Temperature monitor with RTC targets battery-powered systems
Communication to the device is through an I2C interface. The wide power-supply range and minimal power requirement of the device allow for accurate time/temperature measurements in battery-powered applications. There are alarm outputs for over-temperature or for a specified time, that can be logically combined.
The digital thermometer provides 9-bit to 12-bit temperature readings that indicate the temperature of the device. No additional components are required; the device is a true “temperature-to-digital” converter.
The clock/calendar provides seconds, minutes, hours, day, day of the week, month, day of the month, and year. The end-of-the-month date is automatically adjusted for months with less than 31 days, including corrections for leap years. It operates in either a 12- or 24-hour format with AM/PM indicator in 12-hour mode. The crystal oscillator frequency is internally divided, as specified by device configuration. An open-drain output is provided that can be used as the oscillator input for a microcontroller.
For storage of general system data or time/temperature data logging, the device features 32 Bytes of SRAM. Applications for the device include networking equipment, industrial equipment, office equipment, thermal data loggers, or any microprocessor-based, thermally sensitive system.
The device measures temperatures from -55°C to +125°C and the real-time clock counts seconds, minutes, hours, day, day of the week, month, day of the month, and year, with leap-year compensation through the year 2100.
Specifications include; thermometer accuracy of ±2.0°C, user programmable thermometer resolution to 9, 10, 11, or 12 bits, user definable thermostatic and time alarm settings, dedicated open-drain alarm output, and 32 bytes of SRAM for general data storage.
Data is read-from/written-to through I2C. The MAX31629 has a 2.2 V to 5.5 V wide power-supply range and comes in an 8-pin TDFN package.