Datasheet

LTC2974
27
2974fc
For more information www.linear.com/LTC2974
Summary Table
COMMAND NAME
CMD
CODE DESCRIPTION TYPE PAGED
DATA
FORMAT UNITS EEPROM
DEFAULT
VALUE:
FLOAT
HEX
REF
PAGE
MFR_COMMON 0xEF Manufacturer status bits that are common
across multiple LTC chips.
R Byte N Reg NA
61
MFR_IOUT_CAL_GAIN_TC 0xF6 Temperature coefficient applied to IOUT_
CAL_GAIN.
R/W Word Y CF ppm Y 0x0
46
MFR_RETRY_COUNT 0xF7 Retry count for all faulted off conditions
that enable retry.
R/W Byte N Reg Y 0x00
54
MFR_TEMP_1_GAIN 0xF8 Inverse of external diode temperature non
ideality factor. One LSB = 2
–14
.
R/W Word Y CF Y 1
0x4000
48
MFR_TEMP_1_OFFSET 0xF9 Offset value for the external temperature. R/W Word Y L11 °C Y 0
0x8000
48
MFR_IOUT_SENSE_VOLTAGE 0xFA Absolute value of V
ISENSEP
– V
ISENSEM
.
One LSB = 3.05µV.
R Word Y CF 3.05µV NA 66
MFR_VOUT_MIN 0xFB Minimum measured value of READ_VOUT. R Word Y L16 V NA
66
MFR_VIN_MIN 0xFC Minimum measured value of READ_VIN. R Word N L11 V NA
66
MFR_TEMPERATURE_1_MIN 0xFD Minimum measured value of READ_
TEMPERATURE_1.
R Word Y L11 °C NA
66
pMbus coMManD suMMary
Data Formats
L11 Linear_5s_11s PMBus data field b[15:0]
Value = Y • 2
N
where N = b[15:11] is a 5-bit two’s complement integer and Y = b[10:0] is an 11-bit two’s complement integer
Example:
READ_VIN = 10V
For b[15:0] = 0xD280 = 1101_0010_1000_0000b
Value = 640 • 2
–6
= 10
See PMBus Spec Part II: Paragraph 7.1
L16 Linear_16u PMBus data field b[15:0]
Value = Y • 2
N
where Y = b[15:0] is an unsigned integer and N = Vout_mode_parameter is a 5-bit two’s complement exponent
that is hardwired to –13 decimal.
Example:
VOUT_COMMAND = 4.75V
For b[15:0] = 0x9800 = 1001_1000_0000_0000b
Value = 38912 • 2
–13
= 4.75
See PMBus Spec Part II: Paragraph 8.3.1
Reg Register PMBus data field b[15:0] or b[7:0].
Bit field meaning is defined in detailed PMBus Command Register Description.
CF Custom Format PMBus data field b[15:0]
Value is defined in detailed PMBus Command Register Description. This is often an unsigned or two’s complement integer
scaled by an MFR specific constant.