Description
The DS18B20 is a programmable-resolution 1-Wire digital temperature sensor in a 3-pin TO-92 package. 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 .
Critical limitations for the (CHN) variant: Chinese-manufactured DS18B20-compatible chips may not fully implement the original datasheet features. Parasitic power mode is reported to fail on some clones . The EEPROM alarm function may be absent . Temperature accuracy outside the ±0.5°C band has been observed in testing . For applications where precision or long-term reliability matters, verify the chip’s behavior before deployment.
Features
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1-Wire Interface: Requires only one data pin (plus ground) for communication .
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Programmable Resolution (9–12 bits): User-selectable resolution for speed vs. precision trade-off .
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Wide Temperature Range: -55°C to +125°C, with ±0.5°C accuracy from -10°C to +85°C .
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Unique 64-Bit Serial Code: Multiple sensors can share one bus without address conflicts .
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Parasite Power Capable: Can operate without external supply (2-wire mode) — verify on (CHN) units .
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No External Components Required: Integrated sensor and EEPROM reduce component count .
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User-Programmable Alarm: Nonvolatile upper/lower trigger points with alarm search .
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TO-92 Package: Standard 3-pin through-hole package for easy prototyping .
Technical Specifications
| Parameter | Specification (Original DS18B20) |
|---|---|
| Temperature Range | -55°C to +125°C |
| Accuracy | ±0.5°C (-10°C to +85°C) |
| Resolution | 9–12 bits programmable |
| Supply Voltage | 3.0V to 5.5V |
| Interface | 1-Wire (DQ + GND minimum) |
| Package | TO-92 (3-pin) |
| Unique ID | 64-bit ROM code |
| Alarm Function | Nonvolatile upper/lower limits |
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