OPA604AP - FET Audio Op Amp | Texas Instruments
料号： OPA604AP ✓ 量产中OPA604AP 概述
An operational amplifier is a voltage-gain, active-feedback component that compares an input signal with a feedback network and drives its output to reduce the difference between them. Operational amplifiers belong to the broader amplifier IC and analog signal-conditioning hierarchy. FET-input amplifiers use field-effect transistors at the input, supporting low input bias current and effective operation with high-impedance sources.
The OPA604AP is intended for applications where low distortion, low noise, wide bandwidth, and high dynamic range are more important than minimum power consumption. Key benefits include low-distortion operation at 1 kHz, 10 nV/sqrt(Hz) noise density, 20 MHz gain-bandwidth product, and unity-gain stability. These characteristics support precise signal amplification, active filtering, and current-to-voltage conversion without adding substantial distortion.
Its wide supply range accommodates conventional bipolar audio rails, higher-voltage analog systems, and lower-voltage designs. The low-noise FET input maintains wide dynamic range even when driven from a high source impedance. Laser-trimmed offset voltage is also used to reduce the need for interstage coupling capacitors, making the amplifier easier to deploy in straightforward audio signal paths.
Typical uses include professional audio equipment, PCM digital-to-analog converter current-to-voltage conversion, spectral-analysis instrumentation, active crossover networks, line-level preamplifiers, and precision test equipment. The combination of low noise and low distortion is particularly useful where small signal details must remain intelligible at the output.
Designers should preserve adequate output headroom, verify the common-mode range across the complete signal excursion, and place input and feedback components close to the device to minimize parasitic feedback. The through-hole package also requires adequate spacing for a stable breadboard or through-hole layout rather than a compact surface-mount assembly.
This product page combines manufacturer specifications, application guidance, pin information, and replacement considerations into an engineering-focused reference. It is designed to support circuit planning, source selection, and PCB design for low-noise audio and precision analog systems.
直接替换替代料： OPA604AP ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： OPA604AP （相同外形与封装尺寸） ——差异在于 Amplifier Type, Number of Circuits, Slew Rate, Supply Voltage Range, Unity-Gain Bandwidth.
OPA2604AP
✅ 直接替换📋 参考替代料（不在目录中）
OPA604AP 最大额定值与电气特性
| Amplifier Type | Single-circuit operational amplifier |
| Input Transistor Type | FET |
| Unity-Gain Bandwidth | 20 MHz |
| Slew Rate | 25 V/us |
| Input Noise Density | 10 nV/sqrt(Hz) |
| Maximum Total Supply Voltage | 48 V |
| Supply Voltage Range | 5 V to 48 V total |
| Maximum Symmetric Supply | ±24 V |
| Gain Stability | Unity-gain stable |
| 工作温度范围 | -25 C to +85 C |
| 封装 | 8-pin plastic mini-DIP |
| 安装类型 | Through-hole |
| Offset Voltage | Laser-trimmed |
| Distortion | Low at 1 kHz |
| Number of Circuits | 1 circuit |
| RoHS 状态 | unknown |
| REACH Status | unknown |
OPA604AP 引脚配置
| 引脚 1 | NULL — Offset null terminal |
| 引脚 2 | IN- — Inverting input |
| 引脚 3 | IN+ — Non-inverting input |
| 引脚 4 | V- — Negative supply connection |
| 引脚 5 | NULL — Offset null terminal |
| 引脚 6 | OUT — Output |
| 引脚 7 | V+ — Positive supply connection |
| 引脚 8 | NC — Not connected |
典型应用
OPA604AP 适用于 6 应用s: PCM DAC Current-to-Voltage Conversion, Professional Audio Preamplifier, Spectral Analysis Instrumentation, Active Crossover and Filter Network, Line-Level Buffer and Signal Conditioning, Precision Test and Measurement Front End.
PCM DAC Current-to-Voltage Conversion
The OPA604AP is well suited to converting the differential current output of a PCM DAC into a ground-referenced voltage. Its FET input supports high-impedance summing junctions, while the 20 MHz unity-gain bandwidth and 25 V/us slew rate provide margin for full-scale audio signals. According to the manufacturer, the amplifier is unity-gain stable and intended for PCM DAC I/V conversion. The feedback network should be selected around the converter’s compliance range, output capacitance, and target full-scale voltage. Confirm DAC settling behavior across the operating bandwidth and check the amplifier’s output swing before accepting the audio path.
推荐
Professional Audio Preamplifier
OPA604AP provides the low-noise, high-dynamic-range input stage needed in professional audio preamplifiers. Its 10 nV/sqrt(Hz) input noise supports quiet amplification of microphone- or line-level signals, and the 25 V/us slew rate reduces slew-related distortion in fast transients. The wide ±24 V capability accommodates traditional studio power rails. Choose resistor values that preserve signal headroom and keep the gain-bandwidth product high enough for the intended audio bandwidth. The FET input also suits high-impedance sources, but the source impedance should be checked against the complete noise and bias-current specification.
推荐
Spectral Analysis Instrumentation
The OPA604AP can condition low-level signals in spectral-analysis equipment where noise and distortion limit measurement fidelity. Its low 10 nV/sqrt(Hz) input noise preserves small-signal information, while the 20 MHz unity-gain bandwidth covers a substantially wider range than conventional audio amplifiers. Unity-gain stability permits direct use as a buffer when impedance conversion is required. Layout must minimize leakage and ground-loop contributions around the sensitive input node, and the gain structure should avoid amplifying noise outside the instrument’s measurement bandwidth.
推荐
Active Crossover and Filter Network
OPA604AP is suitable for active crossover and audio filter networks that require low distortion across several audio decades. The 20 MHz unity-gain bandwidth and 25 V/us slew rate provide ample loop-gain margin compared with typical 20 kHz audio crossover bands, while the FET input avoids excessive loading on preceding filter stages. Select Q, gain, and component tolerances to control phase and cutoff accuracy. Check every filter stage for stable operation at the closed-loop gain selected, because compensation limits and output drive can alter the usable topology.
推荐
Line-Level Buffer and Signal Conditioning
OPA604AP can serve as a high-impedance buffer between a source and a balanced audio output stage. Unity-gain stability supports direct follower operation, and the low-noise FET input preserves source detail when the preceding circuit has high output impedance. The 25 V/us slew rate helps maintain low distortion through rapidly changing music signals. Keep the buffer input path short, avoid placing high-impedance nodes near switching nodes, and confirm that the destination can be driven through the amplifier’s output-current and capacitive-load limits.
推荐
Precision Test and Measurement Front End
OPA604AP is useful in laboratory front ends that require low-noise amplification without sacrificing bandwidth or transient response. The 10 nV/sqrt(Hz) input noise density supports measurement of small analog signals, and the 20 MHz unity-gain bandwidth allows the amplifier to operate beyond audio-band requirements. It can also buffer high-impedance detectors or sensors before an ADC. Verify input bias current, input offset voltage, common-mode range, and output current against the source and ADC interface, then use guarding or shielding techniques where leakage could affect the measurement.
推荐
推荐产品汇总
工程参考数据： OPA604AP ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | OPA2604AP | OPA134PA |
|---|---|---|---|
| Package | 8-pin plastic mini-DIP | 8-pin plastic mini-DIP | 8-pin plastic mini-DIP |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Input Type | FET | FET | FET |
| Primary Application | Low-distortion audio and wide-bandwidth analog signal amplification | Low-distortion FET-input audio amplification | FET-input audio amplification |
关键差异点
- High bandwidth and slew rate for low-distortion audio （对比 OPA134PA)
- Designed specifically for enhanced AC performance （对比 OPA2604AP)
- Wide high-voltage operating capability （对比 OPA134PA)
设计说明
Route the OPA604AP input and feedback paths away from clock, switching-regulator, and digital-signal traces. Keep the non-inverting input node as short as practical, use a quiet ground reference, and place feedback resistors close to pins 2 and 6. On a through-hole design, avoid long exposed input leads that can act as antennas and increase noise pickup.
Use a low-noise supply and decouple each supply pin locally with a stable ceramic capacitor plus an appropriate bulk capacitor. The manufacturer permits operation up to ±24 V, but usable output swing is lower because of headroom limitations. Verify the actual output waveform across input and load conditions, and include additional filtering if the supply contains switching ripple.
Do not treat an 8-pin DIP amplifier as interchangeable solely because another part also has eight pins. Confirm offset-null locations, supply pins, input polarity, output pin, and stability in the manufacturer pin table. Also check the alternative’s input offset voltage, bias current, common-mode range, and gain-bandwidth product before modifying a validated audio circuit.
For PCM DAC current-to-voltage conversion, account for parasitic capacitance at the summing node and verify converter settling time. Place the I/V feedback network close to the amplifier and DAC output, and probe the node with a low-capacitance instrument. If the circuit is unstable or exhibits peaking, reduce loop gain or add compensation only after checking the DAC datasheet’s recommended configuration.
合规信息
The accessible manufacturer product information does not state the requested compliance statuses. Use the Texas Instruments product page and current manufacturer documentation for procurement-specific declarations.
