CHAN_CONFIG MFR_PWM_CONFIG_LTC3888-1 MFR_PWM_MODE_LTC3888-1 MFR_PWM_COMP Input Voltage and Limits VIN_ON VIN_OFF VIN_OV_FAULT_LIMIT VIN_UV_WARN_LIMIT Output Voltage and Limits VOUT_MODE VOUT_COMMAND VOUT_MAX MFR_VOUT_MAX VOUT_MARGIN_HIGH VOUT_MARGIN_LOW VOUT_SCALE_LOOP VOUT_OV_FAULT_LIMIT VOUT_OV_WARN_LIMIT VOUT_UV_WARN_LIMIT VOUT_UV_FAULT_LIMIT Output Current and Limits IOUT_CAL_GAIN MFR_LOAD_EMULATION MFR_LOAD_EMULATION IOUT_OC_FAULT_LIMIT IOUT_OC_WARN_LIMIT Output Timing, Delays, and Ramping MFR_RESTART_DELAY TON_DELAY TON_MAX_FAULT_LIMIT VOUT_TRANSITION_RATE TOFF_DELAY 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 STATUS_WORD STATUS_VOUT STATUS_IOUT STATUS_INPUT STATUS_TEMPERATURE STATUS_CML STATUS_MFR_SPECIFIC MFR_PADS_LTC3888-1 MFR_COMMON MFR_INFO CLEAR_FAULTS Telemetry READ_VIN MFR_VIN_PEAK READ_VOUT MFR_VOUT_PEAK READ_IOUT MFR_IOUT_PEAK MFR_TOTAL_IOUT MFR_READ_ALL_IOUT READ_TEMPERATURE_1 MFR_TEMPERATURE_1_PEAK READ_TEMPERATURE_2 MFR_TEMPERATURE_2_PEAK 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 MFR_OT_FAULT_RESPONSE TON_MAX_FAULT_RESPONSE MFR_RETRY_DELAY SMBALERT_MASK MFR_FAULT_PROPAGATE MFR_FAULT_RESPONSE MFR_FAULT_LOG 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 IC_DEVICE_ID MFR_SPECIAL_ID Package Description Typical Applications Related Parts