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071107

ma

FEATURES

Requires no external components

port pin for communication

Operates over a -55°C to +125°C (-67°F to

+257°F) temperature range

Functions as a standalone thermostat with

user-definable trip-points

Provides 8-bit (1°C resolution) centigrade

temperature measurements

Accuracy is

±1°C over 0°C to +85°C range

Converts temperature to a digital word in 1

second (max)

Available in 3-pin PR35 and 8-pin SO

packages

Applications include thermostatic controls,

industrial systems, consumer products,

thermometers, or any thermally sensitive

system

PIN ASSIGNMENT

PIN DESCRIPTION

GND

- Ground

DQ

- Data In/Out and Thermostat Output

- Power Supply Voltage

NC

- No Connect

DESCRIPTION

The DS1821 can function as a standalone thermostat with user-programmable trip-points or as 8-bit

temperature sensor with a 1-Wire digital interface. The thermostat trip-points are stored in nonvolatile

memory, so DS1821 units can be programmed prior to system insertion for true standalone operation.

The DS1821 has an operating temperature range of –55°C to +125°C and is accurate to

±1°C over a range

of 0°C to +85°C. Communication with the DS1821 is accomplished through the open-drain DQ pin; this

pin also serves as the thermostat output.

DS1821

Programmable Digital Thermostat and

Thermometer

8-pin 208-mil SO

(DS1821S)

1

(BOTTOM VIEW)

2

3

DALLAS

DS1821

1 2

3

PR35

(DS1821)

6

3

1

2

4

8

7

5

DQ

GND

NC

NC

NC

NC

NC

1-Wire is a registered trademark of Dallas Semiconductor Corp.,

a wholly owned subsidiary of Maxim Integrated Products, Inc.

www.maxim-ic.com