Datasheet

LTC3883/LTC3883-1
2
3883fa
For more information www.linear.com/LTC3883
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 I
2
C
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