Pin Configurations appear at end of data sheet

DESCRIPTION

The DS18S20 digital thermometer provides 9-bit Celsius temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18S20 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 ±0.5°C over the range of –10°C to +85°C. In addition, the DS18S20 can derive power directly from the data line (“parasite power”), eliminating the need for an external power supply.

Each DS18S20 has a unique 64-bit serial code, which allows multiple DS18S20s to function on the same 1-Wire bus. Thus, it is simple to use one microprocessor to control many DS18S20s 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.

Functional Diagrams

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

■ Multidrop 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)

■ ±0.5°C Accuracy from -10°C to +85°C

■ 9-Bit Thermometer Resolution

■ Converts Temperature in 750ms (max)

■ User-Definable Nonvolatile (NV) Alarm Settings

■ Alarm Search Command Identifies and Addresses Devices Whose Temperature is Outside Programmed Limits (Temperature Alarm Condition)

■ Applications Include Thermostatic Controls, Industrial Systems, Consumer Products, Thermometers, or Any Thermally Sensitive System