AD8494CRMZ

Overview

The AD8494CRMZ is a precision thermocouple amplifier with integrated cold junction compensation, optimized for J-type thermocouples. It provides a linear output of 5 mV/°C directly from the thermocouple signal. The device operates on a single supply ranging from 2.7 V to 36 V or dual supplies of ±2.7 V to ±18 V. It features high impedance differential inputs and overvoltage protection up to VS ± 25 V. Initial accuracy is specified at ±1°C, with an ambient temperature rejection of 0.025°C/°C. The quiescent current is typically 180 μA, resulting in low power consumption of less than 1 mW at 5 V. The component is housed in an 8-lead MSOP package.

Feature Summary

• Integrated laser-wafer trimming matches J-type thermocouple characteristics for simplified signal conditioning.
• On-chip temperature sensor performs cold junction compensation to eliminate reference junction errors.
• Robust input stage withstands 4 kV ESD and provides overvoltage protection relative to supply rails.
• Differential inputs offer high common-mode rejection to block noise on long thermocouple leads.

Applications

• J-type thermocouple temperature measurement systems
• Setpoint controllers using fixed or remote voltage references
• Standalone Celsius thermometer implementations
• White goods such as ovens and stovetops
• Exhaust gas and catalytic converter temperature sensing

Procurement Notes

Verify the specific ordering suffix CRMZ corresponds to the MSOP-8 package and tube packaging configuration before procurement. Confirm that the ambient temperature range of 0°C to 50°C aligns with the target application environment requirements. Ensure the J-type thermocouple compatibility matches the sensor hardware in use.

Selection Notes

Select this component when J-type thermocouple interface is required with minimal external circuitry. The wide supply voltage range supports both low-voltage portable devices and industrial 36 V systems. Consider the 0°C to 50°C ambient optimization for standard laboratory or controlled environments rather than high-heat automotive applications.

Part Context

This part belongs to the AD849x family of precision thermocouple amplifiers. The AD8494 variant is specifically calibrated for J-type (iron-constantan) sensors, whereas the AD8495 serves K-type sensors. The AD8496 and AD8497 variants are optimized for higher ambient temperatures ranging from 25°C to 100°C.

Replacement Considerations

Public confirmed substitute part numbers: AD8494ARZ, AD8494ARMZ, AD8494BRMZ.