Temperature monitor and real-time clock for battery-powered systems

March 31, 2014 // By Graham Prophet
Maxim Integrated has posted details of the MAX31629, an I2C digital thermometer and real-time clock (RTC) that integrates the functions of a real-time clock and a temperature monitor in a small-outline 8-pin TDFN package.

Communication to the device is through an I 2C 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.

Specifications include;

Measures Temperatures from -55°C to +125°C;

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

Thermometer Accuracy of ±2.0°C

Thermometer Resolution is User Programmable to 9, 10, 11, or 12 Bits

Thermostatic and Time Alarm Settings are User Definable

Dedicated Open-Drain Alarm Output

32 Bytes of SRAM for General Data Storage

Data is Read from/Written to through I 2C

2.2V to 5.5V Wide Power-Supply Range

8-Pin TDFN Package

Maxim; www.maximintegrated.com/datasheet/index.mvp/id/8338