LM2904ST Low-Power Dual Op Amp | STMicroelectronics
MPN： LM2904ST ✓ 啟用中LM2904ST 概覽
An operational amplifier is an active semiconductor device that compares two input voltages and drives its output to amplify the difference between them. In a closed-loop configuration, negative feedback causes the output to follow the intended circuit function with very high input impedance and relatively low output impedance. The LM2904 belongs to the operational-amplifier hierarchy, where it sits below precision amplifiers, rail-to-rail amplifiers, and high-speed amplifiers while remaining appropriate for industrial control, sensor conditioning, audio, and general instrumentation.
The LM2904ST provides two amplifier channels in one package, reducing component count and PCB space compared with two separate single-channel amplifiers. Its internally implemented frequency compensation simplifies circuit design by eliminating the need for external compensation components in standard closed-loop applications. Because both channels are independent, the device can support different signal paths, provided the designer observes the common power-supply and grounding requirements.
The target LM2904ST is a standard general-purpose dual amplifier in the MiniSO-8 format. The STMicroelectronics LM2904 family also includes other package and performance options, so engineers should compare electrical ratings, temperature range, supply limits, input common-mode range, output swing, and automotive qualification before treating another family member as a drop-in replacement. The exact electrical limits and environmental classifications should be confirmed in the manufacturer datasheet for the selected ordering code.
Typical uses include low-frequency sensor signal conditioning, control-loop amplification, active filtering, audio preamplification, transducer interfaces, and general buffer stages. In such circuits, the LM2904ST provides two independently usable channels while keeping the implementation compact. Its internal compensation makes conventional inverting, non-inverting, summing, and differential amplifier configurations straightforward, although output loading, source resistance, stability margins, and the input common-mode range still require careful review.
For a new layout, place the device close to the signals it processes, maintain a low-impedance return path to the supply ground, and decouple the supply pins locally. Avoid sensitive-source connections next to the output or supply pins, because parasitic coupling can increase offset and distortion. This product overview combines the manufacturer family information, package identity, pin assignment, sourcing considerations, and drop-in-replacement guidance to support faster engineering selection and PCB planning.
直接替換替代品，適用於 LM2904ST — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： LM2904ST （相同外形與佔位） — 差異在於 Amplifier Type, Mounting Type, Package.
LM2904YST
✅ 直接替換📋 參考替代品（不在目錄中）
LM2904ST 最大額定值與電氣特性
| Amplifier Type | General-purpose operational amplifier |
| Number of Channels | 2 channels |
| Number of Amplifiers | 2 amplifiers |
| Architecture | Two independent, internally frequency-compensated amplifiers |
| 輸出類型 | Single-ended |
| Power Class | Low-power operational amplifier |
| 封裝 | 8-pin MiniSO |
| 安裝類型 | Surface-mount |
LM2904ST 腳位配置
| 腳位 1 | OUT A — Output of amplifier A |
| 腳位 2 | -IN A — Inverting input of amplifier A |
| 腳位 3 | +IN A — Non-inverting input of amplifier A |
| 腳位 4 | V- — Negative supply or ground connection |
| 腳位 5 | +IN B — Non-inverting input of amplifier B |
| 腳位 6 | -IN B — Inverting input of amplifier B |
| 腳位 7 | OUT B — Output of amplifier B |
| 腳位 8 | V+ — Positive supply connection |
典型應用
LM2904ST 適用於 6 應用s: Industrial Sensor Signal Conditioning, Audio Preamplification, Active Filtering and Control Loops, Power-Supply Feedback and Monitoring, Data Acquisition and Instrumentation, Automotive and Robust Embedded Interfaces.
Industrial Sensor Signal Conditioning
The LM2904ST fits low-frequency sensor-conditioning stages where two independent channels can condition complementary or sequential signals. Each internal frequency-compensated amplifier can form an inverting, non-inverting, or differential stage while the MiniSO-8 package limits board footprint. Before selecting it, verify the sensor output range against the input common-mode limits, the required gain against the amplifier bandwidth, and the sensor-source impedance against input bias current. Place input components close to pins 2, 3, 5, and 6, route the quiet ground return directly to pin 4, and decouple pin 8 locally to minimize sensor noise coupling.
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Audio Preamplification
The LM2904ST is suitable for general-purpose, low-frequency audio preamplification when the required bandwidth, input impedance, output swing, and noise remain within the datasheet limits. Its two independent amplifier sections can support a stereo pair or provide two stages in a mono signal chain, while internal frequency compensation simplifies conventional feedback layouts. Use the non-inverting input pins as high-impedance summing nodes when gain is set with external resistors. Keep the layout quiet, maintain short feedback paths, and decouple the positive supply close to pin 8 so that output-current demand does not inject modulation into the audio input.
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Active Filtering and Control Loops
The LM2904ST can implement active filters and low-frequency control loops because each channel provides internally compensated, general-purpose amplification. Typical uses include second-order active-filter stages, error amplifiers, integrators, and summing networks. Component tolerances determine cutoff accuracy and closed-loop gain, so use suitable resistor and capacitor tolerances and check stability with the intended source and load impedances. Keep the feedback loop compact and isolate high-current switching nodes from the summing junction. When loop stability or settling behavior is critical, simulate the complete source impedance, load, and parasitic network rather than evaluating only the ideal amplifier equations.
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Power-Supply Feedback and Monitoring
The LM2904ST can assist with power-supply feedback, soft-start control, or analog monitoring when its supply and common-mode limitations suit the operating point. One channel may amplify a scaled feedback signal, while the other can provide an error or comparison function around a reference. This use requires careful treatment of the voltage range at pins 2, 3, 6, and 7; the output must also remain within the allowed swing for the chosen supply. Keep the feedback divider adjacent to the regulator output, avoid routing feedback beside switching power paths, and use local supply bypassing to prevent logic or converter transients from disturbing the control loop.
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Data Acquisition and Instrumentation
The LM2904ST is applicable to low-speed instrumentation buffers, amplifier chains, and interface circuits that benefit from two channels in one compact package. Independent channels can buffer two inputs, form a gain stage plus an output driver, or amplify differential and reference signals in a multi-rail instrument. Check input offset voltage, bias current, input noise, common-mode range, and output-current capability against the required measurement accuracy and source impedance. Use a single low-impedance ground plane where appropriate, avoid placing sensitive input traces beside the supply pin, and verify that the selected amplifier bandwidth maintains the required settling time at the operating gain.
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Automotive and Robust Embedded Interfaces
The LM2904ST can be evaluated for embedded analog interfaces where a dual, low-power amplifier helps consolidate board space, provided the exact ordering-code grade satisfies the environmental and qualification requirements. Before deploying it in an automotive product, confirm the operating temperature range, supply limits, ESD behavior, and AEC-Q100 status from the manufacturer documentation rather than assuming that every LM2904 suffix has the same qualification. Use stable reference and feedback networks, protect externally accessible inputs as required, and validate transient immunity at the system level. The small MiniSO-8 footprint is useful in dense controllers, but layout isolation remains essential.
推薦
推薦產品摘要
工程參考資料，適用於 LM2904ST — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | LM2904YST |
|---|---|---|
| Package | 8-pin MiniSO | 8-pin MiniSO |
| Brand | STMicroelectronics | STMicroelectronics |
| Amplifier Configuration | Dual operational amplifier | Dual operational amplifier |
| Number of Channels | 2 channels | 2 channels |
| Compensation | Internal frequency compensation | Internal frequency compensation |
| Power Class | Low-power | Low-power |
主要差異化特點
- Two independent amplifier channels in one compact package (對比LM2904YST)
- Internal frequency compensation (對比LM2904YST)
- Established general-purpose dual-amplifier positioning (對比LM2904YST)
設計說明
Place the local supply bypass capacitor immediately between pins 8 and 4, with the ground return terminating at the device ground pin rather than through a long peripheral path. Route the two non-inverting inputs and both inverting feedback networks away from the supply pin and outputs. Because the MiniSO-8 package is compact, preserve the manufacturer-recommended land pattern and verify courtyard clearance; do not substitute an SOIC-8 footprint on the assumption that all eight-pin packages are mechanically identical.
Do not assume that every device sold under the LM2904 family name has identical electrical or qualification ratings. Confirm the suffix-specific supply range, input common-mode limits, output swing, temperature grade, and AEC-Q100 status in the ordering table. When substituting LM2904YST, also verify pin functions and stability under the actual source resistance and load. A footprint match supports mechanical installation but does not by itself establish drop-in electrical equivalence.
Keep high-impedance input and feedback nodes short and protect them from capacitive coupling to output and supply pins. Place resistor networks close to their associated amplifier pins, use a continuous ground reference, and avoid long parallel routes next to switching nodes. For capacitive loads or high-gain layouts, include realistic source impedances and parasitic capacitance in simulation because internally compensated does not remove the need to verify the completed circuit’s stability.
Review output-current demand and voltage headroom before treating the amplifier as a general-purpose stage. The output must remain within the specified swing for the selected supply, and input signals must remain within the common-mode range. Place bulk and high-frequency bypass capacitance according to the power-source impedance and expected transient load. Verify that ground bounce and supply droop do not move either input outside its valid range, particularly in mixed-signal systems with digital switching activity.
合規資訊
The LM2904 family manufacturer datasheet and product page were identified, but the retrieved product information did not explicitly state the suffix-specific RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. Confirm these attributes for LM2904ST in the manufacturer's formal product documentation.
