Datasheet LTC3889 (Analog Devices)

LTC3889 60V Dual Output Step-Down Controller with Digital Power System Management
FEATURES DESCRIPTION
n
PMBus/I2C Compliant Serial Interface
The LTC®3889 is a dual PolyPhase DC/DC synchronous
– Telemetry Read-Back Includes VIN, IIN, VOUT, IOUT,
step-down switching regulator controller with I2C-based
Temperature and Faults
PMBus compliant serial interface. This controller employs
– Programmable Voltage, Current Limit, Digital
a constant-frequency, current-mode architecture, with high
Soft-Start/Stop, Sequencing, Margining, OV/UV/OC,
voltage input and output capability along with program-
Frequency, and Control Loop Compensation
mable loop compensation. The LTC3889 is supported by n
Output Error Less Than ±0.5% Over Temperature
the LTpowerPlay™ software development tool with graphical n
Integrated 16-Bit ADC and 12-Bit DAC
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: 5V to 60V programmed both by digital interface as well as external n VOUT0, VOUT1 Range: 1V to 40V 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 (85kHz to 500kHz) n The LTC3889 can be configured for discontinuous (pulse- Available in a 52-Lead (7mm × 8mm) QFN Package skipping) mode or continuous inductor current mode.
APPLICATIONS
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, 6580258, 6304066, 7420359, 8786268 Patent Pending. Licensed under U.S. Patent 7000125 n Telecom, Datacom, and Storage Systems and other related patents worldwide. n Industrial and Point of Load Applications
TYPICAL APPLICATION VOUT GATE
0.1µF 2Ω
V RANGE DRIVE LTC3870 T
2mΩ
IN RANGE ON_MIN
VIN 30V TO 54V
(V) (V) (V) COMPATIBLE (ns)
10µF 1µF LTC3889 5 to 60 1 to 40 6.3 to 9 No 45 DRV + – CC VIN IIN IIN TG0 TG1 LTC3886 4.5 to 60 0.5 to 13.8 5 Yes 90 0.1µF 0.1µF BOOST0 BOOST1 5mΩ 8.6µH 10µH 4mΩ
Efficiency and Power Loss
SW0 SW1
vs Load Current
BG0 BG1 LTC3889* 97 10 SDA FAULT0 SCL FAULT1 FAULT PMBus ALERT PGOOD0 MANAGEMENT INTERFACE 94 8 RUN0 PGOOD1 TO/FROM RUN1 SHARE_CLK POWER LOSS (W) OTHER ADI DEVICES I + + SENSE0 ISENSE1 91 6 30Ω 1000pF 1000pF 30Ω I – – SENSE0 ISENSE1 V 30Ω 30Ω OUT0 EXTV VOUT1 + CC 88 4 24V VSENSE0 VSENSE1 12V EFFICIENCY (%) 10A V – 15A V SENSE0 IN = 48V TSNS0 TSNS1 VOUT = 12V 85 + ITH0 ITH1 + f 2 SW = 150kHz 530µF ITHR0 ITHR1 530µF EFFICIENCY 10nF VDD33 GND V 10nF POWER LOSS 2200pF DD25 2200pF 82 0 220pF 1µF 1µF 220pF 0 4 8 12 16 20 LOAD CURRENT (A) 3889 TA01b *SOME DETAILS OMITTED FOR CLARITY 3889 TA01a Rev. 0 Document Feedback For more information www.analog.com 1 Document Outline Table of Contents Features 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 CRC Protection 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 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 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) DRVCC 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 LTC3889 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 PWM Configuration Voltage Input Voltage and Limits Output Voltage and Limits 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 Typical Application Related Parts