LM20C-EVAL National Semiconductor, LM20C-EVAL Datasheet - Page 7

• Manufacturer Part Number: LM20C-EVAL
• Description: EVALUATION BOARD FOR LM20C
• Manufacturer: National Semiconductor

Specifications of LM20C-EVAL

• Sensor Type: Temperature
• Sensing Range: -55°C ~ 130°C
• Interface: Analog
• Sensitivity: ±5°C
• Voltage - Supply: 2.5 V ~ 5.5 V
• Embedded: No
• Utilized Ic / Part: LM20C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM20C-EVAL

4.0 LM20 micro SMD Light Sensitivity
Exposing the LM20 micro SMD package to bright sunlight
may cause the output reading of the LM20 to drop by 1.5V. In
a normal office environment of fluorescent lighting the output
voltage is minimally affected (less than a millivolt drop). In ei-
ther case it is recommended that the LM20 micro SMD be
5.0 Applications Circuits
Most CMOS ADCs found in ASICs have a sampled data comparator input structure that is notorious for causing grief to analog
output devices such as the LM20 and many op amps. The cause of this grief is the requirement of instantaneous charge of the
input sampling capacitor in the ADC. This requirement is easily accommodated by the addition of a capacitor. Since not all ADCs
have identical input stages, the charge requirements will vary necessitating a different value of compensating capacitor. This ADC
is shown as an example only. If a digital output temperature is required please refer to devices such as the LM74.
FIGURE 8. Suggested Connection to a Sampling Analog to Digital Converter Input Stage
FIGURE 7. Conserving Power Dissipation with Shutdown
FIGURE 6. Centigrade Thermostat
7
placed inside an enclosure of some type that minimizes its
light exposure. Most chassis provide more than ample pro-
tection. The LM20 does not sustain permanent damage from
light exposure. Removing the light source will cause LM20's
output voltage to recover to the proper value.
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