FEATURES
Low cost and easy to use
Pretrimmed for J or K type thermocouples
Internal cold junction compensation
High impedance differential input
Standalone 5 mV/°C thermometer
Reference pin allows offset adjustment
Thermocouple break detection
Laser wafer trimmed to 1°C initial accuracy and
0.025°C/°C ambient temperature rejection
Low power: <1 mW at VS = 5 V
Wide power supply range
Single supply: 2.7 V to 36 V
Dual supply: ±2.7 V to ±18 V
Small, 8-lead MSOP
APPLICATIONS
J or K type thermocouple temperature measurement Setpoint controller
Celsius thermometer
Universal cold junction compensator
White goods (oven, stovetop) temperature measurements Exhaust gas temperature sensing
Catalytic converter temperature sensing

GENERAL DESCRIPTION
The AD8494/AD8495/AD8496/AD8497 are precision instrumentation amplifiers with thermocouple cold junction compensators on an integrated circuit. They produce a high level (5 mV/°C) output directly from a thermocouple signal by combining an ice point reference with a precalibrated amplifier. They can be used as standalone thermometers or as switched output setpoint controllers using a fixed or remote setpoint control.
The AD8494/AD8495/AD8496/AD8497 can be powered from a single-ended supply (less than 3 V) and can measure temperatures below 0°C by offsetting the reference input. To minimize self- heating, an unloaded AD849x typically operates with a total supply current of 180 μA, but it is also capable of delivering in excess of ±5 mA to a load.
The AD8494 and AD8496 are precalibrated by laser wafer trimming to match the characteristics of J type (iron-constantan) thermocouples; the AD8495 and AD8497 are laser trimmed to match the characteristics of K type (chromel-alumel) thermo- couples. See Table 1 for the optimized ambient temperature range of each part.