Electronic – Reasons to use an analog temperature sensor instead of a digital one


I'm designing a microcontroller-based system that includes a thermostat.

When choosing which temperature sensor to use, I noticed that analog ones have more or less the same power consumption, the same temperature range and the same cost as digital ones.

Aside from possibly having a higher resolution ADC on the MCU than the one included in the digital sensor chip, are there any advantages in using an analog temperature sensor over a digital one?

Best Answer

Analog temperature sensors are easier in general to attach to the end of wires to make a temperature probe. On the other hand digital temperature sensors are in IC packages that are generally designed to be placed on a circuit board. This means that the probe type of sensor till typically have less thermal mass and be easier to couple to the medium being measured. A digital type IC sensor can be mounted on a small probe board on the end of a cable but it has more thermal mass and the IC package material does isolate the sensor some from the measured medium.

There are some digital IC temperature sensors that you can put on your MCU board but then support the attachment of a diode used as a temperature sensor. The diode is much easier to remote as a probe if that is needed. The ADT7476 is one example of this type of sensor.