PRELIMINARY
DS18S20
High Precision
1-Wire
®
Digital Thermometer
www.dalsemi.com
FEATURES
Unique 1–Wire interface requires only one
port pin for communication
Multidrop capability simplifies distributed
temperature sensing applications
Requires no external components
Can be powered from data line. Power supply
range is 3.0V to 5.5V
Zero standby power required
Measures temperatures from –55°C to
+125°C. Fahrenheit equivalent is –67°F to
+257°F
±0.5°C
accuracy from –10°C to +85°C
Temperature is read as a 9–bit digital value
Converts temperature to digital word in
750 ms (max.)
User–definable, nonvolatile temperature
alarm settings
Alarm search command identifies and
addresses devices whose temperature is
outside of programmed limits (temperature
alarm condition)
Functionally compatible with DS1820 1-Wire
digital thermometer
Applications include thermostatic controls,
industrial systems, consumer products,
thermometers, or any thermally sensitive
system
PIN ASSIGNMENT
BOTTOM VIEW
DALLAS
DS18S20
1 2 3
1 2 3
DS18S20 To-92
Package
NC
NC
GND
DQ
VDD
V
DD
DQ
1
2
3
4
8
7
6
5
NC
NC
NC
GND
DS18S20Z
8-Pin SOIC (150 mil)
PIN DESCRIPTION
GND
DQ
V
DD
NC
-
-
-
-
Ground
Data In/Out
Power Supply Voltage
No Connect
DESCRIPTION
The DS18S20 Digital Thermometer provides 9–bit temperature readings which indicate the temperature
of the device.
Information is sent to/from the DS18S20 over a 1–Wire interface, so that only one wire (and ground)
needs to be connected from a central microprocessor to a DS18S20. Power for reading, writing, and
performing temperature conversions can be derived from the data line itself with no need for an external
power source.
Because each DS18S20 contains a unique silicon serial number, multiple DS18S20s can exist on the
same 1–Wire bus. This allows for placing temperature sensors in many different places. Applications
where this feature is useful include HVAC environmental controls, sensing temperatures inside buildings,
equipment or machinery, and process monitoring and control.
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050400
DALLAS [ DALLAS SEMICONDUCTOR ]
