TMP117 datasheet(11/45 Pages) TI1

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1 Second

15.5 ms

124 ms,

8 Conv

Standby

Data_Ready

I C Temperature

8 Averages, 1-Hz CC

Standby

15.5 ms

1 Conversion Cycle

15.5 ms

Start-Up

Start of

Conversion

Active Conversion

TMP117

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SNOSD82 – JUNE 2018

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7.4 Device Functional Modes

7.4.1 Temperature Conversions

The TMP117 can be configured to operate in various conversion modes by using the MOD[1:0] bits. These

modes provide flexibility to operate the device in the most power efficient way necessary for the intended

application.

7.4.1.1 Conversion Cycle

When the device is operating in continuous conversion mode (see the Continuous Conversion Mode (CC)

section), every conversion cycle consists of an active conversion period followed by a standby period. The device

typically consumes 135 µA during active conversion, and the device typically consumes 1.25 µA during the low-

power standby period, as indicated in Table 1. Figure 14 shows a representative current consumption profile of a

conversion cycle. The duration of the active conversion period and standby period can be configured using the

CONV[2:0] and AVG[1:0] bits in the configuration register, thereby allowing the average current consumption of

the device to be optimized based on the application requirements. Changing the conversion cycle period also

affects the temperature result update rate because the temperature result register is updated at the end of every

conversion.

Figure 14. Conversion Cycle Timing Diagram

7.4.1.2 Averaging

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

to improve noise in the conversion results. When the TMP117 is configured to perform averaging, the device

executes the configured number of conversions. 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

and , 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. As shown in Figure 15, engineer can achieve

this improvement in noise performance with an increase in the active conversion time in a conversion cycle as a

trade-off. Note that this outcome will increase the average active current consumption. 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. On reset, the device is configured to report an average of eight

conversions with a conversion cycle time of 1 second.

Figure 15. Averaging Timing Diagram

TMP117 Datasheet(PDF) 11 Page - Texas Instruments

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