DS18B20-PAR
1-Wire Parasite-Power
Digital Thermometer
www.maxim-ic.com
FEATURES
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Unique 1-Wire interface requires only one
port pin for communication
Derives power from data line (“parasite
power”)—does not need a local power supply
Multi-drop capability simplifies distributed
temperature sensing applications
Requires no external components
±0.5°C
accuracy from –10°C to +85°C
Measures temperatures from –55°C to
+100°C (–67°F to +212°F)
Thermometer resolution is user-selectable
from 9 to 12 bits
Converts temperature to 12-bit digital word in
750 ms (max.)
User–definable non-volatile temperature
alarm settings
Alarm search command identifies and
addresses devices whose temperature is
outside of programmed limits (temperature
alarm condition)
Software compatible with the DS1822-PAR
Ideal for use in remote sensing applications
(e.g., temperature probes) that do not have a
local power source
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PIN ASSIGNMENT
DALLAS
18B20P
1 2 3
(BOTTOM VIEW)
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TO-92
(DS18B20-PAR)
PIN DESCRIPTION
GND - Ground
DQ
- Data In/Out
NC
- No Connect
DESCRIPTION
The DS18B20-PAR 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-PAR does not need an external power supply because it derives power directly from the data
line (“parasite power”). The DS18B20-PAR communicates over a 1-Wire bus, which 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 +100°C and is accurate to
±0.5°C
over a range of –10°C to
+85°C.
Each DS18B20-PAR has a unique 64-bit identification code, which allows multiple DS18B20-PARs to
function on the same 1–wire bus; thus, it is simple to use one microprocessor to control many DS18B20-
PARs 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.
1 of 19
GND
DQ
NC
1 2
3
101207
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