DS18B20 Digital Temperature Sensor — 1-Wire, TO-92, -55°C to +85°C, with 4.7K Resistor

DS18B20 Digital Temperature Sensor — 1-Wire Interface, TO-92 Package

The DS18B20 is the industry-standard 1-Wire digital temperature sensor from Dallas/Maxim, measuring temperatures from -55°C to +85°C with ±0.5°C accuracy over the -10°C to +85°C range. Its single-wire digital interface means only one microcontroller pin is needed — and multiple DS18B20 sensors can share the same bus, each identified by a unique 64-bit serial number. Includes a 4.7kΩ pull-up resistor for immediate use.

Key Specifications

Parameter	Value
Interface	1-Wire (single digital pin)
Supply Voltage	3.0V – 5.5V
Temperature Range	-55°C to +85°C
Accuracy	±0.5°C (-10°C to +85°C)
Resolution	9–12 bit (programmable)
Conversion Time	93.75ms (9-bit) to 750ms (12-bit)
Package	TO-92 (3-pin through-hole)
Logic Levels	Logic High >2.2V / Logic Low <0.8V
Manufacturer	Dallas / Maxim (now Analog Devices)

Why Choose the DS18B20?

• Single-wire bus — only one GPIO pin required; multiple sensors can share the same wire
• Digital output — immune to electrical noise and long cable runs, unlike analog sensors (LM35, NTC thermistor)
• Unique 64-bit address — identify and address each sensor individually on a shared 1-Wire bus
• Programmable resolution — 9 to 12-bit resolution trades off speed vs. precision
• Parasitic power mode — can operate on just 2 wires (data + ground) without a separate power supply
• Compact TO-92 package — fits tight PCB areas or can be soldered to a cable for remote mounting
• Includes 4.7kΩ resistor — required pull-up for 1-Wire bus, included in the package

Typical Applications

• Arduino and Raspberry Pi temperature monitoring projects
• Multi-point temperature logging (multiple sensors on one pin)
• Thermostat and temperature controller builds
• Remote temperature sensing with long cable runs
• Heat sink and enclosure thermal monitoring
• Aquarium, greenhouse, and environmental monitoring
• 3D printer heated bed and hotend temperature sensing

Wiring (Arduino)

DS18B20 Pin	Connection
VDD (pin 3)	3.3V or 5V
GND (pin 1)	GND
DQ (pin 2)	Digital pin (e.g. D4) + 4.7kΩ pull-up to VDD

Frequently Asked Questions

Q: What libraries do I need for Arduino?

Install OneWire and DallasTemperature libraries via the Arduino Library Manager. These handle all 1-Wire protocol communication and make reading temperature as simple as calling sensors.getTempCByIndex(0).

Q: How many DS18B20 sensors can I connect to one pin?

Theoretically unlimited — each sensor has a unique 64-bit address. In practice, 10–20 sensors on a single bus is common. Use a stronger pull-up resistor (2.2kΩ) for longer buses or more sensors.

Q: What is parasitic power mode?

In parasitic mode, the sensor draws power from the data line, requiring only 2 wires (DQ + GND). This simplifies wiring for remote sensors but requires special timing considerations. For most projects, use standard 3-wire mode (VDD + GND + DQ).

Q: DS18B20 vs LM35 — which should I use?

The DS18B20 is better for: long cable runs, multiple sensors on one pin, noise-sensitive environments, and digital systems. The LM35 is simpler (direct analog output, no library needed) but is more susceptible to noise and requires one analog pin per sensor.

Package Contents

• 1× DS18B20 Digital Temperature Sensor (TO-92)
• 1× 4.7kΩ resistor (pull-up for 1-Wire bus)

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