Maxim Integrated Products introduced the MAX6575L/H temperature sensor. This device features a unique single-wire digital interface that allows a microprocessor to interface with up to eight sensors using a single control line. Temperatures are sensed by measuring the time delay between the falling edge of an external triggering pulse and the falling edge of subsequent delays reported from the devices. Different sensors on the same I/O line use different timeout multipliers to avoid overlapping signals.

The MAX6575L/H features +/-3 degreeC accuracy max (+/-0.8 degreeC typical) at +25 degreeC and +/_5 degreeC accuracy max at +125 degreeC. It operates from a +2.7V to +5.5V supply and features a low 150 microamp supply current, making the MAX6575L/H ideal for use in portable, battery-powered equipment.

I wondered how long it would be that the industry allowed Dallas Semiconductor free rein in the single-wire interface market for sensors! Well this looks like Maxim is declaring itself with at least one part offering (and, without inside information, I would bet that this is not going to be the only offering.) The method of time multiplex is an interesting one and this could presumably be extended beyond eight devices if the sensor inputs are not required as frequently: that expansion would obviously be in slower process situations and Maxim is obviously tuned to this need by the two different versions being offered.

The accuracy ranges are ideal for many types of application while the power consumption is almost negligible. My guess is that Maxim developed this part for the automotive market -- for which it is temperature qualified -- but that it hopes to make the real profits from other uses; it probably will, if the company gets beyond just one type of sensor. Price is certainly not an issue.