TMP116 datasheet(33/46 Pages) TI2

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TMP116, TMP116N

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SBOS740A – MAY 2017 – REVISED MAY 2019

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Application Information (continued)

8.1.1.2 Detailed Design Procedure

8.1.1.2.1

Noise and Averaging

The device temperature sampling distribution (without internal averaging) covers an area of approximately six

neighboring codes. The noise area of the six codes remains the same at full supply and full temperature range

with a standard deviation of approximately 1 LSB. The device provides an averaging tool for 8, 32, and 64

samples. As illustrated in Figure 7, even the 8-sample averaging reduces the internal noise distribution to a

theoretical minimum of 2 LSB. This averaging means that if the system temperature slowly changes and the

supply voltage is stable, then the 8-sample averaging can be enough to neutralize the device internal noise and

provide stable temperature readings. However, if the system temperature is noisy (such as when measuring air

flow temperatures) or noisy power supply line or intensive communication in the I2C line, then higher averaging

numbers are recommended to be used.

8.1.1.2.2

Self-Heating Effect (SHE)

During ADC conversion some power is dissipated that heats the device despite the small power consumption of

the TMP116. Consider the self-heating effect (SHE) for certain precise measurements. Figure 42 shows the

device SHE in still air at 25°C after the supply is switched on. The device package, is soldered to the 11-mm ×

20-mm × 1.1-mm size coupon board. The board is located horizontally, with the device on top. The TMP116 is in

continuous conversion mode with 64 sampling averaging and zero conversion cycle time. There is no digital bus

activity aside from reading temperature data one time each second. As shown in Figure 42, the SHE stabilization

time in still air is greater when the device dissipates more power.

Figure 42. Self-Heating in Still Air vs. Temperature and Dissipated Power

The SHE drift is strongly proportional to the device dissipated power. The SHE drift is also proportional to the

device temperature because the consumption current with the same supply voltage increases with temperature.

Figure 43 shows the SHE drifts versus temperature and dissipated power at 25°C for the same coupon board

and the same conditions described previously.

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