Instruction Manual

MAX15303 PMBus Command Set User’s Guide
Page 10 of 52
VOUT_TRIM
VOUT_CAL_OFFSET, and the result is sent to the control loop as the output voltage setpoint.
Note that in the MAX15303, VOUT_TRIM is sent as a PMBus Linear value, rather than as a two’s
complement binary integer mantissa as specified in the PMBus standard, to avoid introducing
another numeric format.
The value of VOUT_TRIM is not subtracted from READ_VOUT, so non-zero VOUT_TRIM values will
result in a difference between VOUT_COMMAND and READ_VOUT.
This command is intended to allow an end user of a PMBus device to tailor a specific supply to the
performan
ce requirements of a specific load device, while retaining use of a “nominal” voltage
setpoint for all similar load devices.
VOUT_CAL_OFFSET
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x23
Format:
Linear
Data Bytes:
2
Units:
V
Transfer:
Read/Write Word
Factory Value:
0x0000 (0V)
Description/Notes:
See Section 13.4 of the PMBus Specification Part II.
In the MAX15303, the value of VOUT_CAL_OFFSET is summed with the value of VOUT_COMMAND
and VOUT_TRIM, and the result is sent to the control loop as the output voltage setpoint.
Note that in the MAX15303, VOUT_CAL_OFFSET is sent as a PMBus Linear value, rather than as a
two’s complement binary integer mantissa as specified in the PMBus standard, to avoid introducing
another numeric format.
The value of VOUT_CAL_OFFSET is subtracted from READ_VOUT, so VOUT_CAL_OFFSET values never
result in a difference between VOUT_COMMAND and READ_VOUT.
This command is intended to allow a PMBus device manufacturer or an end user to calibrate the
output voltage of a module (or other power-supply assembly)
to match an external reference
instrument during their final-test process.
VOUT_MAX
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x24
Format:
Unsigned integer mantissa
Data Bytes:
2
Units:
V
Transfer:
Read/Write Word
Factory Value:
0x5001 (5.000V)
Description/Notes:
See Section 13.5 of the PMBus Specification Part II.
VOUT_MAX mantissa data sent to and from the MAX15303 must be divided by 4096 to determine the
actual voltage value, according to the fixed value of VOUT_MODE
.
The factory value of 0x5001 (5.000V) will be overridden dur
ing initialization to
VOUT_COMMAND x 1.15, unless a specific value has been written to the User Store.