Analog Devices Inc./Maxim Integrated

The ADT6401/ADT6402 are trip point temperature switches available in a 6-lead SOT-23 package. Each part contains an internal band gap temperature sensor for local temperature sensing. When the temperature crosses the trip point setting, the logic output is activated. The ADT6401 logic output is active low and open-drain. The ADT6402 logic output is active high and push-pull. The temperature is digitized to a resolution of 0.125°C (11-bit). The pin-selectable trip point settings are 10°C apart starting from −45°C to +5°C for undertemperature switching, and from 45°C to 115°C for overtemperature switching.These devices typically consume 30 μA of supply current. Hysteresis is pin selectable at 2°C and 10°C. The temperature switch is specified to operate over the supply range of 2.7 V to 5.5 V.When the ADT6401/ADT6402 are used for monitoring tempera- tures from 45°C to 115°C, the logic output pin becomes active when the temperature goes higher than the selected trip point temperature. When the ADT6401/ADT6402 are used for monitoring tempera- tures from −45°C to +5°C, the logic output pin becomes active when the temperature goes lower than the selected trip point temperature.Product HighlightsΣ-Δ based temperature measurement gives high accuracy and noise immunity.Wide operating temperature range from −55°C to +125°C.±0.5°C typical accuracy from −45°C to +115°C.Pin-selectable threshold settings from −45°C to +115°C in 10°C increments.Supply voltage is 2.7 V to 5.5 V.Supply current of 30 μA.Space-saving, 6-lead SOT-23 package.Pin-selectable temperature hysteresis of 2°C or 10°C.Temperature resolution of 0.125°C.ApplicationsMedical equipmentAutomotive Cell phones Hard disk drivesPersonal computersElectronic test equipmentDomestic appliancesProcess controlData Sheet, Rev. 0, 5/08

The ADT7422 is a high accuracy, digital I2C temperature sensor designed to meet the clinical thermometry specification of the ASTM E1112 standards when soldered onto the final printed circuit board (PCB).The ADT7422 contains an internal band gap reference, a temperature sensor, and a precision analog-to-digital converter (ADC). The ADT7422 provides a 16-bit temperature result with a resolution of 0.0078°C and an accuracy of up to ±0.1°C across the temperature range of 25°C to 50°C without the need for calibration after the PCB soldering process.Operating at 3.0 V, the average supply current is typically 210 μA. The ADT7422 has a shutdown mode that powers down the device and offers a shutdown current of typically 2.0 μA at 3.0 V. The ADT7422 is rated for operation over the −40°C to +125°C temperature range.Pin A0 and Pin A1 are available for address selection and provide four possible I2C addresses for the ADT7422. The CT pin is an open-drain output that becomes active when the temperature exceeds a programmable critical temperature limit. The INT pin is also an open-drain output that becomes active when the temperature exceeds a programmable limit. The INT pin and CT pin can operate in comparator and interrupt event modes.Product HighlightsNo calibration or correction required by the user.Low power consumption.Long-term stability and reliability.High accuracy for industrial, instrumentation, and medical applications.ApplicationsVital signs monitoring (VSM)Medical equipmentResistance temperature detector (RTD) and thermistor replacementFood transportation and storageThermocouple cold junction compensationEnvironmental monitoring and heating, ventilation, and air conditioning (HVAC)Laser diode temperature control