LM70CIMM-3 National Semiconductor, LM70CIMM-3 Datasheet - Page 11

• Manufacturer Part Number: LM70CIMM-3
• Description: Temperature Sensor IC
• Manufacturer: National Semiconductor

Specifications of LM70CIMM-3

• Peak Reflow Compatible (260 C): No
• Ic Function: Temperature Sensor IC
• Supply Voltage Max: 5.5V
• Leaded Process Compatible: No
• Mounting Type: Surface Mount
• Operating Temperature Range: -40°C To +85°C
• Temperature Sensor Function: Temp Sensor
• Output Type: Digital
• Resolution: 10+SignBit
• Package Type: MSOP
• Operating Temperature (min): -55
• Operating Temperature (max): 150C
• Operating Temperature Classification: Military
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

2.0 Serial Bus Timing Diagrams
3.0 Application Hints
To get the expected results when measuring temperature with
an integrated circuit temperature sensor like the LM70, it is
important to understand that the sensor measures its own die
temperature. For the LM70, the best thermal path between
the die and the outside world is through the LM70's pins. In
the MSOP-8 package the ground pin is connected to the back
side of the LM70 die and thus has the most effect on the die
temperature. Although the other pins will also have some ef-
fect on the LM70die temperature and therefore should not be
discounted. The LM70 will provide an accurate measurement
of the temperature of the printed circuit board on which it is
mounted, because the pins represent a good thermal path to
the die. A less efficient thermal path exists between the plastic
a) Reading Continuous Conversion - Single Eight-Bit Frame
b) Reading Continuous Conversion - Two Eight-Bit Frames
c) Writing Shutdown Control
FIGURE 7. Timing Diagrams
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package and the LM70 die. If the ambient air temperature is
significantly different from the printed circuit board tempera-
ture, it will have a small effect on the measured temperature.
In probe-type applications, the LM70 can be mounted inside
a sealed-end metal tube, and can then be dipped into a bath
or screwed into a threaded hole in a tank. As with any IC, the
LM70 and accompanying wiring and circuits must be kept in-
sulated and dry, to avoid leakage and corrosion. This is
especially true if the circuit may operate at cold temperatures
where condensation can occur. Printed-circuit coatings and
varnishes such as Humiseal and epoxy paints or dips are of-
ten used to insure that moisture cannot corrode the LM70 or
its connections.
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