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Calibration commands, Iout_cal_gain, Iout_cal_offset – Maxim Integrated MAX15301 PMBus Command Set User Manual

Page 34: Ext_temp_cal (max15301aa01), Ext_temp_cal

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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.