Functional Diagrams
DESCRIPTION
The DS18B20 digital thermometer provides 9-bit
to 12-bit Celsius temperature measurements and
has an alarm function with nonvolatile userprogrammable
upper and lower trigger points.
The DS18B20 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 DS18B20 can derive power directly
from the data line (“parasite power”), eliminating
the need for an external power supply.
Each DS18B20 has a unique 64-bit serial code,
which allows multiple DS18B20s to function on
the same 1-Wire bus. Thus, it is simple to use one
microprocessor to control many DS18B20s
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.

Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
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
 Thermometer Resolution is User Selectable
from 9 to 12 Bits
 Converts Temperature to 12-Bit Digital Word 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)
 Available in 8-Pin SO (150 mils), 8-Pin μSOP,
and 3-Pin TO-92 Packages
 Software Compatible with the DS1822
 Applications Include Thermostatic Controls,
Industrial Systems, Consumer Products,
Thermometers, or Any Thermally Sensitive
System