Datasheet LTC3880, LTC3880-1 (Analog Devices)

LTC3880/LTC3880-1 Dual Output PolyPhase Step-Down DC/DC Controller with Digital Power System Management
FEATURES DESCRIPTION
n
PMBus/I2C Compliant Serial Interface
The LTC®3880/LTC3880-1 are dual, PolyPhase DC/DC n
Telemetry Read Back includes VIN, IIN, VOUT, IOUT,
synchronous step-down switching regulator controllers
Temperature and Faults
with an I2C-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 VIN Range: 4.5V to 24V The LTC3880 incorporates a 5V linear regulator while the n VOUT Range: 0.5V to 5.4V (4V on VOUT0) 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
VOUT Max Fast ADC Mode
n Available in a 40-Pin (6mm × 6mm) QFN Package
Start-Up Time VOUT0/1 for 1 Parameter
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
VIN 10µF 1µF
Efficiency and Power Loss
VIN INTVCC
vs Load Current
TG0 TG1 0.1µF 0.1µF LTC3880 100 6 VIN = 12V V 1.0µH BOOST0 BOOST1 0.56µH V 90 OUT0 OUT1 VOUT = 1.8V 3.3V SW0 SW1 1.8V 5 80 15A 2.15k BG0 BG1 1.74k 20A POWER LOSS (W) 70 0.2µF 0.2µF 4 PGND 60 I + + SENSEO ISENSE1 + 50 3 I – – SENSEO ISENSE1 530µF V + 40 SENSEO VSENSE1 V – EFFICIENCY (%) 2 SENSEO 30 TSNS0 TSNS1 + 10nF 10nF 20 1 2200pF 2200pF 530µF 6.04k 4.99k 10 ITHO ITH1 0 0 SDA GPIO0 0.01 0.1 1 10 100 FAULT MANAGEMENT SOME DETAILS OMITTED LOAD CURRENT (A) PMBus SCL GPIO1 FOR CLARITY INTERFACE ALERT 3880 TA01b RUN0 VDD33 RUN1 VDD25 TO/FROM SHARE_CLK 1µF 1µF OTHER LTC DEVICES SYNC SGND WRITE PROTECT WP 3880 TA01a Rev. H Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Table of Contents Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Overview Main Control Loop EEPROM Power Up and Initialization Soft-Start Sequencing Voltage-Based Sequencing Shutdown Light Load Current Operation Switching Frequency and Phase Output Voltage Sensing Current Sensing Load Sharing External/Internal Temperature Sense RCONFIG (Resistor Configuration) Pins Fault Detection and Handling Internal Memory with CRC and ECC Serial Interface Communication Failure Device Addressing Responses to VOUT and IOUT Faults Output Overvoltage Fault Response Output Undervoltage Response Peak Output Overcurrent Fault Response Responses to Timing Faults Responses to VIN OV Faults Responses to OT/UT Faults Overtemperature Fault Response—Internal Overtemperature and Undertemperature Fault Response—Externals Responses to External Faults Bus Timeout Failure Similarity Between PMBus, SMBus and I2C 2-Wire Interface PMBus Serial Digital Interface PMBus Command Summary PMBus Commands *Data Format Applications Information Current Limit Programming ISENSE+ and ISENSE– Pins Low Value Resistor Current Sensing Inductor DCR Current Sensing Slope Compensation and Inductor Peak Current Inductor Value Calculation Inductor Core Selection Power MOSFET and Schottky Diode (Optional) Selection Variable Delay Time, Soft-Start and Output Voltage Ramping Digital Servo Mode Soft Off (Sequenced Off) INTVCC Regulator Topside MOSFET Driver Supply (CB, DB) Undervoltage Lockout CIN and COUT Selection Fault Conditions Open-Drain Pins Phase-Locked Loop and Frequency Synchronization Minimum On-Time Considerations RCONFIG (External Resistor Configuration Pins) Voltage Selection Frequency and Phase Selection Using RCONFIG Address Selection Using RCONFIG Efficiency Considerations Checking Transient Response PC Board Layout Checklist PC Board Layout Debugging Design Example Connecting the USB to the I2C/SMBus/PMBus Controller to the LTC3880 In System LTpowerPlay: An Interactive GUI for Digital Power PMBus Communication and Command Processing PMBus Command Details Addressing and Write Protect General Configuration Registers On/Off/Margin PWM Config Voltage Input Voltage and Limits Output Voltage and Limits Current Input Current Calibration Output Current Calibration Input Current Output Current Temperature External Temperature Calibration External Temperature Limits Timing Timing—On Sequence/Ramp Timing—Off Sequence/Ramp Precondition for Restart Fault Response Fault Responses All Faults Fault Responses Input Voltage Fault Responses Output Voltage Fault Responses Output Current Fault Responses IC Temperature Fault Responses External Temperature Fault Sharing Fault Sharing Propagation Fault Sharing Response Scratchpad Identification Fault Warning and Status Telemetry NVM Memory Commands Store/Restore Fault Log Operation Fault Logging Block Memory Write/Read Typical Applications Package Description Revision History Typical Application Related Parts