LT1025ACJ8 Datasheet, PDF (8/12 Pages) Linear Technology – Micropower Thermocouple Cold Junction Compensator

LT1025
TYPICAL APPLICATIO S
Differential Thermocouple Amplifier
–
TYPE K^†
V_CM
C1*
R1
10k
0.1%
R3
1M
0.1%
V⁺
–
+ _R2
10k
0.1% _R4
1M
5V** _0.1%
LTKA0x^††
+
V^–
C2*
V_IN
V_O
LT1025
GND
R5
3k
10mV/°C
R9
(V^–)(10k)
=
100k V_OUT (MAX)
V^–
–15V
V_OUT
R6
10mV/°C
7.5k
1%
R7
500
FULL-SCALE
TRIM
R8
5k
1%
*C1 AND C2 FILTER RIPPLE AND NOISE, BUT WILL LIMIT AC COMMON-MODE REJECTION
IF NOT MATCHED. SUGGESTED VALUES ARE 0.001µF TO 0.1µF
**USE LOWEST POSSIBLE SUPPLY VOLTAGE TO MINIMIZE INTERNAL TEMPERATURE RISE
† _{FOR BEST ACCURACY, THERMOCOUPLE RESISTANCE SHOULD BE LESS THAN 100Ω}
†† _{OR EQUIVALENT. SEE “AMPLIFIER CONSIDERATIONS”}
8
Utilizing Negative LT1025 Drive to Accommodate Grounded Thermocouple*
15V
R7
15k
V_IN
6V
LT1025 ^VO
GND
–10mV/°C
R4
R5
141k
47k
–15V _R6
10k
–+
1µF
TYPE E
15V
–
LTKA0x^††
+
–15V
R1
1k
1%
C1
0.1µF
R2
100Ω
R3
141k
1% _VOUT
10mV/°C
0°C TO 500°C
*SEE “REVERSING THE POLARITY OF THE 10mV/°C OUTPUT”
†† _{OR EQUIVALENT. SEE “AMPLIFIER CONSIDERATIONS”}
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