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LM61

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SNIS121J – JUNE 1999 – REVISED NOVEMBER 2016

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9 Power Supply Recommendations

In an extremely noisy environment, it may be necessary to add filtering to minimize noise pickup. TI recommends

a 0.1-µF capacitor be added between +VS to GND to bypass the power-supply voltage, as shown in Figure 13.

10 Layout

10.1 Layout Guidelines

10.1.1 Mounting

The LM61 can be applied easily in the same way as other integrated-circuit temperature sensors. It can be glued

or cemented to a surface. The temperature that the LM61 senses is within about 0.2°C of the surface

temperature that LM61's leads are attached to.

This presumes that the ambient air temperature is almost the same as the surface temperature; if the air

temperature is much higher or lower than the surface temperature, the actual temperature measured would be at

an intermediate temperature between the surface temperature and the air temperatures.

To ensure good thermal conductivity the backside of the LM61 die is directly attached to the GND pin. The lands

and traces to the LM61 are part of the printed-circuit board, which is the object whose temperature is being

measured.

Alternatively, the LM61 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 LM61 and accompanying wiring and circuits must be

kept insulated 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 often used to ensure that moisture cannot corrode the device or connections.

10.2 Layout Examples

Figure 17. Recommended Solder Pads for SOT-23 Package