LM385M3X-1.2 National Semiconductor, LM385M3X-1.2 Datasheet - Page 7

• Manufacturer Part Number: LM385M3X-1.2
• Description: IC VREF MICROPWR DIODE SOT23-3
• Manufacturer: National Semiconductor

Specifications of LM385M3X-1.2

• Reference Type: Shunt
• Voltage - Output: 1.235V
• Tolerance: ±2%
• Temperature Coefficient: 150ppm/°C
• Number Of Channels: 1
• Current - Cathode: 20µA
• Current - Output: 20mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: TO-236-3, SC-59, SOT-23-3
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Input: -
• Current - Quiescent: -
• Other names: LM385M3X-1.2TR

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