Datasheet
8
SBOS061B
www.ti.com
XTR105
T
MIN
100°C 200°C 300°C 400°C 500°C 600°C 700°C 800°C 900°C1000°C
–200°C 18.7/86.6 18.7/169 18.7/255 18.7/340 18.7/422 18.7/511 18.7/590 18.7/665 18.7/750 18.7/845
15000 9760 8060 6650 5620 4750 4020 3480 3090 2740
16500 11500 10000 8870 7870 7150 6420 5900 5360 4990
–100°C 60.4/80.6 60.4/162 60.4/243 60.4/324 60.4/402 60.4/487 60.4/562 60.4/649 60.4/732
27400 15400 10500 7870 6040 4990 4220 3570 3090
29400 17800 13000 10200 8660 7500 6490 5900 5360
0°C 100/78.7 100/158 100/237 100/316 100/392 100/475 100/549 100/634
33200 16200 10500 7680 6040 4870 4020 3480
35700 18700 13000 10000 8250 7150 6340 5620
100°C 137/75 137/150 137/226 137/301 137/383 137/453 137/536
31600 15400 10200 7500 5760 4750 3920
34000 17800 12400 9760 8060 6810 6040
200°C 174/73.2 174/147 174/221 174/294 174/365 174/442
30900 15000 9760 7150 5620 4530
33200 17400 12100 9310 7680 6490
300°C 210/71.5 210/143 210/215 210/287 210/357
30100 14700 9530 6980 5360
32400 16500 11500 8870 7320
400°C 249/68.1 249/137 249/205 249/274
28700 14000 9090 6650
30900 16200 11000 8450
500°C 280/66.5 280/133 280/200
28000 13700 8870
30100 15400 10500
600°C 316/64.9 313/130
26700 13000
28700 14700
700°C 348/61.9
26100
27400
800°C 374/60.4
24900
26700
MEASUREMENT TEMPERATURE SPAN ∆T (°C)
R
Z
/R
G
R
LIN1
R
LIN2
R
G
=
2(R
2
– R
Z
)(R
1
– R
Z
)
(R
2
– R
1
)
R
LIN1
=
R
LIN
(R
2
– R
1
)
2(2R
1
– R
2
– R
Z
)
R
LIN2
=
(R
LIN
+R
G
)(R
2
– R
1
)
2(2R
1
– R
2
– R
Z
)
R
2
= RTD resistance at T
MAX
where: R
1
= RTD resistance at (T
MIN
+ T
MAX
)/2
R
LIN
= 1kΩ (Internal)
EXAMPLE:
The measurement range is –100°C to +200°C for a 3-wire Pt100 RTD connection. Determine the values for R
S
, R
G
, R
LIN1
, and R
LIN2
. Look up the values
from the chart or calculate the values according to the equations provided.
METHOD 1: TABLE LOOK UP
For T
MIN
= –100°C and ∆T = –300°C, the 1% values are:
R
Z
= 60.4Ω R
LIN1
= 10.5kΩ
R
G
= 243Ω R
LIN2
= 13kΩ
METHOD 2: CALCULATION
Step 1: Determine R
Z
, R
1
, and R
2
.
R
Z
is the RTD resistance at the minimum measured temperature,T
MIN
= –100°C.
Using Equation 1 at right gives R
Z
= 60.25Ω (1% value is 60.4Ω).
R
2
is the RTD resistance at the maximum measured temperature, T
MAX
= 200°C.
Using Equation 2 at right gives R
2
= 175.84Ω.
R
1
is the RTD resistance at the midpoint measured temperature,
T
MID
= (T
MIN
+ T
MAX
)/2 = 50°C. R
1
is NOT the average of R
Z
and R
2
.
Using Equation 2 at right gives R
1
= 119.40Ω.
Step 2: Calculate R
G
, R
LIN1
, and R
LIN2
using equations above.
R
G
= 242.3Ω (1% value is 243Ω)
R
LIN1
= 10.413kΩ (1% value is 10.5kΩ)
R
LIN2
= 12.936kΩ (1% value is 13kΩ)
Calculation of Pt100 Resistance Values
(according to DIN IEC 751)
(Equation 1) Temperature range from –200°C to 0°C:
R
(T)
= 100 [1 + 3.90802 • 10
–3
• T – 0.5802 • 10
–6
•
T
2
– 4.27350 • 10
–12
(T – 100) T
3
]
(Equation 2) Temperature range from 0°C to +850°C:
R
(T)
= 100 (1 + 3.90802 • 10
–3
• T – 0.5802 • 10
–6
• T
2
)
where: R
(T)
is the resistance in Ω at temperature T.
T is the temperature in °C.
TABLE I. R
Z
, R
G
, R
LIN1
, and R
LIN2
Standard 1% Resistor Values for 3-Wire Pt100 RTD Connection with Linearization.
NOTE: The values listed in this table are 1% resistors (in Ω).
Exact values may be calculated from the following equa-
tions:
R
Z
= RTD resistance at minimum measured temperature.
NOTE: Most RTD manufacturers provide reference tables for
resistance values at various temperatures.
A 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 2.2mA. Refer to the
typical characteristic Under-Scale Current vs Temperature.
Increasingly positive input voltage (greater than the full-scale
input) will produce increasing output current according to the
transfer function, up to the output current limit of approxi-
mately 27mA. Refer to the typical characteristic Over-Scale
Current vs Temperature.