Part A
AD820ARZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7301 Stückzahl
- Package
- SOIC-8
- Series
- Linear-Verstärker.Instrumentation, OP-Verstärker, Pufferverstärker
Replacement verdict
Not a drop-in replacement
The AD820ARZ and AD8205WHRZ-RL are not functionally interchangeable: the AD820ARZ is a general-purpose single operational amplifier in an SOIC-8 package, while the AD8205WHRZ-RL is a dedicated high-side current-sense amplifier in an SOIC-8 package with a fixed gain of 20 V/V and an extended automotive-grade temperature range. Their differing amplifier architecture, gain configuration, and qualification grades make direct substitution impractical without circuit redesign and validation.
Different amplifier function
Different gain configuration
Different input topology
Different qualification grade
Parts at a glance
Part B
AD8205WHRZ-RL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2216 Stückzahl
- Package
- SOIC-8
- Series
- Linear-Verstärker.Instrumentation, OP-Verstärker, Pufferverstärker
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD820ARZ | AD8205WHRZ-RL | Why it matters |
|---|---|---|---|
| Amplifier Type | Single, precision, low power JFET-input operational amplifier | Single-supply, bidirectional current sense amplifier | These are fundamentally different functional blocks; one is a general-purpose op-amp and the other is a dedicated current-sense amplifier, so they are not direct substitutes. |
| Number of Channels | 1 | 1 | Both are single-channel devices, so channel count alone does not differentiate them for substitution. |
| Supply Voltage Range | 4.5 V to 36 V (single supply); ±2.25 V to ±18 V (dual supply) | 4.5 V to 5.5 V | The AD820ARZ supports a much wider supply range, while the AD8205WHRZ-RL is limited to 5 V systems, affecting compatibility in a given circuit. |
| Input Offset Voltage (max) | 0.8 mV (typical 0.4 mV) | 2 mV | Lower offset voltage improves DC accuracy; the AD820ARZ offers tighter offset performance than the current-sense amplifier. |
| Gain Configuration | Open-loop (external feedback sets gain) | Fixed gain of 50 V/V | The AD820ARZ requires external resistors for gain, whereas the AD8205WHRZ-RL has a fixed internal gain, changing design flexibility and external component count. |
| Input Bias Current (typ) | 2 pA (JFET input) | Not applicable (current-sense topology) | Extremely low bias current makes the AD820ARZ suitable for high-impedance sensors, a characteristic not matched by the current-sense architecture. |
| Bandwidth | 1.9 MHz (gain of 1) | 100 kHz (fixed gain of 50) | Bandwidth determines the maximum signal frequency the amplifier can handle; the AD820ARZ is much faster for general signal conditioning. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +125 °C | The wider temperature range of the AD8205WHRZ-RL makes it better suited to harsh automotive/industrial environments. |
| Package | 8-lead SOIC | 8-lead SOIC | Both use the same 8-lead SOIC footprint, so board-level physical compatibility is maintained even though the functions differ. |
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 | AD820ARZ | AD8205WHRZ-RL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Series | - | Automotive |
| Part Status | Active | Active |
| Amplifier Type | J-FET | Differential |
| Number of Circuits | 1 | 1 |
| Slew Rate | 3V/µs | 0.5V/µs |
| -3 dB Bandwidth | 1.9 MHz | 50 kHz |
| Voltage - Input Offset | 400 µV | 2 mV |
| Supply Current | 700µA | 2.2mA |
| Voltage - Supply Span(Min) | 5 V | 4.5 V |
| Voltage - Supply Span(Max) | 36 V | 5.5 V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 150°C |
| Mounting Type | Surface Mount | Surface Mount |
| Output Type | Rail-to-Rail | - |
| Gain Bandwidth Product | 1.8 MHz | - |
| Current - Input Bias | 2 pA | - |
| Current - Output / Channel | 20 mA | - |
Frequently asked questions
What are the fundamental differences between the AD820ARZ and the AD8205WHRZ-RL?
The AD820ARZ is a single-channel, precision, low-power operational amplifier in an 8-lead SOIC package, while the AD8205WHRZ-RL is a single-supply, bidirectional current-sense amplifier in an 8-lead SOIC package. The AD820ARZ is a general-purpose op amp, whereas the AD8205WHRZ-RL is purpose-built for high-side current sensing with an integrated gain resistor network.
Can the AD820ARZ be used as a direct substitute for the AD8205WHRZ-RL in a current-sense application?
No. The AD820ARZ is a general-purpose operational amplifier and does not include the internal precision gain resistors or the dedicated current-sense architecture of the AD8205WHRZ-RL. Substitution would require external gain and level-shifting circuitry and would not meet the verified performance specifications of the AD8205WHRZ-RL without a complete redesign.
What are the supply voltage requirements for each device?
The AD820ARZ operates from a single supply of 5 V to 36 V or a dual supply of ±2.5 V to ±18 V. The AD8205WHRZ-RL operates from a single supply of 4.5 V to 5.5 V, as specified in its datasheet for the W-grade version.
How do the input offset voltage specifications compare?
The AD820ARZ specifies an input offset voltage of 1 mV maximum at 25°C. The AD8205WHRZ-RL specifies an input offset voltage of 1 mV maximum at 25°C for the W-grade. Both devices are precision-grade, but the AD8205WHRZ-RL offset is specified in the context of its fixed gain configuration.
What is the fixed gain of the AD8205WHRZ-RL, and does the AD820ARZ have a comparable fixed gain?
The AD8205WHRZ-RL has a factory-trimmed fixed gain of 20 V/V. The AD820ARZ is an open-loop operational amplifier and does not have a fixed gain; its gain is set by external feedback components.
Are the package and pinout of the AD820ARZ and AD8205WHRZ-RL compatible?
Both devices are offered in an 8-lead SOIC package, but their pin functions differ. The AD820ARZ uses the standard single op-amp pinout (offset null, inputs, supply, output). The AD8205WHRZ-RL uses a dedicated current-sense pinout with supply, ground, output, and input pins. They are not pin-compatible for direct replacement.
What are the operating temperature ranges for the AD820ARZ and AD8205WHRZ-RL?
The AD820ARZ is specified for the industrial temperature range of −40°C to +85°C. The AD8205WHRZ-RL is specified for the automotive temperature range of −40°C to +125°C, as indicated by the W-grade suffix.
Which device is better suited for high-side current sensing in automotive applications?
The AD8205WHRZ-RL is specifically designed for high-side current sensing with a fixed gain of 20 V/V, a common-mode input range that extends beyond the supply, and an automotive temperature range of −40°C to +125°C. The AD820ARZ is a general-purpose op amp and would require external circuitry to perform the same function, making the AD8205WHRZ-RL the appropriate choice for verified automotive current-sense designs.