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MCP9808 Precision Temp Sensor

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by Ray

Digital I2C temperature sensor with +-0.5 C accuracy and a programmable alert output.

temperaturesensori2cdigitalalertmicrochipmsop-8
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MCP9808

Microchip · Temperature Sensor · MSOP-8

The MCP9808 is a digital temperature sensor with typical +-0.5 C accuracy over -20 C to 100 C, reporting over I2C. It has user-programmable temperature limits and an open-drain alert output that trips on over/under-temperature or a critical threshold, and three address pins let up to eight share a bus. It suits thermal management and monitoring.

Pinout

Pin Name Type Function
1 SDA bidirectional I2C/SMBus serial data. Open-drain bidirectional line; requires an external pull-up resistor. VIH ≥ 0.7·VDD, VIL ≤ 0.3·VDD; VOL ≤ 0.4 V at IOL = 3 mA. Supports 0-400 kHz clock.
2 SCL input I2C/SMBus serial clock input. Requires an external pull-up resistor. VIH ≥ 0.7·VDD, VIL ≤ 0.3·VDD; input current ±5 µA max. 0-400 kHz.
3 Alert output Temperature Alert output. Open-drain output requiring an external pull-up resistor. Programmable polarity (active-low or active-high) and operating mode (comparator/thermostat or interrupt). VOL ≤ 0.4 V at IOL = 3 mA; leakage IOH = 1 µA typ.
4 GND power_in Ground reference for the device. Connect to the system ground plane.
5 A2 input I2C slave address select bit 2. Tie to VDD or GND to set one of eight selectable slave addresses (0011 A2 A1 A0). Logic level latched at power-up.
6 A1 input I2C slave address select bit 1. Tie to VDD or GND to set part of the 3-bit user address.
7 A0 input I2C slave address select bit 0. Tie to VDD or GND to set part of the 3-bit user address.
8 VDD power_in Positive supply input, 2.7 V to 5.5 V. Bypass with a 0.1 µF ceramic capacitor placed close to the pin. IDD = 200 µA typ (400 µA max); ISHDN = 0.1 µA typ.

Key specifications

Parameter Value
Type Digital I2C temperature sensor
Accuracy +-0.25 C typ, +-0.5 C max (-20 to 100 C)
Resolution 0.0625 C (up to 12-bit)
Interface I2C / SMBus
Alert Programmable open-drain (over/under/critical)
Addresses 3 address pins (up to 8 on a bus)
Supply voltage 2.7 V to 5.5 V
Operating temperature -40 C to 125 C

Ordering variants

Same part, different packaging or reel option.

  • MCP9808MS
  • MCP9808T-MS
  • MCP9808MC
  • MCP9808T-MC

CAD (KiCad official)

  • Symbol: mcp9808.kicad_sym
  • Footprint: mcp9808.kicad_mod
  • 3D model: MSOP-8 body from KiCad Package_SO/MSOP-8_3x3mm_P0.65mm.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Microchip datasheet (53 pp, sha256 e7b6502f744c3e60, retrieved 2026-08-17, tier: manufacturer)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF