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Rainbow Electronics DS1822 User Manual

Digital thermometer, Features, Pin assignment

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043001



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)

• ±

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
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)

Software compatible with the DS18B20

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 DS1822 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 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 same 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

(BOTTOM VIEW)

2 3

DS1822

Econo 1-Wire

®

Digital Thermometer

www.dalsemi.com

8-pin 150-mil SOIC

(DS1822Z)

TO-92

(DS1822)

DALLAS
1822

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

22

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