1 of 17

110405

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 93.75 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 750ms (MAX) to 93.75 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.maxim-ic.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