Rainbow Electronics DS18S20 - Manual

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FEATURES
•
Unique 1-wire interface requires only one
port pin for communication
•
Each device has a unique 64-bit serial code
stored in an on-board ROM
•
Multi-drop 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
•
Measures temperatures from –55°C to
+125°C (–67°F to +257°F)
• ±
0.5
°
C accuracy from –10°C to +85°C
•
9-bit thermometer resolution
•
Converts temperature in 750 ms (max.)
•
User-definable nonvolatile alarm settings
•
Alarm search command identifies and
addresses devices whose temperature is
outside of programmed limits (temperature
alarm condition)
•
Applications include thermostatic controls,
industrial systems, consumer products,
thermometers, or any thermally sensitive
system
PIN ASSIGNMENT
PIN DESCRIPTION
GND - Ground
DQ - Data In/Out
V
DD
- Power Supply Voltage
NC - No Connect
DESCRIPTION
The DS18S20 Digital Thermometer provides 9–bit centigrade temperature measurements and has an
alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18S20
communicates over a 1-wire bus that by definition requires only one data line (and ground) for
communication with a central microprocessor. It has an operating temperature range of –55°C to +125°C
and is accurate to
±
0.5
°
C over the range of –10°C to +85°C. In addition, the DS18S20 can derive power
directly from the data line (“parasite power”), eliminating the need for an external power supply.
Each DS18S20 has a unique 64-bit serial code, which allows multiple DS18S20s to function on the same
1–wire bus; thus, it is simple to use one microprocessor to control many DS18S20s distributed over a
large area. Applications that can benefit from this feature include HVAC environmental controls,
temperature monitoring systems inside buildings, equipment or machinery, and process monitoring and
control systems.
DS18S20
High Precision
1-Wire
®
Digital Thermometer
www.dalsemi.com
8-pin 150-mil SOIC
(DS18S20Z)
TO-92
(DS18S20)
1
(BOTTOM VIEW)
2 3
DALLAS
DS1820
1
GND
DQ
V
DD
2 3
NC
NC
NC
NC
GND DQ
V
DD
NC
6
8
7
5
3
1
2
4
DS
1
8
20