Manual

MAX15301 PMBus Command Set User’s Guide
Rev 1 Page 34 of 53
Calibration Commands
IOUT_CAL_GAIN
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x38
Format:
Linear
Data Bytes:
2
Units:
mΩ
Transfer:
Read/Write Word
Factory Value:
0xB200 (see Description)
Description/Notes:
See Section 14.8 of the PMBus Specification Part II.
The differential voltage measured between the DCRP and DCRN pins is divided by the value of
IOUT_CAL_GAIN and the value of IOUT_CAL_OFFSET
is subtracted to provide a load current signal,
accessible through the READ_IOUT command.
The factory value of 0xB200 (0.5mΩ) will be overridden during initialization by the hardware (pin-
strap) value determined by the resistances to ground detected at the ADDR1 pin, unless a specific
value of IOUT_CAL_GAIN has been written to the User Store. The value of the ADDR1 pin resistance is
measured only once during initialization (power-up).
The value of IOUT_CAL_GAIN is internally temperature compensated according to
READ_TEMPERATURE_2 and EXT_TEMP_CAL.
Wait at least 500μs for execution after sending the IOUT_CAL_GAIN command before sending
additional PMBus commands.
IOUT_CAL_OFFSET
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x39
Format:
Linear
Data Bytes:
2
Units:
A
Transfer:
Read/Write Word
Factory Value:
0x0000 (0A)
Description/Notes:
See Section 14.9 of the PMBus Specification Part II.
The differential voltage measured between the DCRP and DCRN pins is divided by the value of
IOUT_CAL_GAIN
and the value of IOUT_CAL_OFFSET is subtracted to provide a load current signal,
accessible through the READ_IOUT command.
Note that the MAX15301 implementation of IOUT_CAL_OFFSET differs from the PMBus specification
because the sign of IOUT_CAL_OFFSET is inverted (i.e., IOUT_CAL_OFFSET is subtracted rather than
added.)
EXT_TEMP_CAL (MAX15301AA01)
Reference:
Maxim Specific
Lockable:
Yes
Command Code:
0xF8
Format:
Linear
Data Bytes:
4
Units:
Scalar, °K
Transfer:
Read/Write Block
Factory Value:
0xBA02 (1.004363), 0x0000 (0°K)
Description/Notes:
The EXT_TEMP_CAL command allows the user to calibrate the READ_TEMPERATURE_2 data and to
adjust for different temperature-sense diode junction ideality factors.