The MAX6666/MAX6667 are high-accuracy, low-cost, low-power temperature sensors with a single-wire output. The MAX6666/MAX6667 convert the ambient temperature into a ratiometric PWM output with temperature information contained in the duty cycle of the output square wave. The MAX6666 has a push-pull output and the MAX6667 has an open-drain output. The MAX6666/MAX6667 operate at supply voltages from +3V to +5.5V. The typical unloaded supply current at 5.0V is 200A. Both devices feature a single-wire output that minimizes the number of pins necessary to interface with a microprocessor (P). The output is a square wave with a nominal frequency of 35Hz (20%) at +25C. The output format is decoded as follows: Temperature (C) = 235 - (400 x t1) / t2 Where t1 is fixed with a typical value of 10ms and t2 is modulated by the temperature (Figure 1). The MAX6666/ MAX6667 operate from -40C to +125C and are available in space-saving SOT23 packages.