2-Terminal Temperature-to-Current Thermometer Suitable for Use at the End of Long Wire Runs

By adding the LT3092 to a thermistor kit along with three 0.1% accuracy resistors and one final trim, a very accurate 2-terminal temperature-to-current converter can be built. This circuit measures 700μA operating current at 0°C, dropping by 2μA every degree until 100°C, at which point the current measures 500μA. The obvious advantage to this T-to-I converter over a T-to-V converter is that current remains constant regardless of the wire length—as long as there is sufficient voltage to meet the compliance of the LT3092 circuit while not exceeding its absolute maximum.