Design engineers sometimes have to interface the TC7106 and similar ADCs to “non-ideal” sensors. A very common problem is that the sensor often does not give a “zero” output where the design wants a zero reading. One example of a “non-ideal” sensor is a diode used as a temperature sensor. The diode typically changes –2mV per degree Celsius, but the change is from the diode’s forward voltage of 600mV or so. In order for the display to read “000” at 0.0 degrees, an offset must be provided. The differential inputs of the TC7106 yield an easy solution to the offset problem. Figure 1 shows a simple thermometer with a diode sensor. Because the diode voltage decreases as temperature increases, IN LO is connected to the diode temperature sensor. The IN HI input is connected to a trimpot which is used to cancel the diode’s forward voltage.