DS1820 Digital Thermometer
The DS1820 is a digital thermometer using a 1-wire interface for communications. Each DS1820 has a unique 64-bit serial code, enabling many DS1820 devices to be attached to the same 1-wire bus, for sensing temperature at many locations. The DS1820 has a 9-bit resolution, providing a +/-0.5 C accuracy from -10 C to +85 C, and an operating range of -55 C to +125 C.
The DS1820 is normally supplied in a TO-92 package - a 3 pin package similar to transistor packaging, and can be powered from the data line (known as parasitic power) or from the power line. When drawing power from the power line, the DS1820 voltage supply range is 3.0V to 5.5V.
The pinout arrangement of the DS1820 in the TO-92 confguration is:
- GND - Ground
- DQ - Data In/ Data Out
- VDD - Power
Figure 1: The DS1820
The DS1820 temperature sensor can be connected to a 1-wire network by soldering the leads of the temperature sensor to the network wires.
N.B. It is a good idea to use heat shrink over the soldered leads where possible, since it provides a bit of protection.