DS1822 Datasheet, PDF (1/20 Pages) Dallas Semiconductor – Econo 1-Wire Digital Thermometer

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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.
§ 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.
§ Measures temperatures from -55°C to +125°C
(-67°F to +257°F).
§ ±2.0°C accuracy from -10°C to +85°C.
§ Thermometer resolution is user-selectable
from 9 to 12 bits.
§ Converts temperature to 12-bit digital word in
750ms (max.)
§ User-definable nonvolatile (NV) alarm
settings.
§ Alarm search command identifies and
addresses devices whose temperature is
outside of programmed limits (temperature
alarm condition).
§ Software compatible with the DS18B20.
§ Applications include thermostatic controls,
industrial systems, consumer products,
thermometers, or any thermally sensitive
system.
DS1822
Econo 1-Wire Digital
Thermometer
PIN ASSIGNMENT
DALLAS
1822
123
NC 1
NC 2
V_DD
3
DQ 4
8 NC
7 NC
6 NC
5 GND
8-Pin 150mil SO
(DS1822Z)
12 3
(BOTTOM VIEW)
TO-92
(DS1822)
PIN DESCRIPTION
GND - Ground
DQ - Data In/Out
V_DD - Power Supply Voltage
NC - No Connect
DESCRIPTION
The DS1822 digital thermometer provides 9- to 12-bit centigrade temperature measurements and has an
alarm function with NV user-programmable upper and lower trigger points. The DS1822 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
±2.0°C over the range of –10°C to +85°C. In addition, the DS1822 can derive power directly from the
data line (“parasite power”), eliminating the need for an external power supply.
Each DS1822 has a unique 64-bit serial code, which allows multiple DS1822s to function on the 1-Wire
bus; thus, it is simple to use one microprocessor to control many DS1822s 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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