8.2.1.2 Detailed Design Procedure

Configure the circuit as shown in Figure 40. Connect V_CC to a 3.3-V power supply and V_EE to ground. Make R1, R2 and R3 each 10-MΩ resistors. These three resistors are used to create the positive and negative thresholds for the window comparator (V_TH+ and V_TH–). With each resistor being equal, V_TH+ is 2.2 V and V_TH- is 1.1 V. Large resistor values such as 10-MΩ are used to minimize power consumption. The sensor output voltage is applied to the inverting and noninverting inputs of the two TLV702x's. The TLV7021 is used for its open-drain output configuration. Using the TLV702x allows the two comparator outputs to be Wire-Ored together. The respective comparator outputs will be low when the sensor is less than 1.1 V or greater than 2.2 V. V_OUT will be high when the sensor is in the range of 1.1 V to 2.2 V.