OPA643U - 800MHz High-Gain Op Amp | Texas Instruments
部品番号: OPA643U ✓ 生産中OPA643U 概要
An operational amplifier is an analog integrated circuit that amplifies the voltage difference between its differential inputs. A voltage-feedback operational amplifier falls within the broader hierarchy of amplifier ICs, analog signal-chain ICs, and semiconductor devices. The OPA643U uses a de-compensated voltage-feedback architecture with two internal gain stages, allowing it to maintain high speed and dynamic range at relatively high closed-loop gains.
Key features include an 800 MHz gain-bandwidth product for high closed-loop bandwidth, a 1000 V/µs slew rate for rapid large-signal transitions, and 2.3 nV/√Hz input noise for sensitivity in wideband circuits. The device is stable in gains of 3 and above, which supports gain settings that are higher than those normally used with unity-gain-stable amplifiers. It is available in an 8-pin SOIC package.
The de-compensated architecture is important because it reserves performance for applications operating at higher closed-loop gains instead of simply providing maximum bandwidth near unity gain. However, feedback-network design remains critical: resistor and capacitor values, parasitic capacitance, and trace geometry can alter effective gain, peaking, and stability. Designers should follow the manufacturer datasheet for recommended gain and feedback arrangements rather than treating the amplifier as a unity-gain-stable part.
Typical applications include broadband analog filtering, video signal conditioning, communications receivers, instrumentation, and high-speed test-equipment input stages. It is particularly useful where the required signal bandwidth is high and the circuit operates with a closed-loop gain of at least 3. For applications involving ADC drivers, cable termination, or impedance-sensitive analog nodes, the complete signal path must be evaluated for noise, output drive, and parasitic effects.
A primary design consideration is stability at the intended gain and noise bandwidth. Keep feedback loops short, use the package ground and power pins as specified, and provide adequate high-frequency bypassing with low-inductance placement. The verified distributor excerpts identify the SOT23-5 package option for the device family, while OPA643U orderable-package information identifies an 8-pin SOIC package.
This page consolidates verified manufacturer and distributor excerpts, exact available parameters, sourcing links, application guidance, and engineering constraints. It also distinguishes documented OPA643U attributes from data that still requires confirmation from the complete datasheet or an authorized distributor before production release.
ドロップイン代替品: OPA643U — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: OPA643U （同一形状・フットプリント） — 相違点: Product Type.
この製品に利用可能なドロップイン代替品はありません。
代替品をリクエストOPA643U 最大定格＆電気的特性
| Product Type | Wideband low-distortion high-gain operational amplifier |
| Architecture | De-compensated voltage-feedback architecture with two internal gain stages |
| Gain-Bandwidth Product | 800 MHz |
| Slew Rate | 1000 V/µs |
| Input Voltage Noise | 2.3 nV/√Hz |
| Low-Distortion Frequency | 5 MHz |
| Minimum Stable Gain | 3 |
| OPA643U Package | 8-pin SOIC |
| Terminal Count | 8 terminals |
| Package Shape | Rectangular |
| Terminal Form | Gull wing |
| Temperature Grade | Industrial |
| 実装タイプ | Surface mount |
OPA643U rectangular ピン配置ガイド
OPA643U (rectangular パッケージ) のピン配置。 このアナログコンポーネントは、入力、出力、および電源ピンを備えています。オフセットナル、補償、イネーブルピンの設定については、メーカーのデータシートを参照してください。信号調整やアンプ回路に最適です。
詳細なピン配置データはありません: OPA643U.
詳細は データシート をご参照ください。
主な用途
OPA643U の用途: 6 件s: Broadband Active Filtering, Communications Receiver Front End, Video Signal Conditioning, High-Speed Instrumentation, Test and Measurement Input Stage, Data Acquisition Front End.
Broadband Active Filtering
The OPA643U fits active-filter stages requiring substantial bandwidth because its verified 800 MHz gain-bandwidth product and 1000 V/µs slew rate preserve signal amplitude and phase response beyond the range of many general-purpose amplifiers. Its de-compensated architecture is intended for closed-loop gains of 3 and above, allowing the feedback network to be selected for the target filter response. The 2.3 nV/√Hz input-noise specification also helps limit amplifier-generated noise in wideband signal paths. Designers should calculate component tolerances, verify the complete frequency-response simulation, and keep the feedback loop compact to avoid unintended peaking.
おすすめ
Communications Receiver Front End
OPA643U is suitable for communications receiver conditioning when the selected stage operates at a closed-loop gain of at least 3. Its 800 MHz gain-bandwidth product supports wideband signal paths, while the 1000 V/µs slew rate provides the transient response needed for high-amplitude, high-frequency waveforms. The verified 2.3 nV/√Hz input-noise figure helps engineers assess the amplifier's contribution to receiver sensitivity. In implementation, the input network must present a suitable impedance, grounding must follow the complete pin configuration, and filtering should preserve the intended passband without approaching an unverified stability region.
おすすめ
Video Signal Conditioning
OPA643U can be used in video and general high-speed signal-conditioning circuits where the 800 MHz gain-bandwidth product and 1000 V/µs slew rate are more important than low-cost or low-power operation. The verified datasheet excerpt specifically identifies low distortion at 5 MHz, making the part relevant to wideband video stages and related analog paths. Its de-compensated design requires attention to closed-loop gain and feedback-component selection. PCB layout should minimize loop area, maintain a continuous return path, and provide effective bypassing so that package and trace parasitics do not degrade rise time or introduce unintended frequency response.
おすすめ
High-Speed Instrumentation
OPA643U fits instrumentation preamplifier and buffer functions where measured signals may contain frequency content far above the audio range. Its 800 MHz gain-bandwidth product provides wide closed-loop bandwidth, and the 1000 V/µs slew rate limits large-signal distortion when the output must move rapidly. The 2.3 nV/√Hz input-noise specification provides a useful starting point for sensitivity calculations. The circuit still requires attention to source impedance, common-mode range, output swing, supply limits, and probe or sensor parasitics, none of which are fully available in the supplied search excerpts and must be confirmed from the complete datasheet.
おすすめ
Test and Measurement Input Stage
OPA643U is appropriate for high-speed test-equipment input stages that must handle rapid signal transitions with low distortion. The verified 800 MHz gain-bandwidth product supports wide operating bandwidth, while the 1000 V/µs slew rate helps maintain faithful large-signal response. Its specified low distortion at 5 MHz and 2.3 nV/√Hz input noise make it a candidate for precision broadband measurements. Designers should account for source termination, capacitive loading, stable feedback ratios, and connector or cable behavior. Complete validation requires the missing supply, offset, bias-current, common-mode, output-swing, and temperature-limit data from the full manufacturer datasheet.
おすすめ
Data Acquisition Front End
OPA643U can serve as a high-bandwidth gain stage ahead of an analog-to-digital converter when the acquisition path requires faster settling and broader signal support than a general-purpose amplifier provides. Its 800 MHz gain-bandwidth product and 1000 V/µs slew rate offer substantial dynamic range for rapidly changing input signals, and the 2.3 nV/√Hz noise specification is relevant to small-signal acquisition. The implementation must ensure that the ADC interface does not add excessive loading or sampling kickback, and that the selected closed-loop gain is at least 3. ADC drive requirements and timing should be verified independently because they are not included in the supplied excerpts.
おすすめ
エンジニアリング参考データ: OPA643U — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 |
|---|---|
| Product Type | Wideband low-distortion high-gain operational amplifier |
| Brand | Texas Instruments |
| Package | 8-pin SOIC |
| Gain-Bandwidth Product | 800 MHz |
| Slew Rate | 1000 V/µs |
| Input Noise Density | 2.3 nV/√Hz |
| Low-Distortion Frequency | 5 MHz |
| Minimum Stable Gain | 3 |
| Architecture | De-compensated voltage-feedback with two internal gain stages |
| Temperature Grade | Industrial |
主な差別化要因
- High bandwidth and slew rate in a single wideband amplifier （vs General-purpose lower-speed operational amplifiers)
- Designed for higher closed-loop gain operation （vs Unity-gain-stable operational amplifiers)
- Low input-noise density for a high-speed amplifier （vs Higher-noise general-purpose amplifiers)
設計ノート
Do not assume unity-gain stability for OPA643U. The verified Texas Instruments excerpts identify a de-compensated voltage-feedback architecture that is stable in gains of 3 and above. Use a closed-loop gain of at least 3 unless the complete application has been validated otherwise, and avoid copying a generic unity-gain feedback arrangement without evaluating frequency response and peaking.
Keep the feedback loop compact and route it directly between the amplifier output and inverting-input pins. Excessive loop area can introduce parasitic capacitance that changes the effective feedback factor, increases peaking, or reduces stability margin. Place bypass capacitors close to the relevant supply and ground pins using low-inductance layout techniques; exact pin numbers and bypass values must be confirmed from the complete OPA643 datasheet.
The 800 MHz gain-bandwidth product and 1000 V/µs slew rate make board-level parasitics significant even when the intended signal occupies a much narrower band. Maintain a continuous ground reference, avoid long high-impedance input routes, and account for source and load capacitance when selecting feedback resistors. Simulate the complete network with realistic probe, connector, and component parasitics before production release.
コンプライアンス情報
The supplied excerpts identify an industrial-grade amplifier but do not provide explicit RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals statements. AEC-Q100 is not applicable because this is an operational amplifier rather than an automotive-qualified device category.