Should the sensor choose a digital interface or an analog interface?

Sensors are commonly used devices used to detect changes in physical states and quantify the measurement results at a specific scale or range. Generally, sensors can be divided into two types: analog and digital sensors. So which type of sensor is more suitable? Let's take temperature sensors as an example.

The difference between analog and digital sensors

Temperature sensors with analog outputs (such as TMP235 5) use analog output methods to communicate temperature, while sensors with digital outputs (such as TMP112 2) can directly transmit the determined temperature without system reprogramming.

Sensing Applications

In fact, systems with analog sensors require an ADC to digitize their output and use a lookup table to determine the temperature. Digital sensors already produce a digitized output of the measured temperature, which can be read back through a digital interface (such as I2C).

Calibration requirements

For analog sensors, the gain and offset of the ADC may need to be calibrated to achieve the required system accuracy. System temperature accuracy cannot be guaranteed in the lookup table because it is heavily dependent on the ADC reference error. Digital sensors do not need to be calibrated to obtain the accuracy guaranteed in the datasheet.

General experience

As a general rule of thumb, digital temperature sensors are preferred in almost all cases due to lower system integration complexity and higher out-of-the-box performance. Scenarios where digital sensors cannot be used include the lack of a suitable digital interface bus or cost limitations.