OPA134PA - 8MHz FET Audio Op Amp | Texas Instruments
부품 번호: OPA134PA ✓ 활성OPA134PA 개요
An operational amplifier is a high-gain differential amplifier used in feedback configurations to amplify or process analog signals. The OPA134PA belongs to the SoundPlus family of audio operational amplifiers, a category optimized for low distortion, low noise, wide bandwidth, and strong output-drive capability. Its FET-input architecture replaces the input-bias current characteristic commonly associated with bipolar transistor input stages. In practical audio systems, this helps reduce source-dependent distortion and allows the amplifier to work effectively with high-impedance sensors, transducers, and low-level pickup stages.
The OPA134PA provides 8 MHz gain-bandwidth product and 20 V/µs slew rate, supporting accurate reproduction of rapidly changing audio waveforms without requiring a bipolar input device. Its 8 nV/√Hz noise density is valuable when the op amp follows a low-level source, because the amplifier adds less noise to the signal being amplified. The manufacturer identifies the device as a true FET-input amplifier, while the distributed specifications indicate an input bias current of 50 pA, supporting low-level and high-impedance applications where bias-current-induced errors would otherwise become significant.
Audio performance is the central technical advantage. The specified distortion of 0.00008% is exceptionally low for a general-purpose audio preamplifier, while the high open-loop gain of 600 provides useful gain-bandwidth and precision characteristics in closed-loop amplifier networks. Wide supply operation extending to ±18 V gives designers room to use conventional dual-rail audio supplies and to build higher-amplitude stages around the amplifier. The 8-pin PDIP package also supports conventional through-hole assembly rather than requiring a fine-pitch surface-mount process.
Typical uses include stereo and mono audio preamplifiers, active low-pass and high-pass filters, microphone and instrumentation preamplifiers, line-level buffers, and headphone-amplifier signal paths. In a feedback stage, the closed-loop gain is established primarily by external resistors, while the op amp must remain stable with the selected feedback network and load. For driving long or highly capacitive cables, source impedance, output-current demand, and stability should be checked before the circuit is finalized.
A critical layout practice is to keep the input and feedback components close to the associated pins. Short feedback-loop traces reduce parasitic feedback and help preserve phase margin. Power-supply bypassing should be placed at the device pins, and unused supply pins must follow the manufacturer’s connection guidance. Output loads should remain within the device’s rated operating conditions, particularly when driving transformers, long cables, or capacitive stages.
This page combines the manufacturer’s device description with searchable OPA134PA pinout, datasheet, and PDF queries, practical audio-circuit guidance, lifecycle information, and a parameter-by-parameter framework for evaluating replacement choices. It also distinguishes confirmed drop-in replacements from functional substitutes so engineers can preserve the original 8-pin PDIP footprint before committing a redesign.
드롭인 대체품: OPA134PA — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 제품에는 사용 가능한 드롭인 대체품이 없습니다.
대체품 요청OPA134PA 최대 정격 & 전기적 특성
| Operational Amplifier Type | Single high-performance audio operational amplifier |
| Channel Count | 1 circuit |
| Gain-Bandwidth Product | 8 MHz |
| Input Bias Current | 50 pA |
| Input Noise Density | 8 nV/√Hz |
| Total Harmonic Distortion | 0.00008% |
| Slew Rate | 20 V/µs |
| Open-Loop Gain | 600 |
| Supply Voltage Range | ±18 V |
| Input Stage | True FET input |
| Product Family | SoundPlus high-performance audio operational amplifier |
| 패키지 | 8-pin PDIP |
| 실장 유형 | Through-hole |
OPA134PA 8-pin pdip 핀 구성 가이드
OPA134PA(8-pin pdip 패키지)의 핀 구성입니다. 이 아날로그 부품에는 입력, 출력, 전원 공급 핀이 있습니다. 오프셋 널, 보상, 인에이블 핀 구성은 제조사 데이터시트를 참조하십시오. 신호 컨디셔닝 및 증폭기 회로에 이상적입니다.
다음에 대한 상세 핀아웃 데이터 없음: OPA134PA.
다음을 참조하십시오: 데이터시트 전체 핀 구성은 다음을 참조하십시오.
일반적인 애플리케이션
OPA134PA 적합 용도: 6 애플리케이션s: Low-Level Audio Preamplifier, Active Audio Filter, Headphone Driver Signal Stage, Line-Level Audio Buffer, Instrumentation Preamp, Professional Audio Mixer Input.
Low-Level Audio Preamplifier
The OPA134PA fits low-level audio preamplification because its true FET input and 50 pA input bias current reduce the likelihood that the amplifier itself will impose significant bias-current error on high-impedance sources. Its 8 nV/√Hz noise density keeps added noise low relative to weak microphone, pickup, or instrument signals, while the 0.00008% distortion specification supports clean amplification. The stage can use conventional inverting or non-inverting feedback topology, with external resistors setting the closed-loop gain. Designers should keep the input and feedback paths short, select low-noise resistor networks, and confirm that the selected load remains within the output-drive limits stated in the manufacturer datasheet.
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Active Audio Filter
The OPA134PA is suitable for active audio filtering because its 8 MHz gain-bandwidth product and 20 V/µs slew rate provide margin above the audio band and help preserve phase and transient behavior. Low distortion of 0.00008% is especially useful in crossover, equalization, and noise-shaping networks where added harmonic content would be objectionable. A practical implementation places the resistor and capacitor network around the amplifier and keeps the feedback loop compact. The actual usable bandwidth and stability depend on gain, component tolerances, source impedance, and loading, so evaluate the final topology across the intended frequency range rather than relying only on the 8 MHz headline value.
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Headphone Driver Signal Stage
OPA134PA can serve as a voltage-gain and signal-conditioning stage ahead of a headphone output amplifier when the system is designed around the amplifier’s 20 V/µs slew rate and low distortion. The 8 MHz bandwidth provides headroom for transient-rich audio content, and the true FET input avoids the bias-current behavior of a bipolar-input amplifier. In a practical implementation, the OPA134PA drives a higher-current output stage rather than directly driving low-ohm headphones. Source and feedback impedances should be balanced carefully, and output loading, cable capacitance, supply headroom, and thermal conditions should be checked to prevent instability or distortion.
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Line-Level Audio Buffer
OPA134PA works well as a line-level buffer when preserving signal integrity and providing stronger drive are more important than minimal generic-op-amp cost. Its 8 nV/√Hz noise density contributes little noise to a nominal line-level source, while its high open-loop gain of 600 and low distortion help maintain accurate transfer through the feedback network. The wide supply capability supports conventional dual-rail audio architecture. Use a unity-gain voltage follower only where stability is assured; otherwise a modest noise gain can improve loop behavior. Keep the output path short, observe grounding practices, and verify the connected cable or next-stage capacitance against the amplifier’s stability requirements.
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Instrumentation Preamp
OPA134PA is appropriate for a low-level instrumentation preamp when low input bias current and low noise are valuable. The 50 pA bias-current characteristic is especially useful with high-impedance sensors, while 8 nV/√Hz noise density minimizes voltage-noise contribution. Its 0.00008% distortion and 8 MHz bandwidth support accurate signal conditioning across a broad range of source impedances and frequencies. The circuit should use a defined reference arrangement for single-ended inputs, low-value low-noise feedback resistors where appropriate, and guarding to reduce leakage on high-impedance nodes. Supply bypassing and grounding are especially important because they can otherwise set the practical noise floor of the measurement chain.
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Professional Audio Mixer Input
OPA134PA can provide low-distortion gain and impedance conversion in a professional audio mixer input module. Its true FET input helps maintain signal integrity with microphone and line sources, while the low noise density is advantageous when the input works close to the noise floor. The 20 V/µs slew rate supports clean handling of transient peaks, and the 0.00008% distortion specification reduces harmonic coloration in the first gain stages. Use the lowest practical closed-loop gain that still provides the required signal swing, maintain predictable source impedances, and keep sensitive input routing away from power converters and high-current output stages.
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추천 제품 요약
엔지니어링 참조 데이터: OPA134PA — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 |
|---|---|
| Package | 8-pin PDIP |
| Brand | Texas Instruments |
| Amplifier Configuration | Single |
| Gain-Bandwidth Product | 8 MHz |
| Input Noise Density | 8 nV/√Hz |
| Input Bias Current | 50 pA |
| Slew Rate | 20 V/µs |
| Distortion | 0.00008% |
| Open-Loop Gain | 600 |
| Supply Voltage Range | Up to ±18 V |
주요 차별점
- True FET input preserves low-bias-current audio behavior (vs TL071)
- Higher bandwidth and slew rate for transient-rich audio (vs TL071)
- Lower specified distortion for high-fidelity signal paths (vs TL071)
설계 노트
Place the input, feedback, and decoupling components close to their corresponding OPA134PA pins. Keep the feedback path short and avoid routing input traces beside power converters, relay contacts, or high-current output stages. For high-impedance sources, minimize leakage paths and guard sensitive nodes where practical. The 50 pA input bias current makes the amplifier suitable for FET-style sensing circuits, but board contamination and flux residue can still create errors that are much larger than the specified bias current.
Do not assume that any 8-pin audio amplifier is a drop-in replacement for the OPA134PA. The replacement must preserve the PDIP-8 footprint and pin functions while providing compatible input bias current, noise, bandwidth, slew rate, distortion, common-mode range, and supply limits. A dual amplifier such as OPA2134 has unused channels and a different pin arrangement, so it can require PCB changes even though it belongs to the same product family.
Use the manufacturer’s supply-pin connection and decoupling guidance for the OPA134PA. Place the supply-bypass capacitor directly between the appropriate power pin and ground, with a short ground return. The device supports supply rails extending to ±18 V, but allowable total voltage and common-mode limits must be respected. In dual-rail audio circuits, account for startup behavior, output headroom, and any ground offset at the signal source instead of assuming a zero-volt midpoint is always available.
Evaluate closed-loop stability with the actual source impedance, feedback network, and load. The 8 MHz gain-bandwidth product and 20 V/µs slew rate support wide-band audio work, but long feedback traces, cable capacitance, transformer loading, or excessive noise gain can alter phase margin. If driving a difficult load, add an appropriate isolation resistor or buffer and confirm performance with oscilloscope measurements at the output rather than relying only on the nominal gain-bandwidth specification.
규정 준수 정보
No explicit compliance declarations for the exact OPA134PA ordering option were identified in the referenced manufacturer and distributor pages.