DS18B20 Pinout
DS18B20 Temperature Sensor · 1-Wire digital thermometer, −55 to +125°C, each chip has a unique 64-bit address.
TO-92 flat (labelled) face toward you, pins down: left to right GND-DQ-VDD. DQ (the 1-Wire data line) needs a ~4.7kΩ pull-up to VDD.
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | GND | GND | Ground |
| 2 | DQ · DATA | I/O | 1-Wire data (needs 4.7kΩ pull-up to VDD) |
| 3 | VDD · VCC | Power | Supply + (3.0–5.5V) |
How to read the DS18B20 pinout
- 01
Find pin 1
One end of the chip has a half-circle notch or a dot; with the notch facing up, the top-left pin is pin 1.
- 02
Count counter-clockwise
Count counter-clockwise from pin 1: go down the left side first, then up the right side from the bottom.
- 03
Check the table below
Look up each pin's function by number in the table below; power/ground are color-coded, and alternate-function signals are in parentheses.
Frequently asked questions
What is the DS18B20 pin order?
Flat (printed) face toward you, pins pointing down: left to right GND, DQ, VDD. Getting this backwards is the most common wiring mistake.
Do I need a pull-up resistor?
Yes — DQ is an open-drain 1-Wire line and needs about a 4.7kΩ pull-up to VDD. Without it the bus cannot return high and the sensor will not respond.
What is "parasite power" mode?
You can tie VDD to GND and power the sensor from the DQ line through the pull-up. It saves a wire but needs a strong pull-up during temperature conversion; a dedicated VDD (3-wire) is more robust.
Pinout data comes from Analog Devices/Maxim DS18B20 datasheet (standard TO-92 numbering). Refer to the actual device datasheet as authoritative for the pinout.