12-bit SPI temperature sensor in SOIC-8
The Texas Instruments LM74CIM-5/NOPB is a digital local temperature sensor with 12-bit resolution and SPI output, packaged in an 8-pin SOIC (0.154" width, 3.90 mm body). The 12-bit conversion gives 0.0625°C per LSB — fine enough for thermal monitoring and fan control loops, though the ±5°C worst-case accuracy means you don't use it for precision oven control without calibration. The SPI interface avoids I2C address conflicts and pull-up resistors — a clean four-wire hookup to any MCU SPI port.
The test condition split confirms the accuracy spec is characterized over -10°C to 65°C, but the silicon itself survives the full 205°C span. That 150°C ceiling makes it viable for under-hood automotive, downhole instrumentation, or high-temperature industrial enclosures where the ambient near a hot processor or power stage exceeds 105°C. The Shutdown Mode feature drops quiescent current to microamps — useful in battery-backed telemetry or systems that cycle the sensor on only during thermal polling intervals. Without a separate enable pin, the shutdown is controlled via the SPI command set.
Accuracy budget and system-level fit
The ±5°C maximum over the full temperature range is the number to use for worst-case thermal shutdown thresholds — if the system must trip at 125°C, budget for a 130°C actual die temperature before the sensor reads 125°C. That 5°C guard band is typical for 12-bit local sensors without factory calibration. The 12-bit resolution means the digital output changes every 0.0625°C, but the noise floor of the internal bandgap reference limits effective resolution to about 0.25°C in practice. For thermal management (fan speed, overtemperature alarm, thermal throttling) that is more than adequate; for a thermostatic control loop with 0.1°C hysteresis, you'd step up to a 14- or 16-bit part.