AD8230YRZ-REEL 查看數據表（PDF） - Analog Devices
零件编号
产品描述 (功能)
生产厂家
AD8230YRZ-REEL Datasheet PDF : 16 Pages
| |||
AD8230
LAYOUT
The AD8230 has two reference pins: VREF1 and VREF2. VREF1
draws current to set the internal voltage references. In contrast,
VREF2 does not draw current. It sets the common mode of the
output signal. As such, VREF1 and VREF2 should be star-connected to
ground (or to a reference voltage). In addition, to maximize
CMR, the trace between VREF2 and the gain resistor, RG, should
be kept short.
APPLICATIONS
The AD8230 can be used in thermocouple applications, as
shown in Figure 3 and Figure 39. Figure 39 is an example of
such a circuit for use in an industrial environment. Series
resistors and low leakage diodes serve to clamp overload
voltages (see the Input Protection section for more information).
BAV199
+VS –VS
+VS
–VS
TYPE J
THERMOCOUPLE
+VS
100MΩ
4.99kΩ
4.99kΩ
100MΩ
–VS
0.1µF
0.1µF
2
4
1
1µF AD8230 8
5
6
3
7
19.1kΩ
200Ω
VOUT
+VS –VS
BAV199
Figure 39. Type J Thermocouple with Overvoltage Protection and RFI Filter
An antialiasing filter reduces unwanted high frequency signals.
The matched 100 MΩ resistors serve to provide input bias
current to the input transistors and serve as an indicator as to
when the thermocouple connection is broken. Well-matched
1% 4.99 kΩ resistors are used to form the antialiasing filter. It is
good practice to match the source impedances to ensure high
CMR. The circuit is configured for a gain of 193, which
provides an overall temperature sensitivity of 10 mV/°C.
+VS
–VS
0.1µF
+VS
0.1µF
350Ω
350Ω
350Ω
350Ω
2
4
1
AD8230
4kΩ
8
5
6
3
7
102kΩ
VOUT
1µF
1kΩ
–VS
Figure 40. Bridge Measurement with Filtered Output
Measuring load cells in industrial environments can be a
challenge. Often, the load cell is located some distance away
from the instrumentation amplifier. The common-mode
potential can be several volts, exceeding the common-mode
input range of many 5 V auto-zero instrumentation amplifiers.
Fortunately, the wide common-mode input voltage range of the
AD8230 spans 16 V, relieving designers of having to worry
about the common-mode range.
Rev. B | Page 14 of 16
Share Link: 