Programmable Digital Temperature Sensor DS18B20 TO-92 (DALLAS-Original)

Description

The DS18B20 is a programmable-resolution 1-Wire digital temperature sensor from Analog Devices (originally Dallas Semiconductor, now part of Analog Devices). It provides 9-bit to 12-bit Celsius temperature measurements over a -55°C to +125°C range, with ±0.5°C accuracy specified for the -10°C to +85°C range . The device communicates over a 1-Wire bus that requires only one data line (plus ground) for communication with a microcontroller, and can optionally derive power directly from the data line (“parasite power”), eliminating the need for an external supply .

Each DS18B20 has a unique 64-bit serial code stored in on-board ROM, allowing multiple sensors to share the same 1-Wire bus—making it ideal for distributed temperature monitoring in HVAC systems, building automation, and multi-point sensing applications . The sensor also features user-programmable nonvolatile alarm settings with upper and lower trigger points, and an alarm search command that identifies devices outside the programmed limits .

Why “DALLAS-Original” matters: The open-source community has documented that a significant portion of DS18B20 chips sold through unofficial channels are counterfeit or clone parts that do not meet the original datasheet specifications . Common issues with fakes include parasitic power mode failures, temperature offsets outside the ±0.5°C band, missing EEPROM functionality, and non-standard ROM codes . The “DALLAS-Original” designation indicates a genuine Analog Devices (Dallas/Maxim) part, which is critical for applications requiring guaranteed accuracy, long-term reliability, and full datasheet compliance. Authorized distributors (Digi-Key, Mouser, Farnell, RS Components) are the recommended source for genuine parts .

Features

• 1-Wire Interface: Requires only one data pin (plus ground) for communication, minimizing wiring complexity .

• Programmable Resolution (9–12 bits): User-selectable resolution for speed vs. precision trade-off .

• Wide Temperature Range: -55°C to +125°C, with ±0.5°C accuracy from -10°C to +85°C .

• Unique 64-Bit Serial Code: Multiple sensors can share one bus without address conflicts .

• Parasite Power Capable: Can operate without external supply (2-wire mode: DQ and GND) .

• No External Components Required: Integrated sensor and EEPROM reduce component count .

• User-Programmable Alarm: Nonvolatile upper/lower trigger points with alarm search .

• Genuine DALLAS/Analog Devices Part: Verified compliance with datasheet specifications, unlike many clones .

Technical Specifications