POWER LOSS (W) LTC3889 60V Dual Output Step-Down Controller with Digital Power System Management FEATURES DESCRIPTION 2 n PMBus/I C Compliant Serial Interface The LTC 3889 is a dual PolyPhase DC/DC synchronous 2 Telemetry Read-Back Includes V , I , V , I , step-down switching regulator controller with I C-based IN IN OUT OUT 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 EXTV pin supports voltages up to 14V allowing for CC 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 V Range: 5V to 60V IN programmed both by digital interface as well as external n V , V Range: 1V to 40V OUT0 OUT1 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) The LTC3889 can be configured for discontinuous (pulse- n Available in a 52-Lead (7mm 8mm) QFN Package skipping) mode or continuous inductor current mode. All registered trademarks and trademarks are the property of their respective owners. Protected APPLICATIONS 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 V GATE OUT V RANGE RANGE DRIVE LTC3870 T IN ON MIN 0.1F 2 2m V (V) (V) (V) COMPATIBLE (ns) IN 30V TO 54V 10F LTC3889 5 to 60 1 to 40 6.3 to 9 No 45 10F 1F x4 + DRV V I I CC IN IN IN LTC3886 4.5 to 60 0.5 to 13.8 5 Yes 90 x2 x2 TG0 TG1 0.1F 0.1F BOOST0 BOOST1 Efficiency and Power Loss 8.6H 6.8H 2m 2m Efciency and Power Loss SW0 SW1 vs Load Current vs Load Current x2 x2 BG0 BG1 98 8 LTC3889* SDA FAULT0 SCL FAULT1 FAULT PMBus 96 7 ALERT PGOOD0 MANAGEMENT INTERFACE RUN0 PGOOD1 TO/FROM RUN1 SHARE CLK OTHER ADI DEVICES 94 6 + + I I SENSE0 SENSE1 30 1000pF 1000pF 30 92 5 I I SENSE0 SENSE1 V = 48V IN 30 30 V V EXTV OUT0 CC OUT1 V = 12V + OUT 24V V V 12V SENSE0 SENSE1 90 4 DRVSET = 2 20A V 20A SENSE0 EXTV = 12V 22F TSNS0 TSNS1 CC 22F + x4 I I + TH0 TH1 88 fsw = 150kHz 3 x4 150F 150F I I THR0 THR1 EFFICIENCY x2 x2 10nF 10nF V GND V 4700pF DD33 DD25 4700pF POWER LOSS 86 2 0 4 8 12 16 20 100pF 1F 1F 100pF LOAD CURRENT (A) 3889 TA01b *SOME DETAILS OMITTED FOR CLARITY 3889 TA01a Rev. A 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC3889 TABLE OF CONTENTS Features ..................................................... 1 Responses to V and I Faults/WARNINGS ....27 OUT OUT Applications ................................................ 1 Output Overvoltage Fault Response ...................27 Typical Application ........................................ 1 Output Undervoltage Response .........................27 Description.................................................. 1 Peak Output Overcurrent Fault Response ...........28 Table of Contents .......................................... 2 Responses to Timing Faults ....................................28 Absolute Maximum Ratings .............................. 4 Responses to V OV Faults ....................................28 IN Order Information .......................................... 4 Responses to OT/UT Faults .....................................28 Pin Configuration .......................................... 4 Internal Overtemperature Fault/Warn Response 28 Electrical Characteristics ................................. 5 External Overtemperature and Undertemperature Typical Performance Characteristics .................. 10 Fault Response ..................................................29 Pin Functions .............................................. 13 Responses to External Faults .................................29 Block Diagram ............................................. 15 Fault Logging ..........................................................29 Operation................................................... 16 Bus Timeout Protection ..........................................29 2 Overview ................................................................. 16 Similarity Between PMBus, SMBus and I C Main Control Loop .................................................. 16 2-Wire Interface ......................................................30 EEPROM ................................................................. 17 PMBus Serial Digital Interface ................................30 CRC Protection .................................................. 17 PMBus Command Summary ............................ 35 Power-Up and Initialization ..................................... 18 PMBus Commands .................................................35 Soft-Start ................................................................ 18 Applications Information ................................ 40 Time-Based Sequencing ......................................... 19 Current Limit Programming ....................................40 + Event-Based Sequencing ........................................ 19 I and I Pins .........................................40 SENSE SENSE Shutdown ............................................................... 19 Low Value Resistor Current Sensing ....................... 41 Light-Load Current Operation .................................20 Inductor DCR Current Sensing ................................42 PWM Loop Compensation ......................................20 Slope Compensation and Inductor Peak Current ....43 Switching Frequency and Phase .............................20 Inductor Value Calculation ......................................43 Output Voltage Sensing ..........................................21 Inductor Core Selection ..........................................44 Output Current Sensing ..........................................21 Power MOSFET and Optional Schottky Diode Input Current Sensing .............................................21 Selection .................................................................44 PolyPhase Load Sharing .........................................22 C and C Selection ...........................................45 IN OUT External/Internal Temperature Sense ......................22 Variable Delay Time, Soft-Start and Output Voltage RCONFIG (Resistor Configuration) Pins ..................23 Ramping .................................................................45 Fault Handling .........................................................23 Digital Servo Mode .................................................46 Status Registers and ALERT Masking ................. 24 Soft Off (Sequenced Off) ........................................ 47 Mapping Faults to FAULT Pins ............................26 DRV Regulator ....................................................48 CC Power Good Pins ................................................26 Topside MOSFET Driver Supply (C , D ) ................48 B B Serial Interface .......................................................26 Undervoltage Lockout .............................................49 Communication Protection ................................26 Fault Indications .....................................................49 Device Addressing ..................................................26 Open-Drain Pins .....................................................50 Rev. A 2 For more information www.analog.com