Maxim has announced a pair of temperature sensors, one accurate with an I2C bus, and the other with a multi-drop 1-Wire interface.

Maxim has announced a pair of temperature sensors, one accurate with an I2C bus, and the other with a multi-drop 1-Wire interface.
 

• MAX31889-blockMAX31889 is accurate:
• ±0.25°C accuracy from -20°C to +105°C
• ±0.65°C accuracy from -40°C to +125°C
• 16bit resolution
• 32 word temperature data FIFO
• high and low threshold temperature alarms
• 1.7V to 3.6V operation
• 68µA in operation
• 0.55µA stand-by
• 2 x 2 x 0.8mm 6pin µDFN package

The device uses a standard I2C serial interface (4 addresses available, more on request) to communicate with a host controller and two GPIO pins are available: one can can be configured to trigger a temperature conversion, while the other can be configured to generate an interrupt for selectable status bits.

A unique ROM ID allows a device to be traceable to US standards

MAX31825-blockMAX31825 is a 1-Wire device and so can be bussed with other sensors:

• ±1°C accuracy from 0°C to +70°C
• ±1.75°C accuracy from -45°C to +145°C
• Resolution selectable from 8 to 12bits (10bit converted in 80ms (max))
• high and low threshold temperature alarms
• 1.6 to 3.6V operation (2.3 to 3.6V for 1-Wire parasite power)
• 2.5µA stand-by
• 4kV HBM ESD Protection
• 6 bump WLP package

Communication is over a 1-Wire and power can be taken from this bus in some circumstances.

A unique 64bit serial code allows multiple MAX31825s to reside on the same 1-Wire bus.

Two address input pins that allow one of 64 different addresses to be selected to identify each sensor’s physical location.

“Allowing up to 64 devices, all connected to the same parasitically powered 1-Wire bus, with the precision of ±1°C accuracy,” said the company. “Each device has a unique code which can be optionally programmed with a location address, simplifying system design.”

Applications for the MAX31889 are foreseen in pharmaceutical cold chains, medical monitors and industrial automation, competing against RTD sensors.

MAX31825 offers up to 8x reduction in wiring compared with non-1-Wire interconnection, said Maxim, adding value where a lot of temperatures have to be sensed. Consumer devices and factory automation are seen as potential applications.