Temperature Monitoring Solutions ©

Ambient and component temperature has a decisive impact on the performance and

lifetime of electronic equipment. There is hardly any system without at least one sensor

to acquire temperature values and feed them back to the digital processing units or

analog control circuits. This application note provides an overview of three accurate and

cost-optimized solutions for a wide range of temperature sensing applications.

One of the simplest and lowest cost solutions features a forward biased diode (Fig. 1).

The voltage drop between anode and cathode is a function of both current and temperature.

Due to the silicon’s physical characteristics, a diode’s forward voltage will

vary with temperature by a ratio of ca -1.6 m V/K (K designates the difference of two

temperatures in °C). Driving the diode with a constant current will eliminate its dependency

of current and turn it into a temperature sensor with an almost linear output

characteristic. As self-heating of the diode will bias the measurement, it is important to

keep the forward current at a minimum. A few mA will be enough to enable temperature


Almost any type of rectifier diode will do the job. Diotec offers a wide range of solutions in

all commonly used packages:

Small Signal and HV Diodes

SMD Diodes and Rectifiers

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