OPA681P - Wideband Current-Feedback Op Amp | Texas Instruments
MPN: OPA681P ✗ End of Life| Qty | Unit Price | Extended |
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| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
OPA681P Overview
An operational amplifier is a DC-coupled active device that amplifies the difference between two input voltages while using negative feedback to control gain, bandwidth, and impedance. The OPA681P belongs to the current-feedback operational-amplifier family, within the broader analog-amplifier and semiconductor hierarchy. Current-feedback amplifiers derive their name from the way the inverting input and feedback network influence current rather than relying only on a fixed closed-loop voltage gain relationship. This architecture can preserve usable bandwidth at higher closed-loop gains than a conventional voltage-feedback amplifier.
The verified feature set emphasizes broadband performance rather than micropower operation. The OPA681 can operate from a single +5 V supply, is stable at unity gain, and provides a high-output-current stage with minimal voltage headroom and crossover distortion. Its 2100 V/µs slew rate makes large-amplitude signals possible at high frequencies, while the wide output swing helps preserve signal amplitude when driving downstream circuitry. The disable function allows the amplifier to be controlled in systems where shutdown or power-management behavior is needed.
The current-feedback topology is important for design selection. Because feedback resistance affects gain and bandwidth, the manufacturer datasheet and application guidance should be consulted for the intended closed-loop gain rather than treating the amplifier as a conventional voltage-feedback device. Layout should minimize parasitic capacitance, especially around high-speed input, feedback, and output nodes. Short, direct feedback traces and a carefully selected feedback resistor help preserve the advertised wideband behavior.
Typical uses include video and broadcast signal conditioning, instrumentation, active filters, data converters, communications interfaces, and other wideband analog systems. The device is particularly relevant when a design needs a single +5 V rail, unity-gain stability, high slew rate, and the ability to source or sink substantial output current. It is not a general-purpose low-noise precision amplifier and should not be selected solely from DC offset or low-frequency noise specifications.
The principal design trade-off is speed versus power and signal integrity. A 2100 V/µs slew rate requires short feedback paths, suitable terminations, controlled load capacitance, and careful grounding. Before layout release, verify the exact package pinout and all operating limits against the manufacturer datasheet, especially for external disable control and output loading.
This product page consolidates verified distributor identification, manufacturer-linked datasheet references, application context, and replacement constraints. It distinguishes electrically similar parts from true same-package drop-in alternatives and leaves unverified parameters explicitly marked rather than estimating them.
Drop-in alternatives for OPA681P — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
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Request AlternativesOPA681P Maximum Ratings & Electrical Characteristics
| Amplifier Type | Current-feedback operational amplifier |
| Number of Circuits | 1 circuit |
| Supply Operation | +5 V |
| Gain | Unity-gain stable |
| Slew Rate | 2100 V/µs |
| Output Voltage Swing | ±4.0 V |
| Output Current | 150 mA |
| Supply Current | 6 mA |
| Differential Gain Drift | 0.001%/°C |
| Disable Function | Yes |
| Package Type | 8-pin PDIP |
| Package Pins | 8 pins |
| Mounting Type | Through-hole |
| Product Type | Wideband operational amplifier |
| Manufacturer Description | SpeedPlus wideband current-feedback operational amplifier with disable |
| RoHS Compliance | unknown |
| REACH Compliance | unknown |
| AEC-Q100 Qualification | not_applicable |
OPA681P 8 pins Pin Configuration Guide
Pin configuration for OPA681P (8 pins package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for OPA681P.
Refer to the datasheet for full pin configuration.
Typical Applications
OPA681P is suitable for 7 applications: Video Signal Conditioning, Active Filter Stages, Data Converter Interface, Communications Signal Path, Test and Measurement Front End, Instrumentation Buffering, Power-Sequenced Analog Control.
Video Signal Conditioning
The OPA681P fits wideband video conditioning because it is unity-gain stable and provides a verified 2100 V/µs slew rate with 150 mA output-current capability. Place it as a buffer or low-gain amplifier between a video source and the next stage, using short feedback traces and controlled grounding. The +5 V supply and approximately ±4.0 V output swing are useful for single-supply systems, while the wideband architecture helps preserve signal amplitude at higher frequencies. Before finalizing the stage, verify input common-mode range, gain-bandwidth behavior, load capacitance, and the exact disable-pin state.
Recommended
Active Filter Stages
OPA681P can serve in an active filter when the filter stage requires high bandwidth and a strong output driver rather than primarily very low DC error. Its unity-gain stability and 2100 V/µs slew rate help preserve large-amplitude signals through fast filter transitions. Use the manufacturer’s current-feedback feedback guidance, keep the feedback component close to the amplifier, and account for parasitic capacitance introduced by the filter topology. Because the verified data does not provide complete noise or settling specifications, confirm them for low-frequency or precision filter requirements.
Recommended
Data Converter Interface
The OPA681P is applicable to interface buffering around wideband data-conversion systems when the analog output or input stage needs fast slew and strong drive. Its 150 mA output-current specification can reduce the burden on the source when driving a subsequent analog or termination network, while the 2100 V/µs slew rate helps reproduce fast transitions. The design must be compensated for the converter’s capacitive input or output behavior, and the amplifier’s output swing must be checked against the converter’s supply and signal range. Disable control can also be coordinated with converter power sequencing.
Recommended
Communications Signal Path
OPA681P is suitable for communications signal paths that require wideband amplification, low-latency response, and robust output drive. The verified current-feedback architecture, unity-gain stability, and 2100 V/µs slew rate make it more relevant to high-speed analog stages than to slow precision amplifiers. Use short traces between the amplifier, feedback network, and load, and provide a low-impedance return path to reduce susceptibility to digital and switching noise. Validate gain accuracy, bandwidth, output loading, and disable timing against the specific communications standard.
Recommended
Test and Measurement Front End
The OPA681P can be used in a high-speed test-and-measurement front end when the source impedance and load require more drive than a conventional precision op amp can provide. Its 150 mA output-current capability and 2100 V/µs slew rate support fast edge generation and acquisition paths, while the 8-pin PDIP package is convenient for through-hole prototyping. Keep the input and feedback loops short, use a stable reference or source network, and avoid relying on the amplifier for precision DC accuracy unless the missing offset, noise, and drift specifications are acceptable.
Recommended
Instrumentation Buffering
OPA681P can buffer instrumentation signals when the application values wideband response and output drive more than minimum DC precision. The unity-gain-stable configuration supports direct buffering, while the current-feedback implementation should be laid out with short feedback paths to preserve bandwidth. The verified +5 V operating description and approximately ±4.0 V output swing support single-supply instrumentation, but the input common-mode range, offset, noise, and bias-current values were not supplied. Confirm those specifications before using it for precision bridge or sensor measurements.
Recommended
Power-Sequenced Analog Control
The verified disable function makes OPA681P potentially useful in power-sequenced analog systems where an amplifier must be inactive during a controlled startup interval. Connect the disable control only after confirming its logic polarity and timing from the manufacturer datasheet, and ensure the powered-down output state is acceptable to the downstream load. The wideband output stage can preserve fast control-signal transitions, while the approximately 6 mA supply description helps with power-budget planning. Add local bypass capacitance and verify sequencing against every powered block.
Recommended
Engineering reference data for OPA681P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product |
|---|---|
| Device Type | Single current-feedback operational amplifier |
| Supply Operation | +5 V |
| Gain Stability | Unity-gain stable |
| Slew Rate | 2100 V/µs |
| Output Current | 150 mA |
| Output Voltage Swing | ±4.0 V |
| Supply Current | 6 mA |
| Disable Function | Yes |
| Package | 8-pin PDIP |
| Brand | Texas Instruments |
Key Differentiators
- Current-feedback architecture with high slew rate (vs OPA658U/2K5)
- Single-supply-oriented operation (vs OPA681)
- Disable capability (vs OPA681)
Design Notes
Current-feedback amplifiers are sensitive to feedback-loop parasitics. Route the OPA681P feedback resistor and return path as short as practical, avoid routing beneath the package where supported by the PCB process, and keep the output path separated from sensitive high-impedance input nodes. Place input and feedback components close to the relevant pins. Do not copy a voltage-feedback layout without checking the manufacturer’s current-feedback guidance.
Design the supply network for the verified +5 V operating condition and validate every pin against the manufacturer datasheet before energizing the board. Place local bypass capacitance close to the power pins and use a low-impedance ground return for the output and feedback current. The verified approximately 6 mA supply current is useful for budget planning, but it does not by itself define total power dissipation, startup current, or the behavior during disable transitions.
Do not treat OPA681P as a generic voltage-feedback op amp or assume that every resistor value produces the same gain and bandwidth. Confirm the exact pinout, disable polarity, input common-mode range, output swing, and load limitations from the manufacturer datasheet. The 2100 V/µs slew rate can expose inadequate grounding, excessive capacitive loading, or long feedback traces as overshoot and ringing. Validate with a realistic source and load rather than an ideal simulation only.
Compliance Information
The verified data identifies the device as an older Burr-Brown/Texas Instruments operational amplifier but does not provide explicit RoHS, REACH, lead-free, halogen-free, conflict-minerals, or automotive qualification statements. Compliance fields are therefore unknown rather than assumed.