LM185-12 National Semiconductor, LM185-12 Datasheet - Page 6

• Manufacturer Part Number: LM185-12
• Description: Micropower Voltage Reference Diode
• Manufacturer: National Semiconductor

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Typical Applications
Calibration
1. Short LM385-1.2, adjust R3 for I
2. Remove short, adjust R2 for correct reading in centigrade
†
I
Calibration
1. Short LM385-1.2, adjust R3 for I
2. Remove short, adjust R2 for correct reading in ˚F
Q
I
Q
at 1.6V 2.4 mA
at 1.3V 500 µA
0˚C−100˚C Thermometer
0˚F−50˚F Thermometer
OUT
OUT
= temp at 1 µA/˚K
= temp at 1.8 µA/˚K
(Continued)
DS005518-30
DS005518-28
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METER THERMOMETERS
*2N3638 or 2N2907 select for inverse H
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.
Typical supply current 50 µA
†
‡
6
Select for operation at 1.3V
I
Q
Thermocouple
600 µA to 900 µA
Type
T
K
S
J
Micropower Thermocouple Cold Junction
Lower Power Thermometer
Coefficient
Seebeck
(µV/˚C)
52.3
42.8
40.8
6.4
Compensator
63.4 150
523 1.24k
432
412 953
( )
R1
FE
( )
R2
1k
5
Across R1
Voltage
@
15.60
12.77
12.17
1.908
(mV)
25˚C
DS005518-29
Across R2
DS005518-31
Voltage
14.32
11.78
11.17
1.766
(mV)
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