Precision digital-output temperature sensors from STM

The digital sensors, in standard 8-lead TSSOP and SO-8 packages, are intended for use in any control application where a processor with an I2C bus/SMBus needs to take action based on an accurate digital reading of the local temperature, or where an alarm or interrupt is required when a preset temperature level is reached. They use a band-gap temperature sensor, with a programmable 9-bit to 12-bit sigma-delta ADC (analog to digital converter) to digitize the temperature reading to a resolution of up to 0.0625 degrees C. The STTS75 devices are factory-calibrated and require no external components.

Accuracy is plus or minus 3 degrees over the full -55 to +125 degrees C temperature range, and plus or minus 2 degrees from -25 to +100 degrees C. The sensors are designed for a supply voltage range of 2.7V to 5.5V and have a low operating current of 75uA (typical) at 3.3V. In the power-saving shutdown mode the standby current is a very low 1uA maximum. Power-up defaults enable standalone operation as a thermostat, and both temperature and hysteresis values are programmable.

Typical applications include any product with a hard drive – including laptops, servers and some set-top boxes – plus medical equipment, industrial controllers and LCD backlighting. Brighter displays and higher speed circuits mean more heat is being generated, which must be dissipated in ever-smaller packages. This challenge for thermal management in consumer and industrial electronics means that the temperature of ICs and ambient air must be carefully monitored to prevent over-heating and damage.