DS1822
Econo 1-Wire Digital
Thermometer
BENEFITS AND FEATURES
• Unique 1-Wire® Interface Requires Only One
Port Pin for Communications
PIN ASSIGNMENT
DALLAS
1822
8
NC
NC
NC
VDD
DQ
1
2
3
4
o Can Be Powered from Data Line
o Power-Supply Range is 3.0V to 5.5V
7
6
5
NC
1 2 3
NC
• Reduced Component Count with Integrated
Temperature Sensor and Interface
o Requires No External Components
o Measures temperatures from -55°C to
+125°C (-67°F to +257°F)
GND
8-Pin 150mil SO
(DS1822Z)
o ±2.0°C Accuracy from -10°C to +85°C
o Thermometer Resolution is User-Selectable
from 9 to 12 Bits
o Converts Temperature to 12-Bit Digital Word
in 750ms (max)
• Simplifies Distributed Temperature Sensing
with Multidrop Capability
1
2
3
o Each Device Has a Unique 64-Bit Serial
Code Stored in an On-Board Device
(BOTTOM VIEW)
o Flexible, User-Definable Nonvolatile
(NV) Alarm Settings with Alarm Search
Command Identifies Devices with
TO-92
(DS1822)
Temperatures
Limits
o Software compatible with the DS18B20
Outside
Programmed
PIN DESCRIPTION
GND - Ground
• Applications Include Thermostatic Controls,
Industrial Systems, Consumer Products,
Thermometers, or Any Thermally Sensitive
System
DQ
VDD - Power Supply Voltage
NC - No Connect
- Data In/Out
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 Maxim Integrated Products,
Inc.
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042815