DS18B20 1-Wire thermometer connection guide

DS18B20 1-Wire thermometer TO-92 wiring guide with power, signal assignments, and bench checks.

TO-92

3 contacts Current package

Analog Devices / Maxim Integrated ·

Tape and reel.

Required

Power the device and a short 1-Wire bus from the same 3.3 V rail. The host drives low or releases the bus. Use the pull-up to return DQ high.

After a reset pulse, check that the device pulls the line low for presence. Use a ROM search if more than one device is on the bus.
Issue Convert T (0x44), then wait up to 750 ms at 12-bit resolution. Read the scratchpad with 0xBE and validate the CRC before accepting a sample.
An 85 °C reading immediately after power-up is the documented reset value. Confirm that conversion completed before using it.

Analog Devices / Maxim DS18B20 Rev. 6, pp. 1–5, 8 and 19.

Highlighted contacts are used in the required step or selected circuit. Select a contact to inspect it.

TO-92

Flat face toward you and leads down. Pins 1, 2, and 3 are left to right.

Supply return · Ground

Connect to the common ground plane or bench return.

Analog Devices / Maxim DS18B20 Rev. 6, pp. 1–5, 8 and 19.

The three package maps cover the bare sensor. Check polarity separately on cabled probes or third-party modules.

DS18B20 manufacturer documentation· Analog Devices / Maxim DS18B20 Rev. 6, pp. 1–5, 8 and 19.