Datasheet

LM185-2.5-N, LM285-2.5-N, LM385-2.5-N
SNVS743D –DECEMBER 1999–REVISED MARCH 2013 www.ti.com
Calibration
Calibration
1. Short LM385-2.5-N, adjust R3 for I
OUT
=temp at 1.8 μA/°K
1. Short LM385-2.5-N, adjust R3 for I
OUT
=temp at 1μA/°K.
2. Remove short, adjust R2 for correct reading in °F
2. Remove short, adjust R2 for correct reading in centigrade
Figure 20. 0°C–100°C Thermomemter Figure 21. 0°F–50°F Thermomemter
Adjustment Procedure
1. Adjust TC ADJ pot until voltage across R1 equals Kelvin temperature multiplied by the thermocouple Seebeck
coefficient.
2. Adjust zero ADJ pot until voltage across R2 equals the thermocouple Seebeck coefficient multiplied by 273.2.
Figure 22. Micropower Thermocouple Cold Junction Compensator
Thermocouple Type
(1)
Seebeck R1 R2 Voltage Across R1
Voltage Across R2
Coefficient (Ω) (Ω) @25°C
(mV)
(
μ
V/°C) (mV)
J 52.3 523 1.24k 15.60 14.32
T 42.8 432 1k 12.77 11.78
K 40.8 412 953Ω 12.17 11.17
S 6.4 63.4 150Ω 1.908 1.766
(1) Typical supply current 50 μA
8 Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: LM185-2.5-N LM285-2.5-N LM385-2.5-N