Dallas Semiconductor announced the DS1629 2-Wire Digital Thermometer and Real Time Clock, the first digital system component to incorporate a direct-to-digital temperature sensor and a real-time clock and Y2K-correct calendar on one chip. Previously, designs for digitally monitoring thermally sensitive instruments and operating equipment have required a separate chip for each function, with separate programming configurations and interfaces.

Chris Beaudoin, product manager, said, "Thermally sensitive environments often require that temperature changes be monitored over time. The DS1629 provides digital accuracy and programmability for both time and temperature while cutting down the number and size of components. This is particularly important when you're designing for compact spaces."

The digital thermometer is accurate to ý2ýC with 9-bit readouts in increments of 0.5ýC. The user can even fine-tune a thermostatic response for extra sensitive applications, yielding 13-bit readouts in increments of 0.03125ýC. The real-time clock/calendar counts time from seconds through years, with leap year compensation through 2100.

For timed and/or thermostatic interrupt functions, the DS1629 has open-drain alarm outputs that activate at user-defined setpoints. For example, the user can set an interrupt for a certain time or at time intervals, at certain temperatures, or at temperatures occurring at a certain time or over specific periods of time. An additional 32 bytes of memory are available as a notebook for general user data. All communication is accomplished through a standard two-wire serial interface.

Dallas continues in its quest to conquer this monitoring market single-handedly -- and is doing a good job at stirring the waters so that it is the first company to think of in any such project. The DS1629 is another part that doubles up in its functionality again using the 2-wire interface. The company has included enough smarts to allow the part to take over in all the applications that I understand at present: the DS1629 will open up many other possible application areas where, perhaps, the complications of providing time-related temperature monitoring have been daunting to the designer. With this solution external controls are minimized to the point of being incidental.