Digital Temperature Sensors Eye Low-Power Apps

Embarking as drop-in replacements for LM75, DS75, and TCN75A temperature sensor chips, the STxx75 series digital temperature sensors operate over a temperature range from -55°C to +125°C degrees C temperature range, making them suitable for low-power applications. They particularly target 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. The chips employ a band-gap temperature sensor with a programmable nine-bit to 12-bit sigma-delta ADC to digitize the temperature reading to a resolution up to 0.0625°C. Additionally, the devices come pre-calibrated and require no external components. Accuracy is ±3º over the full -55°C to +125°C temperature range and ±2º from -25°C to +100°C. They operate on supply voltages range 2.7V to 5.5V and specify an operating current of 75 mA at 3.3V. In shutdown mode, standby current is 1 mA maximum. Power-up defaults enable standalone operation as a thermostat and both temperature and hysteresis values are programmable. Available in SO-8 and MSOP8 (TSSOP8) packages, price is $0.70 each/1,000. STMICROELECTRONICS, Lexington, MA. (888) 787-3550.