AD8494ARMZ-R7

精密热电偶放大器，冷端补偿 Precision Thermocouple Amplifiers with Cold Junction Compensation

Product Details

The AD8494/AD8495/AD8496/AD8497are 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 either 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 on the data sheet for the optimized ambient temperature range of each part.

The AD8494/AD8495/AD8496/AD8497 allow a wide variety of supply voltages. With a 5 V single supply, the 5 mV/°C output allows the devices to cover nearly 1000 degrees of a thermo-couple’s temperature range.

The AD8494/AD8495/AD8496/AD8497 work with 3 V supplies, allowing them to interface directly to lower supply ADCs. They can also work with supplies as large as 36 V in industrial systems that require a wide common-mode input range.

**Product Highlights

**

1. Complete, precision laser wafer trimmed thermocouple signal conditioning system in a single IC package.

2. Flexible pinout provides for operation as a setpoint controller or as a standalone Celsius thermometer.

3. Rugged inputs withstand 4 kV ESD and provide over-voltage protection OVP up to

VS ± 25 V.

4. Differential inputs reject common-mode noise on the thermocouple leads.

5. Reference pin voltage can be offset to measure 0°C on single supplies.

6. Available in a small, 8-lead MSOP that is fully RoHS compliant.

**

**

**Applications**

.

J type thermocouple temperature measurement

.

Setpoint controller

.

Celsius thermometer

.

Universal cold junction compensator

.

White goods oven, stove top temperature measurements

.

Exhaust gas temperature sensing

.

Catalytic converter temperature sensing

### Features and Benefits

.

Low cost and easy to use

.

Pretrimmed for J type thermocouples

.

Internal cold junction compensation

.

High impedance differential input

.

Standalone 5 mV/°C thermometer

.

Reference pin allows offset adjustment

.

Thermocouple break detection

.

See data sheet for additional features.