7.4 Device Functional Modes

7.4.1 Continuous Conversion Mode

When the TMP144 is in Continuous Conversion mode (M1 = 1), continuous conversions are performed at a rate

determined by the conversion rate bits, CR[1:0], in the configuration register. The TMP144 performs a single

conversion, then powers down and waits for the appropriate delay set by CR[1:0].

7.4.2 Shutdown Mode

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

reducing the current consumption to typically less than 0.5 μA. Shutdown mode is enabled when bits M[1:0] in

the configuration register are set as "00". If there is an active conversion ongoing, the device completes the

ongoing conversion, updates the temperature result register and shuts down.

7.4.3 One-Shot Mode

The TMP144 features a One-Shot Temperature Measurement mode. When the device is in Shutdown mode,

writing 01 to bits M[1:0] in the configuration register, starts a single temperature conversion. During the

conversion, the bits M[1:0] read 01. The device returns to the shutdown state at the completion of the single

conversion. After the conversion, bits M[1:0] read 00. This feature is useful for reducing power consumption in

the TMP144 when continuous temperature monitoring is not required.

As a result of the short conversion time, the TMP144 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.

7.4.4 Extended Temperature Mode

At power on, the TMP144 operates with a 12-bit temperature output. However, the TMP144 can be programmed

to operate in Extended Temperature mode, by setting the ETM bit in the configuration register as '1'. When

operating in extended temperature mode, the temperature result and temperature limit registers will be 13-bit

instead of 12-bit. This extra bit increases the range of the measurement. As shown in Table 7-1, with a 12-bit

temperature, the maximum value is 7FFh or 127.9 °C. With a 13-bit temperature value, however, the maximum

value is FFFh or 255.9 °C.

When the extended temperature mode is enabled, the EM bit for the temperature high limit register and

the corresponding temperature limit. However, if the application exits the ETM mode, by changing the bit from 1

to 0, this bit is not cleared. As a result, the limit will be right-shifted by 1 bit and halved unless the register values

are updated by the application.

The ETM bit value is considered at the end of every conversion cycle, but the limit registers can be updated

immediately after setting the bit to 1.

7.4.5 Temperature Alert Function

The TMP144 contains a temperature alert function that monitors the device temperature and compares the result

to the values stored in the temperature limit registers to determine if the device temperature is within these set

limits. As shown in Figure 7-2, if the result of the temperature conversion is greater than the value in the

temperature high limit register, the flag-high bit (FH) in the configuration register is set to '1'. If the result of the

temperature conversion register is less than the value in the temperature low limit register, the flag-low (FL) in

TMP144

SBOS891A – OCTOBER 2018 – REVISED FEBRUARY 2021

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