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FEATURES

Temperature measurements require no

external components with ±1°C accuracy

Measures temperatures from -55°C to

+125°C; Fahrenheit equivalent is -67°F to

+257°F

Temperature resolution is configurable from 9

to 12 (default) bits (0.5°C to 0.0625°C

resolution)

Maximum conversion time (9-bit resolution)

of 150 ms

Thermostatic settings are user-definable

Data is read/written via a 2-wire serial

interface (open drain I/O lines); 3-bit

addressability

Wide power supply range (2.7V - 5.5V)

Applications include personal computers,

cellular telephones, office equipment, or any

thermally sensitive system

8-pin, 150-mil SOIC package and 8-pin µSOP

package

PIN ASSIGNMENT

PIN DESCRIPTION

SDA

- 2-Wire Serial Data Input/Output

SCL

- 2-Wire Serial Clock

GND

- Ground

- Thermostat Output Signal

- Chip Address Input

- Chip Address Input

- Chip Address Input

- Power Supply Voltage (+5V)

DESCRIPTION

The DS1721 2-Wire Digital Thermometer and Thermostat provides 12-bit temperature readings which

indicate the temperature of the device. Thermostatic settings and temperature readings are all

communicated to/from the DS1721 over a simple 2-wire serial interface. No additional components are

required; the device is truly a “temperature-to-digital” converter.

The DS1721 has three address bits that allow a user to multidrop up to eight sensors along the 2-wire bus,

greatly simplifying the bussing of distributed temperature sensing networks.

temperature TH. The output remains active until the temperature is equal to or below the user-defined

user.

For applications that require faster conversion times, the user can adjust the readout resolution from 12 to

9 bits, effectively reducing the conversion time from 1.2 s (MAX) to 150 ms (MAX). This is particularly

useful in applications where temperature changes large magnitudes very rapidly.

Applications for DS1721 include personal computers/services, cellular telephones, office equipment, or

any microprocessor-based, thermally sensitive system.

DS1721

2-Wire Digital Thermometer

and Thermostat

www.dalsemi.com

18

27

36

45

*

DS1721U

8-PIN µ-SOP

SDA

SCL

GND

1

8

2

7

3

6

4

5

DS1721S

8-Pin SOIC (150-mil)

SDA

SCL

GND