Part A
ADA4891-2ARMZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 6456 PCS
- Series
- Amplificateurs linéaires - instruments, amplificateurs opérationnels, amplificateurs tampons
Replacement verdict
Compatible functional replacement candidate
The ADA4891-2ARMZ is a viable functional replacement candidate for the ADA4805-2ARMZ in many dual op-amp applications, sharing the same SOIC-8 package and dual-channel topology. However, designers must validate supply voltage headroom, bandwidth, and quiescent current trade-offs before committing to a drop-in substitution.
Package Type
High match
Channel Count
High match
Supply Voltage Range
Validation required
Gain Bandwidth Product
Validation required
Parts at a glance
Part B
ADA4805-2ARMZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 1854 PCS
- Package
- MSOP-8
- Series
- Amplificateurs linéaires - instruments, amplificateurs opérationnels, amplificateurs tampons
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADA4805-2ARMZ | ADA4891-2ARMZ | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 2 | 2 | Both are dual op-amps, so channel count is compatible for direct substitution in dual-channel designs. |
| Supply Voltage Range | 3 V to 10 V (±1.5 V to ±5 V) | 2.7 V to 11 V (±1.35 V to ±5.5 V) | The usable supply window determines whether the part can drop into an existing rail configuration without redesign. |
| -3 dB Bandwidth | 105 MHz | 240 MHz | Bandwidth sets the maximum signal frequency the amplifier can handle; the ADA4891-2 offers more than double the bandwidth. |
| Slew Rate | 160 V/µs | 170 V/µs | Slew rate limits large-signal transient response; similar values mean comparable behavior for fast edges. |
| Input Offset Voltage (Max) | 125 µV | 6 mV | Lower offset voltage improves DC accuracy; the ADA4805-2 is far more precise, which matters for precision signal chains. |
| Input Voltage Noise Density | 5.5 nV/√Hz | 9 nV/√Hz | Lower noise density yields better SNR in low-level signal applications; the ADA4805-2 is quieter. |
| Quiescent Current per Amplifier | 0.5 mA | 4.4 mA | Quiescent current drives power budget; the ADA4805-2 is significantly more power-efficient. |
| Output Current (Typical) | 60 mA | 125 mA | Output drive capability affects the ability to drive heavy loads; the ADA4891-2 can source/sink more current. |
| Package | 8-Lead MSOP | 8-Lead MSOP | Identical package and pinout allow physical drop-in replacement on the same PCB footprint. |
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 | ADA4891-2ARMZ | ADA4805-2ARMZ |
|---|---|---|
| Part Status | Active | Active |
| Amplifier Type | CMOS | Voltage Feedback |
| Number of Circuits | 2 | 2 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 210V/µs | 250V/µs |
| Gain Bandwidth Product | 105 MHz | - |
| -3 dB Bandwidth | 90 MHz | 120 MHz |
| Current - Input Bias | 2 pA | 550 nA |
| Voltage - Input Offset | 2.5 mV | 13 µV |
| Supply Current | 4.4mA (x2 Channels) | 570µA (x2 Channels) |
| Current - Output / Channel | 125 mA | 73 mA |
| Voltage - Supply Span(Min) | 2.7 V | 2.7 V |
| Voltage - Supply Span(Max) | 5.5 V | 10 V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the key differences between the ADA4805-2ARMZ and ADA4891-2ARMZ?
The ADA4805-2ARMZ is a low-power, low-noise, rail-to-rail output dual op amp with a 105 MHz gain bandwidth product and 160 V/µs slew rate, while the ADA4891-2ARMZ is a high-speed, low-distortion dual op amp with a 220 MHz gain bandwidth product and 170 V/µs slew rate. The ADA4805-2ARMZ is optimized for lower quiescent current (approximately 500 µA per amplifier), whereas the ADA4891-2ARMZ draws approximately 4.4 mA per amplifier for higher bandwidth and lower distortion performance.
Are the ADA4805-2ARMZ and ADA4891-2ARMZ pin-compatible?
Yes. Both devices are offered in the same 8-lead MSOP (RM) package with identical pinout assignments, allowing them to share the same PCB footprint. However, pin compatibility does not guarantee electrical interchangeability, so supply voltage, loading, and stability must be validated for the target design.
What are the supply voltage ranges for these two amplifiers?
The ADA4805-2ARMZ operates from a single supply of 3 V to 10 V or a dual supply of ±1.5 V to ±5 V. The ADA4891-2ARMZ operates from a single supply of 2.7 V to 11 V or a dual supply of ±1.35 V to ±5.5 V. Both are specified over the −40 °C to +125 °C industrial temperature range.
Which device is better suited for low-power portable applications?
The ADA4805-2ARMZ is better suited for low-power designs because its quiescent current is approximately 500 µA per amplifier, significantly lower than the approximately 4.4 mA per amplifier of the ADA4891-2ARMZ. The ADA4805-2ARMZ also offers a disable feature that can further reduce power consumption when the amplifier is not in use.
How do the noise specifications compare between the ADA4805-2ARMZ and ADA4891-2ARMZ?
The ADA4805-2ARMZ has a low input voltage noise density of approximately 5.5 nV/√Hz at 100 kHz, making it suitable for precision signal conditioning. The ADA4891-2ARMZ has a higher input voltage noise density of approximately 9 nV/√Hz at 1 MHz, but it compensates with higher bandwidth and lower distortion for high-speed signal chains.
Can the ADA4891-2ARMZ be used as a drop-in replacement for the ADA4805-2ARMZ in an existing design?
Not without validation. Although both share the same 8-lead MSOP package and pinout, the ADA4891-2ARMZ draws roughly nine times the quiescent current of the ADA4805-2ARMZ and has different bandwidth, noise, and distortion characteristics. The power budget, supply decoupling, feedback network, and stability compensation must be re-evaluated against the ADA4891-2ARMZ datasheet before substitution.
What are the typical applications for each amplifier?
The ADA4805-2ARMZ is typically used in low-power portable instrumentation, battery-powered signal conditioning, active filters, and precision data acquisition where low quiescent current and low noise are critical. The ADA4891-2ARMZ is typically used in high-speed signal processing, video and imaging front ends, ADC drivers, and communication systems where wide bandwidth and low distortion are prioritized.