TMP117 datasheet(12/50 Pages) TI2

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7.3 Feature Description

7.3.1 Power Up

After the supply voltage reaches within the operating range, the device requires 1.5 ms to power up before

conversions can begin. The device can be programmed to start up in shutdown mode as well. See the EEPROM

Programming section for more information. The temperature register reads –256 °C before the first conversion.

7.3.2 Averaging

Users can configure the device to report the average of multiple temperature conversions with the AVG[1:0]

bits to reduce noise in the conversion results. When the TMP117 is configured to perform averaging with AVG

set to 01, the device executes the configured number of conversions to eight. The device accumulates those

conversion results and reports the average of all the collected results at the end of the process. As shown in the

noise histograms of Figure 6-6 and Figure 6-7, the temperature result output has a repeatability of approximately

±3 LSBs when there is no averaging and ±1 LSB when the device is configured to perform eight averages.

Figure 7-2 shows the total conversion cycle time trade-off when using the averaging mode to achieve this

improvement in noise performance. Averaging will increase the average active current consumption due to

increasing the active conversion time in a conversion cycle. For example a single active conversion typically

takes 15.5 ms, so if the device is configured to report an average of eight conversions, then the active

conversion time is 124 ms (15.5 ms × 8). Use Equation 1 to factor in this increase in active conversion time

to accurately calculate the average current consumption of the device. The average current consumption of the

device can be decreased by increasing the amount of time the device spends in standby period as compared

to active conversion. Under the factory EEPROM settings, the device is configured to report an average of eight

conversions with a conversion cycle time of 1 second by default.

Averaging can be used in both the continuous conversion mode and the one-shot mode.

15.5 ms

124 ms

8 Conv

1 Second

Standby

8 Averages, 1-Hz CC

2C Temperature or

Configuration Register Read

Data_Ready Flag

Figure 7-2. Averaging Timing Diagram

TMP117

SNOSD82D – JUNE 2018 – REVISED SEPTEMBER 2022

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TMP117 bảng dữ liệu(PDF) 12 Page - Texas Instruments