DS18B20
Programmable Resolution
1-Wire Digital Thermometer
DESCRIPTION
The DS18B20 digital thermometer provides 9-bit
to 12-bit Celsius temperature measurements and
has an alarm function with nonvolatile user-
programmable 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.
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
PIN CONFIGURATIONS
MAXIM
18B20
1 2 3
V
DD
DQ
3
4
N.C.
N.C.
1
8
N.C.
N.C.
N.C.
GND
MAXIM
18B20
2
7
6
5
SO (150 mils)
(DS18B20Z)
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)
1 of 22
GND
DQ
V
DD
DQ
N.C.
N.C.
GND
1
2
3
4
8
7
6
5
V
DD
N.C.
N.C.
N.C.
1 2 3
(BOTTOM VIEW)
µSOP
(DS18B20U)
18B20
TO-92
(DS18B20)
1-Wire is a registered trademark of Maxim Integrated Products, Inc.
REV: 042208
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
