IR3725MPBF International Rectifier, IR3725MPBF Datasheet - Page 14

• Manufacturer Part Number: IR3725MPBF
• Description: Input Power Monitor IC with Digital Interface
• Manufacturer: International Rectifier

Specifications of IR3725MPBF

• Package: 12 Lead DFN
• Bias Supply Voltage: +3.3V +/-5%
• Junction Temperature: 0oC to 125oC
• Pbf: Yes

OUTPUT REGISTER
The output register is loaded with a two’s compliment
factor of voltage, current, or power, depending on the
last request loaded into the configuration register.
Serial bus “Direct Data Format” is used. The value of
the output register is to be multiplied by a scale factor
that is derived below to yield power, voltage, or
current in engineering units of watts, volts, or amps.
Maximum power is the product of maximum voltage
and maximum current.
The range of valid output register values is indicated
in Table 2 below.
Table 2 Output Register Range of Returned
Values
Parameter
FS voltage
Zero voltage
+FS current
-FS current
+FS power
-FS power
A binary point is implicitly located to the left of the first
six least significant figures, as in the example below.
SYYY YYYY YY.00 0000
The “S” above is the twos compliment sign bit, and
the “Y’s” are the twos compliment integers. Six zeros
pad out the two byte response. These padding zeros
could be considered a factor of the slope, which is
allowed by the Direct Data Format. The output
register multiplied by its scale factor K
requested quantity in engineering units, volts, amps,
or watts.
The equations below convert digital counts to
engineering units:
Voltage = counts * V
Current = counts * V
(R
Power = counts * V
(R
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T
T
*DCR*256)
* DCR * 256)
Returned value
(twos compliment
binary)
0100 0000 0000 0000
0000 0000 0000 0000
0100 0000 0000 0000
1100 0000 0000 0000
0100 0000 0000 0000
1100 0000 0000 0000
FS
IG
FS
*V
* (R
/ 256
IG
*(Rcs1 + Rcs2) /
CS1
+R
CS2
) /
x
yields the
www.irf.com
Returned
value
(decimal)
256
0
256
-256
256
-256
There is but one output register, and it holds the
measurement type (voltage, current, or power) last
requested by the configuration register. It is
incumbent upon the user to establish correct
configuration before requesting a read.
READ_VOUT, READ_IOUT, and READ_POUT are
equivalent in that each returns the contents of the
same output register.
BIT#
d15:d0
RESERVED COMMAND
CODES
Command codes D2h through D5h, D7h, and D8h
are reserved for manufacturing use only and could
lead to undesirable device behavior.
OUTPUT REGISTER
Output variable, D0 is LSB
IR3725
Data Sheet
2011_11_16