Table 7-3. 16-Bit Temperature Data Format (continued)

TEMPERATURE (°C)(1)

DIGITAL OUTPUT (BINARY)

HEX

0.0078125

0000 0000 0000 0001

0001

0

0000 0000 0000 0000

0000

-0.0078125

1111 1111 1111 1111

FFFF

-0.0625

1111 1111 1111 1100

FFF8

–0.25

1111 1111 1110 0000

FFE0

–25

1111 0011 1000 0000

F380

–40

1110 1100 0000 0000

EC00

(1)

The resolution for the Temp ADC in Internal Temperature mode is 0.0078125°C/count.

7.3.2 Averaging

The device supports 4 different averaging modes to help suppress noise as well as reduce the impact from

external temperature fluctuations. The AVG [3:2] bits in the Configuration register can be programmed to control

the averaging behavior of the device:

• No Averaging [00b]: The device performs 1 single conversion per conversion period, and temperature result

is stored immediately into the Temp_Result register at the end of every conversion.

1 second

1 Conversion

~11 ms

Standby

Standby

Temperature

result stored

Standby

Standby

Figure 7-2. Conversion (1Hz Conversion Rate Example) With No Averaging

• Back-to-back Averaging [01b or 10b]: The device accumulates and stores a number of temperature

conversion results and reports the average of all the stored results at the end of the process. If AVG [3:2] is

set to 01b, 4 conversions are executed back-to-back in every conversion period and the average temperature

result is stored into the Temp_Result register after the 4 conversions are completed. If AVG [3:2] is set to 10b,

8 conversions are executed back-to-back in every conversion period and the average temperature result is

stored into the Temp_Result register after the 8 conversions are completed.

The Back-to-back Averaging feature is useful to reduce the impact from the device’s internal noise sources,

such as the device thermal noise and ADC quantization noise. Figure 6-8 and Figure 6-9 illustrates the

improved noise performance of the device as a result of turning on the 8x regular averaging. Note Back-to-

back Averaging increases the average current consumption of the device due to increased active conversion

time in every conversion period.

1 second

4 Conversion

~44 ms

Standby

Standby

Temperature

result stored

Standby

Standby

Temperature

result stored

Temperature

result stored

Temperature

result stored

Figure 7-3. Conversion (1Hz Conversion Rate Example) With 4x Back-to-back Averaging

• Moving 4x Averaging [11b]: If AVG [3:2] is set to 11b, the device performs 1 single conversion per conversion

period, and the new temperature result is averaged together with the results from the 3 previous conversion

period and stored into the Temp_Result register. The moving averaging feature can be beneficial to filter out

fluctuation of external temperature source by taking multiple samples and averaging out the result.

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TMP118

SNIS237 – DECEMBER 2024

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