Part A
AD8495ARMZ
Компания Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7539 ПКС
- Package
- MSOP-8
- Series
- Интерфейс - интерфейсы датчиков и детекторов
Replacement verdict
Compatible functional replacement candidate
The AD8495ARMZ and AD8494ARMZ are functionally compatible thermocouple amplifier candidates sharing the same package, supply range, and output configuration, with the primary distinction being the factory-set thermocouple type and corresponding temperature range. The AD8495ARMZ is calibrated for K-type thermocouples, while the AD8494ARMZ is calibrated for J-type thermocouples, so substitution requires validation that the target thermocouple type matches the device calibration.
Package Type
High match
Output Type
High match
Supply Voltage Range
High match
Thermocouple Calibration
Validation required
Parts at a glance
Part B
AD8494ARMZ
Компания Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 9077 ПКС
- Package
- TSSOP-8
- Series
- Интерфейс - интерфейсы датчиков и детекторов
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8495ARMZ | AD8494ARMZ | Why it matters |
|---|---|---|---|
| Sensor Type | K-type thermocouple | J-type thermocouple | Determines which thermocouple the amplifier is calibrated for; using the wrong type causes large temperature measurement errors. |
| Output Voltage at 25°C (ambient) | 5 mV/°C (K-type, 41 µV/°C × 122) | 5 mV/°C (J-type, 52 µV/°C × 96) | Both provide a 5 mV/°C output, but the internal gain differs to match the respective thermocouple sensitivity, so the transfer function is tied to the sensor type. |
| Internal Gain | 122 V/V | 96 V/V | The gain is factory-trimmed to the thermocouple's Seebeck coefficient; substituting one for the other without accounting for gain yields incorrect readings. |
| Thermocouple Sensitivity Assumed | 41 µV/°C (K-type) | 52 µV/°C (J-type) | The device linearizes around this nominal sensitivity; mismatch with the actual sensor degrades accuracy across the temperature range. |
| Temperature Range (specified) | 0°C to +50°C (reference junction compensation range) | 0°C to +50°C (reference junction compensation range) | Both share the same ambient compensation window, but usable thermocouple range and accuracy differ due to sensor type. |
| Supply Voltage Range | 2.7 V to 18 V (single supply) | 2.7 V to 18 V (single supply) | Identical supply flexibility allows either part to operate in the same power rail design. |
| Supply Current | ~180 µA typical | ~180 µA typical | Low, equal quiescent current suits battery-powered and low-power instrumentation in either case. |
| Package | 8-lead MSOP (RMZ) | 8-lead MSOP (RMZ) | Same footprint and pinout enable drop-in PCB compatibility between the two parts. |
| Operating Temperature Range | −40°C to +125°C | −40°C to +125°C | Identical industrial temperature rating means both suit the same environmental conditions. |
| Functional Substitutability | K-type thermocouple amplifier | J-type thermocouple amplifier | Despite identical package and supply, the parts are not functionally interchangeable because each is calibrated for a different thermocouple type. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8495ARMZ | AD8494ARMZ |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Part Status | Active | Active |
| Type | Thermocouple Amplifier | Thermocouple Amplifier |
| Input Type | Differential | Differential |
| Output Type | Analog | Analog |
| Supply Current | 250 µA | 250 µA |
| Operating Temperature | 0°C ~ 50°C | 0°C ~ 50°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What is the primary functional difference between the AD8495ARMZ and AD8494ARMZ?
The AD8495ARMZ is a thermocouple amplifier with a fixed gain of 122.4 V/V, optimized for K-type thermocouples with a 5 mV/°C output sensitivity. The AD8494ARMZ is a thermocouple amplifier with a fixed gain of 245 V/V, optimized for J-type thermocouples with a 10 mV/°C output sensitivity. Both are pin-compatible in the same 8-lead MSOP package but are calibrated for different thermocouple types.
Are the AD8495ARMZ and AD8494ARMZ pin-compatible?
Yes. Both devices are offered in the same 8-lead MSOP (RM) package with identical pin functions, including +VS, -VS, +IN, -IN, REF, OUT, and the offset/setpoint pins. This allows a common PCB footprint, but the surrounding circuit values and thermocouple type must be matched to the specific device.
Which thermocouple types do the AD8495ARMZ and AD8494ARMZ support?
The AD8495ARMZ is factory-trimmed for K-type thermocouples, providing a nominal output of 5 mV/°C. The AD8494ARMZ is factory-trimmed for J-type thermocouples, providing a nominal output of 10 mV/°C. Each device includes cold-junction compensation optimized for its respective thermocouple type.
What is the supply voltage range for the AD8495ARMZ and AD8494ARMZ?
Both devices operate from a single supply of 2.7 V to 18 V or a dual supply of ±2.7 V to ±18 V, per the Analog Devices datasheet. The output swing and reference pin configuration should be selected to keep the output within the amplifier's linear range for the expected thermocouple temperature range.
Can the AD8495ARMZ and AD8494ARMZ be used interchangeably in an existing design?
No, not without redesign. Although they share the same package and pinout, the gain (122.4 V/V for AD8495ARMZ vs. 245 V/V for AD8494ARMZ) and thermocouple calibration (K-type vs. J-type) differ. Substituting one for the other without adjusting the thermocouple type and output scaling will produce incorrect temperature readings.
What is the output voltage sensitivity of each device?
The AD8495ARMZ provides a nominal output sensitivity of 5 mV/°C when used with a K-type thermocouple. The AD8494ARMZ provides a nominal output sensitivity of 10 mV/°C when used with a J-type thermocouple. These sensitivities are set by the internal fixed gain and the respective thermocouple Seebeck coefficient.
Do both devices include cold-junction compensation?
Yes. Both the AD8495ARMZ and AD8494ARMZ integrate cold-junction compensation circuitry on-chip, eliminating the need for an external temperature sensor and compensation network. The compensation is trimmed for the specific thermocouple type of each device (K-type for AD8495ARMZ, J-type for AD8494ARMZ).
What is the operating temperature range for the AD8495ARMZ and AD8494ARMZ?
Both devices are specified for the industrial temperature range of −40°C to +125°C, per the Analog Devices datasheet. The usable measurement range also depends on the thermocouple type, supply voltage, and output reference configuration.