LTC3883 Datasheet, PDF (2/112 Pages) Linear Technology – Single Phase Step-Down DC/DC Controller with Digital Power System Management

LTC3883/LTC3883-1
Table of Contents
Features...................................................... 1
Applications................................................. 1
Typical Application......................................... 1
Description.................................................. 1
Table of Contents........................................... 2
Absolute Maximum Ratings............................... 4
Pin Configuration........................................... 4
Order Information........................................... 4
Electrical Characteristics.................................. 5
Typical Performance Characteristics.................... 9
Pin Functions............................................... 12
Block Diagram.............................................. 14
Operation................................................... 15
Overview.................................................................. 15
Main Control Loop................................................... 15
EEPROM.................................................................. 16
Power Up and Initialization...................................... 16
Soft-Start................................................................. 17
Sequencing.............................................................. 17
Voltage-Based Sequencing...................................... 18
Shutdown................................................................ 18
Light Load Current Operation.................................. 19
Switching Frequency and Phase.............................. 19
Output Voltage Sensing........................................... 20
Output Current Sensing........................................... 20
Auto Calibration ...................................................... 20
Accurate DCR Temperature Compensation ............. 20
Input Current Sensing.............................................. 20
Load Sharing........................................................... 21
External/Internal Temperature Sense....................... 21
RCONFIG (Resistor Configuration) Pins...................22
Fault Detection and Handling...................................23
CRC Failure ......................................................... 24
Serial Interface........................................................ 24
Communication Failure ....................................... 24
Device Addressing................................................... 24
Responses to V_OUT and I_OUT Faults......................... 25
Output Overvoltage Fault Response....................25
Output Undervoltage Response .......................... 25
Peak Output Overcurrent Fault Response............ 25
Responses to Timing Faults.....................................26
Responses to V_IN OV Faults.....................................26
Responses to OT/UT Faults......................................26
Overtemperature Fault Response—Internal ....... 26
Overtemperature and Undertemperature
Fault Response—Externals ................................26
Responses To Input Overcurrent And Output
Undercurrent Faults................................................. 27
Responses to External Faults .................................. 27
Fault Logging........................................................... 27
Bus Timeout Failure................................................. 27
Similarity Between PMBus, SMBus and I²C
2-Wire Interface....................................................... 27
PMBus Serial Digital Interface................................. 28
PMBus Command Summary............................. 31
PMBus Commands.................................................. 31
*Data Format...........................................................36
Applications Information................................. 37
Current Limit Programming..................................... 37
I_SENSE+ and I_SENSE– Pins.......................................... 37
Low Value Resistor Current Sensing........................38
Inductor DCR Current Sensing.................................39
Slope Compensation and Inductor Peak Current.....40
Inductor Value Calculation.......................................40
Inductor Core Selection........................................... 41
Power MOSFET and Schottky Diode (Optional)
Selection.................................................................. 41
Variable Delay Time, Soft-Start and Output Voltage
Ramping.................................................................. 42
Digital Servo Mode..................................................43
Soft Off (Sequenced Off).........................................43
INTV_CC Regulator.....................................................44
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