Datasheet

ADM1075
Data Sheet
Rev. B | Page 2 of 52
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Product Highlights ........................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 3
General Description ......................................................................... 4
Specifications ..................................................................................... 5
Serial Bus Timing ......................................................................... 9
Absolute Maximum Ratings .......................................................... 10
Thermal Resistance .................................................................... 10
ESD Caution ................................................................................ 10
Pin Configuration and Function Description ............................ 11
Typical Performance Characteristic ............................................. 13
Theory of Operation ...................................................................... 20
Powering the ADM1075 ............................................................ 20
Current Sense Inputs .................................................................. 21
Current Limit Reference ............................................................ 21
Setting the Current Limit (ISET).............................................. 22
Soft Start ...................................................................................... 22
Constant Power Foldback (PLIM) ........................................... 22
TIMER ......................................................................................... 23
Hot Swap Fault Retry ................................................................. 24
Fast Response to Severe Overcurrent ...................................... 24
UV and OV ................................................................................. 24
PWRGD
....................................................................................... 25
DRAIN ......................................................................................... 25
SPLYGD
....................................................................................... 25
LATCH
......................................................................................... 25
SHDN
........................................................................................... 25
RESTART
..................................................................................... 25
FET Health .................................................................................. 26
Power Monitor ............................................................................ 26
Isolation ....................................................................................... 26
PMBus Interface ............................................................................. 28
Device Addressing ...................................................................... 28
SMBus Protocol Usage ............................................................... 28
Packet Error Checking ............................................................... 28
Partial Transactions on I
2
C Bus ................................................ 28
SMBus Message Formats ........................................................... 29
Group Commands ...................................................................... 30
Hot Swap Control Commands ................................................. 31
ADM1075 Information Commands ........................................ 31
Status Commands ...................................................................... 31
GPO and Alert Pin Setup Commands..................................... 32
Power Monitor Commands ...................................................... 32
Warning Limit Setup Commands ............................................ 33
PMBus Direct Format Conversion .......................................... 34
Voltage and Current Conversion Using LSB Values .............. 35
ADM1075 Alert Pin Behavior ...................................................... 36
Faults and Warnings .................................................................. 36
Generating an Alert ................................................................... 36
Handling/Clearing an Alert ...................................................... 36
SMBus Alert Response Address ............................................... 37
Example Use of SMBus Alert Response Address ................... 37
Digital Comparator Mode ......................................................... 37
PMBus Command Reference........................................................ 38
Register Details ............................................................................... 39
Operation Command Register ................................................. 39
Clear Faults Register .................................................................. 39
PMBus Capability Register ....................................................... 39
IOUT OC Warn Limit Register ................................................ 39
VIN OV Warn Limit Register ................................................... 39
VIN UV Warn Limit Register ................................................... 39
PIN OP Warn Limit Register .................................................... 40
Status Byte Register .................................................................... 40
Status Word Register .................................................................. 40
IOUT Status Register ................................................................. 41
Input Status Register .................................................................. 41
Manufacturing Specific Status Register ................................... 42
Read EIN Register ...................................................................... 43
Read VIN Register...................................................................... 43
Read IOUT Register ................................................................... 43
Read PIN Register ...................................................................... 43
PMBus Revision Register .......................................................... 43
Manufacturing ID Register ....................................................... 44
Manufacturing Model Register ................................................ 44
Manufacturing Revision Register ............................................. 44
Peak IOUT Register ................................................................... 44
Peak VIN Register ...................................................................... 45
Peak VAUX Register .................................................................. 45