AD8417 查看數據表（PDF） - Analog Devices
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AD8417 Datasheet PDF : 16 Pages
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AD8417
THEORY OF OPERATION
The AD8417 is a single-supply, zero drift, difference amplifier
that uses a unique architecture to accurately amplify small
differential current shunt voltages in the presence of rapidly
changing common-mode voltages.
In typical applications, the AD8417 measures current by
amplifying the voltage across a shunt resistor connected to its
inputs by a gain of 60 V/V (see Figure 26).
The AD8417 design provides excellent common-mode rejection,
even with PWM common-mode inputs that can change at very
fast rates, for example, 1 V/ns. The AD8417 contains patented
technology to eliminate the negative effects of such fast
changing external common-mode variations.
The AD8417 features an input offset drift of less than 0.4 µV/°C.
This performance is achieved through a novel zero drift
Data Sheet
architecture that does not compromise bandwidth, which is
typically rated at 250 kHz.
The reference inputs, VREF1 and VREF2, are tied through 100 kΩ
resistors to the positive input of the main amplifier, which allows
the output offset to be adjusted anywhere in the output operating
range. The gain is 1 V/V from the reference pins to the output
when the reference pins are used in parallel. When the pins are
used to divide the supply, the gain is 0.5 V/V.
The AD8417 offers breakthrough performance without
compromising any of the robust application needs typical of
solenoid or motor control. The ability to reject PWM input
common-mode voltages and the zero drift architecture
providing low offset and offset drift allows the AD8417 to
deliver total accuracy for these demanding applications.
70V
VCM
0V
50A
ISHUNT
–50A
VCM = –2V TO +70V
+IN
ISHUNT
RSHUNT
–IN
EMI
FILTER
EMI
FILTER
VS = 2.7V TO 5.5V
VS
VREF1
+
G = 60
–
AD8417
OUT
VS
VS/2
0V
GND
VREF2
Figure 26. Typical Application
VOUT
Rev. 0 | Page 10 of 16
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