EVAL-ADM1276EBZ Analog Devices, EVAL-ADM1276EBZ Datasheet - Page 32

• Manufacturer Part Number: EVAL-ADM1276EBZ
• Description: Power Management IC Development Tools EVALUATION BOARD
• Manufacturer: Analog Devices
• Type: Hot Swap & Power Distributionr
• Series: ADM1276r

Specifications of EVAL-ADM1276EBZ

• Rohs: yes
• Tool Is For Evaluation Of: ADM1276
• Input Voltage: 20 V
• Factory Pack Quantity: 1

ADM1276
VOLTAGE AND CURRENT CONVERSION USING
LSB VALUES
The direct format voltage and current values returned by the
READ_VIN, READ_VOUT, and READ_IOUT commands, and
the corresponding peak versions, are the data output directly by
the ADM1276 ADC. Because the voltages and currents are 12-bit
ADC output codes, they can also be converted to real-world values
when there is knowledge of the size of the LSB on the ADC.
The m, b, and R coefficients defined for the PMBus conversion
are required to be whole integers by the standard and have,
therefore, been rounded slightly. Using this alternative method,
with the exact LSB values, can provide somewhat more accurate
numerical conversions.
To convert an ADC code to current in amperes, the following
formulas can be used:
where:
V
LSB
I
I
R
To convert an ADC code to a voltage, the following formula can
be used:
ADC
OUT
SENSE
SENSE
25 mV
is the 12-bit ADC code.
is the measured current value in amperes.
V
I
V
OUT
is the value of the sense resistor in milliohms.
= (V
SENSE
M
= LSB
= 12.4 µV.
= V
SENSE+
= LSB
SENSE
xV
) − (V
× (V
/(R
25 mV
SENSE
ADC
× (I
SENSE−
+ 0.5)
× 0.001)
ADC
).
− 2048)
Rev. B | Page 32 of 48
where:
V
V
LSB
Table 8. Voltage Ranges and LSB Values
Voltage Range, LSB
0 V to 6 V
0 V to 20 V
To convert a current in amperes to a 12-bit value, the following
formula can be used (round the result to the nearest integer):
where:
V
I
R
I
LSB
To convert a voltage to a 12-bit value, the following formula can
be used (round the result to the nearest integer):
where:
V
V
LSB
A
CODE
SENSE
M
ADC
SENSE
CODE
A
is the current value in amperes.
is the voltage value in volts.
is the measured value in volts.
xV
25 mV
xV
V
I
V
is the 12-bit ADC code.
is the 12-bit ADC code.
CODE
is the 12-bit ADC code.
values are based on the voltage range (see Table 8).
is the value of the sense resistor in milliohms.
values are based on the voltage range (see Table 8).
= (V
SENSE
CODE
= 12.4 µV.
= 2048 + (V
= (V
SENSE+
= I
A
A
× R
) − (V
/LSB
SENSE
xV
xV
SENSE
SENSE−
) − 0.5
× 0.001
/LSB
).
25 mV
)
LSB Magnitude
1.488 mV
5.208 mV
Data Sheet