Ad8495 Armz Thermal K-type Thermocouple Amplifier Analog Output Module

Description

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.

Features And Specifications:

• Reference pin provides offset adjustment
• Thermocouple disconnection detection
• Laser wafer adjustment to 1°C initial accuracy and 0.025°C/°C ambient temperature suppression
• Low power consumption: <1 mW (VS = 5 V)
• Rugged input withstands 4kVESD and provides overvoltage protection (OVP) up to VS±25V
• Linearity error less than ±2°C, this error is only caused by the nonlinearity of the thermocouple

Pin Description:

1. +IN: Positive input,
2. -IN: negative input,
3. VOUT: output
4. REF reference input voltage: 1.24V, due to Q1 regulator limit, VCC maximum 18V, 5V recommended

Package Includes:

• 1 x Template
• 1 x Coupler
• 1 x Row of pins