Startup

Start of

Conversion

Delay

(1)

26 ms

26 ms

TMP104

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SBOS564A

– NOVEMBER 2011 – REVISED NOVEMBER 2011

Conversion Rate (CR1, CR0)

The conversion rate bits (CR1 and CR0), located in the Configuration Register, configure the TMP104 for

conversion rates of 8 Hz, 4 Hz, 1 Hz, or 0.25 Hz (default). The TMP104 has a typical conversion time of 26 ms.

To achieve different conversion rates, the TMP104 performs a single conversion and then powers down and

waits for the appropriate delay set by CR1 and CR0. Table 7 shows the settings for CR1 and CR0.

Table 7. Conversion Rate Settings

CR1

CR0

CONVERSION RATE

0

0

0.25 Hz (default)

0

1

1 Hz

1

0

4 Hz

1

1

8 Hz

After power-up or general-call reset, the TMP104 immediately starts a conversion, as shown in Figure 12. The

first result is available after 26 ms (typical). The active quiescent current during conversion is 40

μA (typical at

+25

°C, V+ = 1.8 V). The quiescent current during delay is 1.0 μA (typical at +25°C, V+ = 1.8 V).

(1) Delay is set by CR1 and CR0.

Figure 12. Conversion Start

Conversion Modes

Shutdown Mode (M1 = 0, M0 = 0)

Shutdown mode saves maximum power by shutting down all device circuitry other than the serial interface,

reducing current consumption to typically less than 0.5

μA. Shutdown mode is enabled when bits M1 and M0 (in

the Configuration Register) read '00'. The device shuts down when the current conversion is completed.

One-Shot Mode (M1 = 0, M0 = 1)

The TMP104 features a One-Shot Temperature Measurement mode. When the device is in Shutdown mode,

writing '01' to bits M1 and M0 starts a single temperature conversion. During the conversion, bits M1 and M0

read '01'. The device returns to the shutdown state at the completion of the single conversion. After the

conversion, bits M1 and M0 read '00'. This feature is useful for reducing power consumption in the TMP104

when continuous temperature monitoring is not required.

As a result of the short conversion time, the TMP104 can achieve a higher conversion rate. A single conversion

typically takes 26 ms and an individual read can take place in less than 300

μs. When using One-Shot mode, 30

or more conversions per second are possible.

Continuous Conversion Mode (M1 = 1)

When the TMP104 is in Continuous Conversion mode (M1 = 1), continuous conversions are performed at a rate

determined by the conversion rate bits, CR1 and CR0 (in the Configuration Register). The TMP104 performs a

single conversion, and then powers down and waits for the appropriate delay set by CR1 and CR0. See Table 7

for CR1 and CR0 settings.

Copyright

© 2011, Texas Instruments Incorporated

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