Dallas Semiconductor today announced the DS1721 2-Wire Digital Thermometer and Thermostat, the latest in its growing family of digital temperature sensors. The DS1721 reports the temperature of a device or environment with an accuracy of ý1ýC over a very wide temperature range: -10ýC to +85ýC.

Michael Overlaur, product manager, said, "The ý1ýC is a maximum value, not a typical value as is often specified by other manufacturers. While there are similar devices that offer 2ýC accuracy, few devices offer 1ýC, and none at the DS1721's low cost. Accuracy is maintained over the full supply voltage range of 2.7V to 5.5V."

Broadening the temperature range, the DS1721 can provide accuracy of ý2.0ýC from -55ýC to +125ýC. The device can be used as a thermostat as well as a thermometer: the user sets high and low temperature limits, and the device reports when these limits have been reached. The temperature is reported in a 9- to 12-bit word, with increments as small as 0.0625ýC.

Overlaur said, "Other manufacturers' temperature sensing devices offer up to 10 bits of resolution only. With 12 bits, however, the DS1721 can detect problematic temperature changes sooner, enhancing system safety."

The device's three address lines can be used to multi-drop up to eight DS1721s along the 2-wire bus, greatly simplifying the bussing of distributed temperature sensing networks.

Applications for the DS1721 include personal computers, hard disk drives, office equipment, medical/scientific equipment, and any thermally sensitive system.

This part is impressive all round. The ý1ýC accuracy over -10ýC to +85ýC is not a number I have seen from anywhere else and it will get this part specified into places designers may have been hesitant about putting a single device in before; those may arise because of earlier needs to average readings from a couple or few sensors. With this part and an absolute failsafe design that shuts things down if the monitoring dies should be comforting for those designers. The price also makes it ideal for motherboard/drive use. People are often unaware how fast thermal runaway can take place in some environments and microseconds in shutting down an area, or applying additional cooling, can make the difference between saving the runaway part or media and losing service or data. The 12-bit resolution will enable those situations to be seen much faster by the monitoring controller.

Dallas have covered their bases with the additional temperature range, even with the doubling of maximum accuracy to ý2.0ýC, and there are probably few electronic environments where the part could not be used. The combination of raw accuracy for temperature measurement and high resolution for runaway detection is a killer mixture and the company is going to do really well with the product -- in measurement environments and in the many thermostat uses that exist as well.

The DS1721 is in production and is priced at $0.99 in 10,000-piece lots.