DS18B20 temperature sensor: specs and pinout
DS18B20 digital thermometer chip with a 1-Wire interface, 9 to 12-bit resolution and a -55 to +125 °C range; the probe is not covered.
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage | 3.0 V to 5.5 V | source Features |
| External supply | 3 V to 5.5 V | source Description (power section) |
| Temperature range | -55 °C to +125 °C | source Features |
| Accuracy | ±0.5 °C from -10 °C to +85 °C | source Features |
| Resolution | 9 to 12 bits, programmable | source Features |
| Conversion time | 750 ms maximum (12-bit) | source Features |
| Interface | 1-Wire | source Features |
Power
| Value | Source | |
|---|---|---|
| Supply | 3.0 V to 5.5 V external supply, or parasite power from the 1-Wire DQ line | source Power section (operating current note) |
| Current | Up to 1.5 mA operating current | source Power section (operating current note) |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently. Module header labels (VCC, GND, SDA, SCL…) come from the Compoden listing, not an official module schematic.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| GND (TO-92 pin 1) | Ground | 8-pin SOIC (DS18B20Z) pin 5 | source Detailed Pin Description, Table 1 (TO-92 pin numbers) | |
| DQ (TO-92 pin 2) | Data input/output; 1-Wire, open drain | Absolute maximum -0.5 V to +6.0 V on any pin relative to ground | Needs about 4.7-5 k pull-up (datasheet figures); 8-pin SOIC pin 4 | source Detailed Pin Description, Table 1 (TO-92 pin numbers) |
| VDD (TO-92 pin 3) | Optional supply pin; must be grounded for parasite-power operation | 3.0 V to 5.5 V; Absolute maximum -0.5 V to +6.0 V on any pin relative to ground | 8-pin SOIC pin 3 | source Detailed Pin Description, Table 1 (TO-92 pin numbers) |
Common mistakes
- Using parasite power above 100 °C: the datasheet says it is not recommended above 100 °C (source)
- Relying on a 5k pull-up alone during conversions on a shared bus: DQ may not have enough drive, so use a strong pull-up or external power (source)
- Expecting ±0.5 °C outside -10 °C to +85 °C: accuracy is specified only in that range (source)
What we could not confirm
- The datasheet used is an early PRELIMINARY revision. The current revision is not covered, so check ranges and supply against it before relying on them.
- Probe construction, waterproofing and cable colours are not in the chip datasheet. Cable wiring is not stated.
- Pinout is excluded.
- Pin rows are the DS18B20 chip's 3 TO-92 pins (early PRELIMINARY datasheet revision, a hosted copy). The probe's red/black/yellow wire colours are a probe convention from the listing, not from the datasheet.
Sources
- Dallas/Maxim DS18B20 datasheet, PRELIMINARY revision (official site: link).
- Copy hosted by a hosted copy (cdn.sparkfun.com/datasheets/Sensors/Temp/DS18B20.pdf). This copy is the old PRELIMINARY revision with a DS1820 pin header.
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