DS18B20_07 Datasheet, PDF (1/21 Pages) Dallas Semiconductor – Programmable Resolution 1-Wire Digital Thermometer

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FEATURES
ƒ Unique 1-Wire^® interface requires only one
port pin for communication
ƒ Each device has a unique 64-bit serial code
stored in an onboard ROM
ƒ Multidrop capability simplifies distributed
temperature sensing applications
ƒ Requires no external components
ƒ Can be powered from data line. Power supply
range is 3.0V to 5.5V
ƒ Measures temperatures from –55°C to
+125°C (–67°F to +257°F)
ƒ ±0.5°C accuracy from –10°C to +85°C
ƒ Thermometer resolution is user-selectable
from 9 to 12 bits
ƒ Converts temperature to 12-bit digital word in
750ms (max.)
ƒ User-definable nonvolatile (NV) alarm
settings
ƒ Alarm search command identifies and
addresses devices whose temperature is
outside of programmed limits (temperature
alarm condition)
ƒ Available in 8-pin SO (150mil), 8-pin μSOP,
and 3-pin TO-92 packages
ƒ Software compatible with the DS1822
ƒ Applications include thermostatic controls,
industrial systems, consumer products,
thermometers, or any thermally sensitive
system
DS18B20
Programmable Resolution
1-Wire Digital Thermometer
PIN ASSIGNMENT
DALLAS
18B20
123
NC 1
8 NC
NC ₂
7 NC
V_DD
3
6 NC
DQ 4
5 GND
8-Pin 150mil SO
(DS18B20Z)
12 3
(BOTTOM VIEW)
TO-92
(DS18B20)
DQ 1
NC 2
NC 3
GND 4
8
V_DD
7 NC
6 NC
5 _NC
8-Pin μSOP
(DS18B20U)
PIN DESCRIPTION
GND - Ground
DQ - Data In/Out
V_DD - Power Supply Voltage
NC - No Connect
DESCRIPTION
The DS18B20 Digital Thermometer provides 9 to 12–bit centigrade temperature measurements and has
an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18B20
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 DS18B20 can derive power
directly from the data line (“parasite power”), eliminating the need for an external power supply.
Each DS18B20 has a unique 64-bit serial code, which allows multiple DS18B20s to function on the same
1–wire bus; thus, it is simple to use one microprocessor to control many DS18B20s 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.
1-Wire is a registered trademark of Dallas Semiconductor.
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