Part A
AD8479ARZ
아날로그 디바이스(주)
- Lifecycle
- Active
- Stock
- 1516 PCS
- Package
- SOIC-8
- Series
- 선형 증폭기 - 계측기, 연산 증폭기, 완충 증폭기
Replacement verdict
Not a drop-in replacement
The AD8479ARZ and AD847AR-REEL are not drop-in replacements for one another. The AD8479ARZ is a precision high common-mode voltage difference amplifier, while the AD847AR-REEL is a high-speed low-power operational amplifier; they differ in amplifier topology, input voltage range, gain configuration, and bandwidth, so substituting one for the other requires circuit redesign and validation.
Different amplifier topology
Different input voltage range
Different gain configuration
Different bandwidth
Parts at a glance
Part B
AD847AR-REEL
아날로그 디바이스(주)
- Lifecycle
- Active
- Stock
- 3128 PCS
- Package
- SOIC-8
- Series
- 선형 증폭기 - 계측기, 연산 증폭기, 완충 증폭기
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8479ARZ | AD847AR-REEL | Why it matters |
|---|---|---|---|
| Amplifier Type | Difference Amplifier | Voltage Feedback Amplifier | The two parts serve fundamentally different functions; a difference amplifier extracts a differential signal, while a voltage feedback op amp is a general-purpose building block, so they are not direct substitutes. |
| Number of Circuits | 1 | 1 | Both are single-channel devices, so channel count does not differentiate them for substitution purposes. |
| Gain Bandwidth Product | Not specified (fixed gain of 1) | 50 MHz | The AD8479 has a fixed unity gain and no GBW spec, while the AD847 offers 50 MHz GBW for wideband signal processing; this affects achievable closed-loop bandwidth and high-frequency performance. |
| Slew Rate | Not specified | 300 V/µs | Slew rate limits large-signal transient response; the AD847's 300 V/µs supports fast, large-signal swings, whereas the AD8479 datasheet does not specify a comparable slew rate. |
| Input Offset Voltage | ±0.5 mV (typical) | ±0.5 mV (typical) | Offset voltage directly impacts DC accuracy; both parts offer similar typical offset, so DC precision is comparable. |
| Supply Voltage Range | ±5 V to ±18 V (dual) | ±4.5 V to ±18 V (dual) | The usable supply range determines compatibility with a given power rail; the AD8479 requires a slightly higher minimum dual supply than the AD847. |
| Input Common-Mode Voltage Range | ±600 V (high-voltage capable) | Limited to supply rails | The AD8479 is designed for high common-mode voltages up to ±600 V, while the AD847's common-mode range is bounded by its supplies; this is a critical difference for high-voltage sensing applications. |
| Operating Temperature Range | -40°C to +125°C | -40°C to +85°C | The wider temperature range of the AD8479 supports harsher environments, whereas the AD847 is limited to +85°C, affecting reliability in industrial or automotive use. |
| Package / Mounting Type | 8-SOIC (surface mount) | 8-SOIC (surface mount, tape and reel) | Both use the same 8-SOIC footprint, so board-level physical compatibility is maintained; the AD847AR-REEL is supplied in tape-and-reel for automated assembly. |
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 | AD8479ARZ | AD847AR-REEL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Part Status | Active | Obsolete |
| Amplifier Type | General Purpose | General Purpose |
| Number of Circuits | 1 | 1 |
| Slew Rate | 8V/µs | 300V/µs |
| Gain Bandwidth Product | - | 50 MHz |
| Current - Input Bias | - | 3.3 µA |
| Voltage - Input Offset | 500 µV | 500 µV |
| Supply Current | 550µA | 5.3mA |
| Current - Output / Channel | 55 mA | 32 mA |
| Voltage - Supply Span(Min) | 5 V | 9 V |
| Voltage - Supply Span(Max) | 36 V | 36 V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Output Type | Rail-to-Rail | - |
| -3 dB Bandwidth | 130 kHz | - |
Frequently asked questions
What are the fundamental differences between the AD8479ARZ and the AD847AR-REEL?
The AD8479ARZ is a high common-mode voltage difference amplifier designed to precisely measure signals with very high common-mode voltages (up to ±600 V), featuring a fixed gain of 1. The AD847AR-REEL is a high-speed, low-power operational amplifier with a 50 MHz gain-bandwidth product, packaged in an 8-lead SOIC and supplied on a reel. They are fundamentally different functional classes of devices and are not interchangeable.
Can the AD8479ARZ be used as a direct replacement for the AD847AR-REEL in an existing circuit?
No. The AD8479ARZ is a specialized difference amplifier with a fixed gain of 1 and internal precision resistors, while the AD847AR-REEL is a general-purpose voltage-feedback op-amp requiring external feedback components. Pin functions, internal architecture, and application topologies differ, so a direct substitution is not possible without a complete circuit redesign.
What are the package and ordering differences between the AD8479ARZ and the AD847AR-REEL?
The AD8479ARZ is supplied in an 8-lead SOIC package (R-8 suffix) in tube or tray quantities. The AD847AR-REEL is also supplied in an 8-lead SOIC package but is delivered on a tape-and-reel carrier for automated assembly. Both share the same SOIC footprint, but the "REEL" suffix denotes the packaging format, not a different die or performance grade.
Which device is suitable for high common-mode voltage sensing applications?
The AD8479ARZ is specifically designed for high common-mode voltage sensing, capable of withstanding up to ±600 V common-mode input while providing a precision differential output. The AD847AR-REEL is a standard op-amp with supply voltages typically limited to ±15 V and is not rated for high common-mode voltages, making it unsuitable for such applications.
How do the bandwidth and dynamic performance specifications compare?
The AD847AR-REEL offers a 50 MHz gain-bandwidth product and a slew rate of 300 V/µs, making it suitable for high-speed signal conditioning. The AD8479ARZ has a much lower bandwidth (typically 130 kHz) because it is optimized for precision high-voltage difference measurement rather than speed. The two devices target entirely different dynamic performance requirements.
Are the AD8479ARZ and AD847AR-REEL interchangeable in terms of supply voltage requirements?
No. The AD8479ARZ operates from dual supplies typically ranging from ±5 V to ±18 V and is designed to handle high common-mode voltages independent of its supply rails. The AD847AR-REEL operates from ±5 V to ±15 V dual supplies. While there is overlap in supply ranges, the AD8479ARZ's internal resistor network and high-voltage input architecture make it non-interchangeable with the AD847AR-REEL in supply-sensitive designs.
What is the significance of the "ARZ" and "AR-REEL" suffixes in the part numbers?
In the AD8479ARZ, "ARZ" denotes an 8-lead SOIC package with RoHS-compliant (Z) construction. In the AD847AR-REEL, "AR" denotes the 8-lead SOIC package and "REEL" indicates tape-and-reel packaging for high-volume automated assembly. The suffixes describe package and packaging attributes, not electrical performance grades.