Ad8495 Armz Thermal K-Type Thermocouple Amplifier Analog Output Module

The thermocouple signal is very small and must be amplified by considerable gain before it can be properly sampled by most ADCs. The AD8495 thermocouple amplifier provides a simple, low-cost solution for thermocouple temperature measurement. The integrated temperature sensor performs cold junction compensation. The fixed gain instrumentation amplifier amplifies the small voltage of the thermocouple to provide a 5 mV/°C output.

The amplifier has high common-mode rejection and is capable of rejecting common-mode noise that may be picked up by long leads of thermocouples. For extra protection, the amplifier's high-impedance input allows for easy additional filtering.

The AD849x output is a voltage proportional to the thermocouple measurement junction temperature (TMJ). To derive the measured temperature from the AD849x output voltage, use the transfer function TMJ=(VOUT−VREF)/(5mV/°C), VOUT=(TMJ×5mV/°C)+VREF. The AD8495 and AD8497 (Type K) instrumentation amplifiers have a gain of 122.4. With a single 5V supply, the 5mV/°C output allows these devices to cover a thermocouple temperature range of nearly 1000 degrees.