Datasheet LTC3886, LTC3886-1 (Analog Devices)

LTC3886/LTC3886-1 60V Dual Output Step-Down Controller with Digital Power System Management
FEATURES DESCRIPTION
n
PMBus/I2C Compliant Serial Interface
The LTC®3886/LTC3886-1 is a dual PolyPhase DC/DC syn- n
Telemetry Read-Back Includes VIN, IIN, VOUT, IOUT,
chronous step-down switching regulator controller with
Temperature and Faults
I2C-based PMBus compliant serial interface. This controller n
Programmable Voltage, Current Limit, Digital
employs a constant-frequency, current-mode architecture,
Soft-Start/Stop, Sequencing, Margining, OV/UV/OC,
with high voltage input and output capability along with
Frequency, and Control Loop Compensation
programmable loop compensation. The LTC3886 is sup- n
Output Error Less Than ±0.5% Over Temperature
ported by the LTpowerPlay® software development tool with n
Integrated 16-Bit ADC and 12-Bit DAC
graphical user interface (GUI). n
Integrated High Side Current Sense Amplifier
The EXTVCC pin supports voltages up to 14V allowing for n
Internal EEPROM with ECC and Fault Logging
optimized circuit efficiency and die temperature, and for n
Integrated N-Channel MOSFET Gate Drivers
the controller output to supply the chip power. Switching
Power Conversion
frequency, output voltage, and device address can be n Wide VIN Range: 4.5V to 60V programmed both by digital interface as well as external n VOUT0, VOUT1 Range: 0.5V to 13.8V configuration resistors. Parameters can be set via the n Analog Current Mode Control digital interface or stored in EEPROM. Both outputs have n Accurate PolyPhase® Current Sharing for an independent power good indicator and FAULT function. Up to 6 Phases (100kHz to 750kHz) The LTC3886 can be configured for discontinuous (pulse- n Available in a 52-Lead (7mm × 8mm) QFN Package skipping) mode or continuous inductor current mode. The LTC3886-1 also includes a sequencing off feature to
APPLICATIONS
discharge very large output capacitors. n Telecom, Datacom, and Storage Systems All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 5408150, n Industrial and Point of Load Applications 6580258, 6304066, 7420359, 8786268 Patent Pending. Licensed under U.S. Patent 7000125 and other related patents worldwide.
TYPICAL APPLICATION
10µF 2Ω 5mΩ VIN 18V TO 48V 10µF 1µF INTV + – CC VIN IIN IIN TG0 TG1
Efficiency and Power Loss
0.1µF 0.1µF
vs Load Current
BOOST0 BOOST1 3.1µH 6.82µH 100 9 SW0 SW1 VIN = 48V 90 V BG0 BG1 OUT = 12V 8 6.81k LTC3886* 7.5k 80 fSW = 150kHz SDA FAULT0 7 1µF SCL FAULT1 1µF POWER LOSS (W) 70 PMBus FAULT MANAGEMENT 6 ALERT PGOOD0 INTERFACE 60 RUN0 PGOOD1 TO/FROM 5 RUN1 SHARE_CLK OTHER ADI DEVICES 50 + + 4 ISENSE0 ISENSE1 40 6.81k 0.22µF 0.22µF 7.5k – – EFFICIENCY (%) ISENSE0 ISENSE1 30 3 VOUT0 EXTVCC VOUT1 + 20 2 5V VSENSE0 VSENSE1 12V 15A V – SENSE0 15A 10 EFFICIENCY 1 TSNS0 TSNS1 POWER LOSS + ITH0 ITH1 + 0 0 530µF I I 530µF 0.01 0.1 1 10 100 THR0 THR1 10nF VDD33 GND V 10nF LOAD CURRENT (A) 4700pF DD25 2200pF 3883 TA01b 220pF 1µF 1µF 220pF *SOME DETAILS OMITTED FOR CLARITY 3886 TA01a Rev F Document Feedback For more information www.analog.com 1 Document Outline Table of Contents Features Power Conversion Applications Typical Application Description Table of Contents Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Overview Main Control Loop EEPROM Power-Up and Initialization Soft-Start Time-Based Sequencing Event-Based Sequencing Shutdown Light-Load Current Operation PWM Loop Compensation Switching Frequency and Phase Output Voltage Sensing Output Current Sensing Input Current Sensing PolyPhase Load Sharing External/Internal Temperature Sense RCONFIG (Resistor Configuration) Pins Fault Handling Status Registers and ALERT Masking Mapping Faults to FAULT Pins Power Good Pins CRC Protection Serial Interface Communication Protection 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 Internal Overtemperature Fault/Warn Response External Overtemperature and Undertemperature Fault Response Responses to External Faults Fault Logging Bus Timeout Protection 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 Optional Schottky Diode Selection CIN and COUT 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 Fault Indications Open-Drain Pins Phase-Locked Loop and Frequency Synchronization Minimum On-Time Considerations External Temperature Sense Derating EEPROM Retention at Temperature Input Current Sense Amplifier External Resistor Configuration Pins (RCONFIG) Voltage Selection Frequency Selection Phase Selection Address Selection Using RCONFIG Efficiency Considerations Programmable Loop Compensation Checking Transient Response PolyPhase Configuration PC Board Layout Checklist PC Board Layout Debugging Design Example Additional Design Checks Connecting the USB to I2C/SMBus/PMBus Adapter to the LTC3886 In System LTpowerPlay: An Interactive GUI for Digital Power PMBus Communication and Command Processing PMBus Command Details Addressing and Write Protect General Configuration COMMANDS On/Off/Margin ON_OFF_CONFIG PWM Configuration Voltage Input Voltage and Limits Output Voltage and Limits For EnableMfrVoffThreshold = 0 For EnableMfrVoffThreshold = 1 Output Current and Limits Input Current and Limits Temperature External Temperature Calibration 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 EEPROM Memory Commands Store/Restore Fault Logging Fault Log Operation Block Memory Write/Read Typical Applications Package Description Revision History Typical Application Related Parts