IR3720MTRPBF International Rectifier, IR3720MTRPBF Datasheet - Page 13

• Manufacturer Part Number: IR3720MTRPBF
• Description: IC POWER SUPPLY MONITOR 10-DFN
• Manufacturer: International Rectifier
• Series: TruePower™r

Specifications of IR3720MTRPBF

• Package / Case: 10-DFN
• Mounting Type: Surface Mount
• Current - Supply: 480µA
• Voltage - Supply: 3.135 V ~ 3.465 V
• Operating Temperature: 0°C ~ 125°C
• Applications: Power Supply Monitor
• Voltage - Input: -
• Input Voltage: 3.3V
• No. Of Outputs: 1
• Supply Voltage Range: 3.135V To 3.465V
• No. Of Pins: 10
• Operating Temperature Range: 0°C To +125°C
• Filter Terminals: SMD
• Input Voltage Primary Max: 3.3V
• Rohs Compliant: Yes
• Frequency: 400kHz
• Package: 10 Lead 3x3 DFN
• Vk Range: 0.5V - 1.8V
• Bias Supply Voltage: +3.3V +/-5%
• Junction Temperature: 0oC to 125oC
• Pbf: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

ERROR MANAGEMENT
Component value errors external to the IR3720
contribute to power and current measurement error.
The power reported by the IR3720 is a function not
only of actual power or current, but also of products
and quotients of R
well as parameters internal to the IR3720. The
tolerance of these components increases the total
power or current error. Small signal resistors are
typically available in 1% tolerance, but 0.1% parts are
available. Shunts are also available at 1% or 0.1%
tolerance. The DCR tolerance of inductors can be
5%, but 3% are available. Fortunately, it is not typical
that worst-case errors would systematically stack in
one direction. It is statistically likely that a high going
value would be paired with a low going value to
somewhat cancel the error. Because of this,
tolerances can be added in quadrature (RSS). As an
example, a 3% DCR used with a 1% R
and 3.3% IR3720 contributes
error to a typical system.
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Quantization error occurs in digital systems because
the full scale is partitioned into a finite number of
intervals and the number of the interval containing
the measured value is reported. It is not likely that the
measured value would correspond exactly to the
center of the interval. The error could be as large as
half the width of the interval. With a binary word size
of eight, full scale is partitioned into 255 intervals.
Consider a measurement made near full scale. Any
signal in this interval is less than ± .2% (one-half of
100% / 256) away from the interval’s center, and
would therefore never have more error than that due
to quantization. On the other hand, consider a
measurement at one-tenth full scale. One-half of an
interval size at this level corresponds to 2% of the
reported value! Relative quantization error increases
as the measured value becomes small compared to
the full-scale value.
Quantization error can be reduced by averaging a
sequence of returned values.
09/09/08