Low-Voltage, 1.8kHz PWM Output Temperature Sensors

The MAX6676/MAX6677 are high-accuracy, low-power temperature sensors with a single-wire output. The MAX6676/MAX6677 convert the ambient temperature into a ratiometric PWM output with temperature information contained in the duty cycle of the output square wave. The MAX6676 has an open-drain output and the MAX6677 has a push-pull output.

The MAX6676/MAX6677 are specified for operation with power-supply voltages from 1.8V to 3.6V, or from 3.6V to 5.5V (MAX6676 only). The typical unloaded supply current is 80µA. All devices feature a single-wire output that minimizes the number of pins necessary to interface with a microprocessor (µP). The output is a square wave with a nominal frequency of 1.8kHz (±20%) at +25°C. The output format is decoded as follows:

Temperature (°C) = 398.15 x (t1 / t2) - 273.15

Where t1 is fixed with a typical value of 0.24ms and t2 is modulated by the temperature. The MAX6676/ MAX6677 operate from -40°C to +125°C and are available in space-saving 6-pin SOT23 packages.Applications

* HVAC and Environmental Control * Industrial * Isolated Temperature Sensing * Portable Devices * Process Control * µP and µC Temperature Monitoring

* Simple Single-Wire, 1.8kHz PWM Output

* Operates Down to 1.8V

* High Accuracy

* ±1.5°C at TA= +25°C

* ±3.0°C at TA = 0°C to +85°C

* Operates from -40°C to +125°C

* Low 80µA Typical Current Consumption

* Small 6-Pin SOT23 Package