OPA124P - 1pA Low-Noise Precision Op Amp | Texas Instruments
MPN： OPA124P ✓ 啟用中OPA124P 概覽
An operational amplifier, or op amp, is a high-gain differential amplifier used to amplify voltage differences in feedback-controlled circuits. The precision op-amp category combines low offset, low drift, high open-loop gain, and common-mode rejection with a wide range of input and output voltage limits. Within the broader semiconductor hierarchy, the OPA124P belongs to the precision analog amplifier family, where the primary design goal is accurate signal conditioning rather than maximum speed or lowest power consumption.
The OPA124P emphasizes measurement accuracy through a 1 pA maximum input bias current, 250 µV maximum input offset voltage, and 2 µV/°C maximum input voltage drift. Its 120 dB minimum open-loop gain and 100 dB minimum common-mode rejection ratio reduce errors in high-impedance instrumentation. The 10 V to 36 V operating supply range is compatible with split ±5 V to ±18 V laboratory rails, while the -5 V to +18 V input common-mode range supports signals extending beyond ground in appropriately biased systems.
The amplifier uses a precision DiFET input stage and cascoded architecture to combine low noise with high input impedance and reduced flicker-noise susceptibility. Laser-trimmed thin-film resistors support low offset and low drift. Unlike many low-noise bipolar input amplifiers, the DiFET topology provides extremely low bias current, making the OPA124P useful where source resistance is high and amplifier input current could otherwise create unacceptable measurement errors.
Typical uses include low-level sensor amplification, precision instrumentation, laboratory measurement equipment, photodiode signal chains, and high-impedance buffer stages. The 1 pA maximum bias current is especially valuable with sources whose output impedance is high, while the 250 µV maximum offset and 2 µV/°C maximum drift support stable DC measurements. The external offset-adjustment pins add calibration flexibility when system-level offset must be trimmed.
When designing around the OPA124P, preserve adequate input and output common-mode range and verify settling performance for the selected gain and load. If the source impedance is high, account for input-bias-current error and capacitance, and keep sensitive input traces away from switching nodes. Offset trimming should follow the manufacturer circuit because external adjustment can change drift by approximately 0.3 µV/°C for each 100 µV of adjusted offset.
This product page consolidates verified manufacturer-datasheet characteristics, distributor pricing, package information, and narrowly filtered PDIP alternatives. It also distinguishes documented electrical limits from unresolved procurement details, helping engineers evaluate the OPA124P without treating a substitute as interchangeable unless its package, pinout, temperature grade, and key parameters have been checked.
直接替換替代品，適用於 OPA124P — 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。
OPA124PA
✅ 直接替換📋 參考替代品（不在目錄中）
OPA124PB
✅ 直接替換📋 參考替代品（不在目錄中）
OPA124P 最大額定值與電氣特性
| Amplifier Type | Precision low-noise operational amplifier |
| Number of Circuits | 1 circuit |
| Input Bias Current | 1 pA maximum |
| Input Offset Voltage | 250 µV maximum |
| Input Voltage Drift | 2 µV/°C maximum |
| Open-Loop Gain | 120 dB minimum |
| Common-Mode Rejection Ratio | 100 dB minimum |
| Supply Voltage Range | 10 V to 36 V |
| Split Supply Range | ±5 V to ±18 V |
| Input Common-Mode Range | -5 V to +18 V |
| Noise Characterization Frequency | 10 kHz |
| Offset Adjustment | External adjustment pins available |
| Package Type | 8-pin PDIP |
| Package Body Width | 0.300 inch (7.62 mm) |
| 腳位數 | 8 pins |
| Input Transistor Technology | Precision DiFET |
OPA124P 0.300 inch (7.62 mm) 腳位配置指南
OPA124P（0.300 inch (7.62 mm) 封裝）的腳位配置。 此類比元件具有輸入、輸出與電源腳位。偏移歸零、補償與致能腳位配置請參閱製造商資料表。適用於訊號調理與放大器電路。
無詳細腳位定義資料： OPA124P.
請參閱 資料表 以查看完整腳位配置。
典型應用
OPA124P 適用於 6 應用s: High-Impedance Sensor Amplification, Photodiode Signal Conditioning, Precision Laboratory Instrumentation, Low-Level Voltage Buffering, Precision Bridge and Sensor Front Ends, Low-Level Current-to-Voltage Conversion.
High-Impedance Sensor Amplification
The OPA124P fits high-impedance sensor interfaces because its input bias current is limited to 1 pA maximum, minimizing the voltage error produced across high source resistance. A 250 µV maximum offset and 2 µV/°C maximum drift also support stable DC amplification, while the 100 dB minimum common-mode rejection ratio helps suppress common-mode interference. The device can be configured as a non-inverting or inverting precision gain stage around its external offset-adjustment pins. Designers should still guard sensitive inputs, control surface leakage, and account for input capacitance when settling accuracy is critical.
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Photodiode Signal Conditioning
The OPA124P is appropriate for photodiode signal conditioning when low input current and low leakage are more important than high bandwidth. Its 1 pA maximum input bias current limits the error generated when the amplifier operates with a high-impedance photodiode, while the 120 dB minimum open-loop gain supports accurate closed-loop gain. The precision DiFET input stage and reduced susceptibility to flicker noise support low-level measurements. In practice, the designer must select the transimpedance feedback resistor and compensation capacitance carefully while observing the manufacturer's offset-adjustment circuit.
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Precision Laboratory Instrumentation
OPA124P is well matched to precision laboratory instrumentation operated from split supplies between ±5 V and ±18 V. Its 1 pA maximum bias current reduces interaction with high-impedance probes, while 250 µV maximum input offset and 2 µV/°C maximum drift support repeatable measurements over changing conditions. The 10 V to 36 V total supply specification provides compatibility with common laboratory rails. External offset adjustment can reduce system-level offset, but the manufacturer notes that trimming may change drift by approximately 0.3 µV/°C for every 100 µV adjusted, so calibration procedures should account for that effect.
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Low-Level Voltage Buffering
The OPA124P can buffer low-level voltages without imposing the substantial input-current error associated with many bipolar-input operational amplifiers. A 1 pA maximum bias current is especially useful when the source impedance is high, and the 120 dB minimum open-loop gain helps preserve signal accuracy in a unity-gain buffer. Its 250 µV maximum offset and 2 µV/°C maximum drift remain relevant for precision measurements rather than only signal amplitude. Verify output swing, load capacitance, and stability at the intended frequency, and use the PDIP offset pins only with the documented adjustment network.
推薦
Precision Bridge and Sensor Front Ends
OPA124P is suitable for bridge-based and resistive sensor front ends where leakage and offset can corrupt the measurement. The 1 pA maximum input bias current minimizes excitation-rail error, and the 100 dB minimum common-mode rejection ratio helps reject common-mode voltage in differential sensor systems. Its 250 µV maximum input offset and 2 µV/°C maximum drift are useful for dc bridge signals that require stable calibration. The 10 V to 36 V supply range supports split laboratory rails, but excitation voltage, output range, and input common-mode limits must remain within the complete manufacturer specifications.
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Low-Level Current-to-Voltage Conversion
OPA124P can support low-level transimpedance and current-to-voltage conversion when the source current is small and leakage would otherwise dominate the measurement. The 1 pA maximum input bias current provides a low noise floor for the input stage, while the 120 dB minimum open-loop gain and 100 dB minimum common-mode rejection aid accurate closed-loop performance. The 8-pin PDIP format provides access to the external offset-adjustment pins specified for this package. Feedback resistor selection, compensation, board cleanliness, and guarding remain essential to achieve results consistent with the low input-current capability.
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推薦產品摘要
工程參考資料，適用於 OPA124P — 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 | OPA124PA | OPA124PB |
|---|---|---|---|
| Package | 8-pin PDIP | 8-pin PDIP | 8-pin PDIP |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Number of Circuits | 1 circuit | 1 circuit | 1 circuit |
| Input Bias Current | 1 pA maximum | 1 pA maximum | 1 pA maximum |
| Input Offset Voltage | 250 µV maximum | 250 µV maximum | 250 µV maximum |
| Input Voltage Drift | 2 µV/°C maximum | 2 µV/°C maximum | 2 µV/°C maximum |
| Supply Voltage Range | 10 V to 36 V | 10 V to 36 V | 10 V to 36 V |
| Open-Loop Gain | 120 dB minimum | 120 dB minimum | 120 dB minimum |
| Common-Mode Rejection Ratio | 100 dB minimum | 100 dB minimum | 100 dB minimum |
| Offset Adjustment | External offset-adjustment pins available | External offset-adjustment pins available | External offset-adjustment pins available |
主要差異化特點
- Extremely low input bias current for precision high-impedance measurement (對比OPA124PA)
- Low offset and low drift for dc precision (對比OPA124PB)
- External offset adjustment is available in the PDIP package (對比OPA124PA)
- Precision DiFET input architecture avoids conventional bipolar input current (對比OPA124PB)
設計說明
Do not use the external offset pins as a generic calibration interface without following the manufacturer circuit. The verified OPA124 datasheet states that external trimming of the remaining offset can change drift by approximately 0.3 µV/°C for each 100 µV of adjusted offset. Record both initial offset and drift, keep the adjustment network mechanically stable, and include the effect in the instrument's calibration budget.
For high-impedance sources, use guarding, clean PCB surfaces, and short input traces to prevent leakage and stray capacitance from degrading the benefit of the OPA124P's 1 pA maximum bias current. Keep the input node away from switching nodes and power-converter inductors. The 8-pin PDIP package offers useful lead spacing, but the complete pin configuration and exposed thermal behavior are not reproduced in the supplied data and should be checked directly in the manufacturer drawing.
The verified supply range is 10 V to 36 V total, or ±5 V to ±18 V split, but that operating range does not guarantee unrestricted input and output swing at every supply voltage. Check the input common-mode range of -5 V to +18 V against the signal and the output-voltage limits against the intended load. Decoupling requirements and the effect of output loading should be taken from the complete OPA124 datasheet rather than assumed from the supply rating.
Although the OPA124P targets precision rather than high-speed amplification, feedback-network capacitance and source capacitance can still affect stability and settling. Use the manufacturer's recommended feedback topology and compensation values for the intended gain and load. If a faster amplifier is required, do not substitute it solely because it has a similar package; compare slew rate, gain-bandwidth product, input bias current, offset, drift, and common-mode limits together.
合規資訊
The supplied manufacturer and distributor snippets do not explicitly state RoHS, REACH, lead-free, halogen-free, conflict-minerals, or automotive qualification status. No compliance claim is inferred from the package or distributor listings.