- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄372951 > XTR103AU 4-20mA Current Transmitter with RTD EXCITATION AND LINEARIZATION PDF資料下載
參數(shù)資料
| 型號： | XTR103AU |
| 英文描述： | 4-20mA Current Transmitter with RTD EXCITATION AND LINEARIZATION |
| 中文描述： | 4 - 20mA電流變送器的RTD激勵和線性化 |
| 文件頁數(shù)： | 6/10頁 |
| 文件大?。?/td> | 222K |
| 代理商： | XTR103AU |
6
XTR103
–
+
12
13
4
5
6
3
R
G
XTR103
R = 1.5k
7
I
=
0.8mA
0.01μF
I = 4mA + V
IN
(0.016 + 40
R
G
R
Z
RTD
9
8
R
LIN
(2, 3)
NOTES: (1) R
Z
= RTD resistance at the minimum measured temperature.
I
=
0.8mA
V
IN
R
G
R
G
V
–
IN
V
+
IN
I
R
I
R
V+
R
LIN
R
LIN
I
O
E
B
(1, 3)
R
G
= 1
V
FS
2500
– 1
(2)
V
PS
–
–
+
11
4-20 mA
0.01μF
+
15
10
V
= V
+
= I
R
(RTD – R
Z
)
– V
–
R
L
(3)
Q
1
, where V
FS
is Full Scale V
IN
.
(3)See Table I for values.
TYPE
2N4922
TIP29B
TIP31B
PACKAGE
TO-225
TO-220
TO-220
Possible choices for Q
1
(see text).
APPLICATION INFORMATION
Figure 1 shows the basic connection diagram for the XTR103.
The loop power supply, V
PS
provides power for all circuitry.
Output loop current is measured as a voltage across the
series load resistor, R
L
.
Two matched 0.8mA current sources drive the RTD and
zero-setting resistor, R
Z
. The instrumentation amplifier in-
put of the XTR103 measures the voltage difference between
the RTD and R
Z
. The value of R
Z
is chosen to be equal to
the resistance of the RTD at the low-scale (minimum)
measurement temperature. R
Z
can be adjusted to achieve
4mA output at the minimum measurement temperature to
correct for input offset voltage and reference current mis-
match of the XTR103.
R
CM
provides an additional voltage drop to bias the inputs of
the XTR103 within their common-mode range. Resistor, R
G
,
sets the gain of the instrumentation amplifier according to
the desired temperature measurement range.
The transfer function through the complete instrumentation
amplifier and voltage-to-current converter is:
I
O
= V
IN
(0.016 + 40/R
G
) + 4mA,
(V
IN
in volts, R
G
in ohms, R
LIN
=
∞
)
where V
IN
is the differential input voltage. With no R
G
connected (R
G
=
∞
), a 0V to 1V input produces a 4-20mA
output current. With R
G
= 25
, a 0V to 10mV input pro-
duces a 4-20mA output current. Other values for R
G
can be
calculated according to the desired full-scale input voltage,
V
FS
, with the formula in Figure 1.
Negative input voltage, V
IN
, will cause the output current to
be less than 4mA. Increasingly negative V
IN
will cause the
output current to limit at approximately 3.6mA.
Increasingly positive input voltage (greater than V
FS
) will
produce increasing output current according to the transfer
function, up to the output current limit of approximately
34mA.
EXTERNAL TRANSISTOR
Transistor Q
1
conducts the majority of the signal-dependent
4-20mA loop current. Using an external transistor isolates
the majority of the power dissipation from the precision
input and reference circuitry of the XTR103, maintaining
excellent accuracy.
Since the external transistor is inside a feedback loop its
characteristics are not critical. Requirements are: V
CEO
=
45V min,
β
= 40 min and P
D
= 800mW. Power dissipation
requirements may be lower if the loop power supply voltage
is less than 40V. Some possible choices for Q
1
are listed in
Figure 1.
The XTR103 can be operated without this external transistor
by connecting pin 11 to 14 (see Figure 2). Accuracy will be
somewhat degraded by the additional internal power dissipa-
tion. This effect is most pronounced when the input stage is
set for high gain (for low full-scale input voltage). The
typical performance curve “Input Offset Voltage vs Loop
Supply Voltage” describes this behavior.
FIGURE 1. Basic RTD Temperature Measurement Circuit.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| XTR103BP | A/D Converter (A-D) IC; Resolution (Bits):16; Sample Rate:100SPS; Input Channels Per ADC:4; Input Channel Type:Differential; Data Interface:Serial; Package/Case:; DNL +/-:0.5LSB; Leaded Process Compatible:No; No. of Bits:16 RoHS Compliant: Yes |
| XTR103BU | 4-20mA Current Transmitter with RTD EXCITATION AND LINEARIZATION |
| XTR104 | A/D Converter (A-D) IC; Resolution (Bits):20; Sample Rate:100SPS; Input Channels Per ADC:4; Input Channel Type:Differential; Data Interface:Serial; Package/Case:24-SOIC; Leaded Process Compatible:No; No. of Bits:20 RoHS Compliant: Yes |
| XTR104AP | 4-20mA Current Transmitter with BRIDGE EXCITATION AND LINEARIZATION |
| XTR104AU | A/D Converter (A-D) IC; Resolution (Bits):16; Sample Rate:100SPS; Input Channels Per ADC:1; Input Channel Type:Differential; Data Interface:Serial; Package/Case:20-DIP; DNL +/-:0.5LSB; Leaded Process Compatible:No; No. of Bits:16 RoHS Compliant: No |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| XTR103BP | 制造商:BB 制造商全稱:BB 功能描述:4-20mA Current Transmitter with RTD EXCITATION AND LINEARIZATION |
| XTR103BU | 制造商:Texas Instruments 功能描述: |
| XTR104 | 制造商:BB 制造商全稱:BB 功能描述:4-20mA Current Transmitter with BRIDGE EXCITATION AND LINEARIZATION |
| XTR104AP | 制造商:BB 制造商全稱:BB 功能描述:4-20mA Current Transmitter with BRIDGE EXCITATION AND LINEARIZATION |
| XTR104AU | 制造商:Rochester Electronics LLC 功能描述:4-20 MA XMITTER - Bulk |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。