DS18B20 Digital Temperature Sensor TO-92

DS18B20 Digital Temperature Sensor (TO-92) reads temperature digitally and delivers a precise, easy-to-integrate solution for embedded and IoT projects. Designers use it for environmental monitoring, thermostats, and data-logging where a single-wire digital interface and wide temperature range simplify wiring and calibration.

Key Features:

• Digital 1-Wire Interface: Communicates over a single data line. Multiple sensors share one bus using unique 64-bit ROM codes.
• Wide Temperature Range: Measures from −55 °C to +125 °C for harsh and common environments.
• High Accuracy: Typical ±0.5 °C accuracy from −10 °C to +85 °C for many applications.
• Adjustable Resolution: Selectable 9-bit to 12-bit conversion resolution to trade speed for precision.
• Parasitic or External Power: Operates with a dedicated VDD or in parasite-power mode to simplify wiring.
• Compact TO-92 Package: Easy to mount on breadboards and PCBs for prototypes and small runs.

Technical Specifications:

• Supply Voltage (V_DD): 3.0 V to 5.5 V (external) or parasite-power option via data line.
• Temperature Range: −55 °C to +125 °C.
• Accuracy: Typically ±0.5 °C from −10 °C to +85 °C; see datasheet for full error table.
• Resolution: Configurable 9-bit to 12-bit (0.5 °C to 0.0625 °C step).
• Conversion Time: Up to 750 ms for 12-bit conversion (shorter for lower resolution).
• Standby Current: Sub-µA standby; active conversion current typically ~1 mA (refer to datasheet for exact figures).
• Interface: Maxim/Dallas 1-Wire protocol; unique 64-bit ROM ID per device.
• Alarm Function: Programmable high/low temperature alarm registers for autonomous alerts on the bus.

Mechanical Specifications:

• Package: TO-92 plastic through-hole encapsulation.
• Body Material: Molded epoxy suitable for standard electronic environments.
• Lead Finish: Tin-plated leads compatible with standard soldering processes.
• Mounting: Through-hole for PCB or use in-wire harness with heat-shrink for simple installations.

Dimensions:

• TO-92 Typical Body: Body width ~4.5 mm, height ~5.0–6.5 mm (varies by manufacturer). Check mechanical drawing for precise values.
• Lead Spacing and Length: Standard TO-92 lead spacing; trim leads for PCB insertion or wire connections as required.

Pinout and Wiring:

• Pin 1 (left): GND (connect to system ground). When you face the flat side of the TO-92 body with leads down, this is the left pin.
• Pin 2 (middle): DQ (1-Wire data line). Use a pull-up resistor (typically 4.7 kΩ for 3.3–5 V systems). The device can run in parasite power mode using this pin.
• Pin 3 (right): VDD (3.0–5.5 V) when not using parasite power.
• Wiring note: Place the pull-up resistor close to the controller. Add decoupling on VDD for noisy environments. For long buses, use lower pull-up resistance or bus master buffer for reliability.

Datasheet Reference:

• Download the official DS18B20 datasheet from Maxim Integrated (now Analog Devices) for electrical characteristics, timing diagrams, ROM commands, and application circuits.

Applications:

• Environmental Monitoring: Integrate into weather stations and HVAC sensing systems.
• IoT and Data Logging: Use in distributed sensor networks and single-wire daisy-chained deployments.
• Thermostats and Appliances: Implement temperature control and safety cutouts.
• Industrial and Automotive Prototyping: Employ in test rigs where wide temperature range and unique IDs matter.

Equivalent Models:

• DS18S20: Earlier 1-Wire temperature sensor with lower native resolution; use if legacy compatibility is required.
• MAX31820: Other Maxim/Analog Devices 1-Wire temperature variants; verify specs before substitution.
• Waterproof variants: Stainless steel probe versions with same DS18B20 die for immersion sensing applications.

Package Includes:

• 1 x DS18B20 Digital Temperature Sensor in TO-92