INA115AU - 1MHz Precision Instrumentation Amplifier | Texas Instruments
MPN： INA115AU ✓ 啟用中INA115AU 概覽
An instrumentation amplifier is a specialized amplifier category optimized for measuring a differential voltage superimposed on a larger common-mode voltage. Its internal three-op-amp topology provides high input impedance, accurate differential gain, and strong common-mode rejection. Within the broader hierarchy, an instrumentation amplifier is an analog amplifier, an analog integrated circuit, and ultimately a semiconductor designed for precision signal conditioning.
The INA115AU combines switched gain operation, low input offset voltage, low drift, and low input bias current. Its specified maximum input offset voltage is 50 µV, maximum offset drift is 0.25 µV/°C, and maximum input bias current is 2 nA. Common-mode rejection reaches 115 dB minimum, while the device accepts input over-voltage protection up to ±40 V. These characteristics make the amplifier suitable for bridge outputs, current-shunt measurements, and low-level sensor interfaces.
The wide supply range extends to ±18 V, with operating use supported from ±2.25 V according to the distributor data. Its 1 MHz bandwidth supports faster measurements than a purely high-resolution, slow instrumentation amplifier, while 11 nV/√Hz input noise preserves low-level signal integrity. A 16-pin SOIC package provides a conventional surface-mount footprint suitable for industrial, instrumentation, and test-equipment designs.
Typical applications include precision bridge amplifiers, strain-gauge monitoring, laboratory sensor interfaces, current-shunt amplifiers, and industrial measurement systems. The switched gain function allows one amplifier to serve multiple sensitivity ranges, although the gain-setting network and feedback resistor accuracy must be checked carefully because they directly influence overall measurement accuracy.
Designers should verify input common-mode limits, output swing, gain stability, and supply headroom under the intended load. Input protection improves tolerance to accidental over-voltage, but it does not remove the need for correct polarity, common-mode range, and output-swing analysis. Decoupling should follow the manufacturer datasheet guidance, and sensitive analog traces should be kept away from noisy switching paths.
This page combines verified manufacturer highlights, distributor availability information, same-package alternative candidates, application guidance, and design cautions that help engineers move from part selection to a board-level implementation without overlooking the distinctions between instrumentation amplifiers.
直接替換替代品，適用於 INA115AU — 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： INA115AU （相同外形與佔位） — 差異在於 Package.
INA115AU-1/1K
✅ 直接替換📋 參考替代品（不在目錄中）
INA115AUG4
✅ 直接替換📋 參考替代品（不在目錄中）
INA114AUE4
✅ 直接替換📋 參考替代品（不在目錄中）
INA114BU
✅ 直接替換📋 參考替代品（不在目錄中）
INA118U/2K5
✅ 直接替換聯絡詢價
查看資料表 →INA115AU 最大額定值與電氣特性
| Device Type | Precision instrumentation amplifier |
| Amplifier Count | 1 amplifier |
| Gain-Bandwidth Product | 1 MHz |
| Maximum Offset Voltage | 50 µV |
| Input Noise Density | 11 nV/√Hz |
| Maximum Quiescent Current | 3 mA |
| Maximum Offset Drift | 0.25 µV/°C |
| Maximum Input Bias Current | 2 nA |
| Minimum Common-Mode Rejection | 115 dB |
| Input Over-Voltage Protection | ±40 V |
| Maximum Supply Voltage | ±18 V |
| Minimum Supply Voltage | ±2.25 V |
| Gain Control | Switched gain |
| Slew Rate | 0.06 V/µs |
| 封裝 | 16-pin SOIC (DW) |
| 安裝類型 | Surface mount |
| 工作溫度 | -40 °C to +85 °C |
INA115AU 16-pin soic (dw) 腳位配置指南
INA115AU（16-pin soic (dw) 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： INA115AU.
請參閱 資料表 以查看完整腳位配置。
典型應用
INA115AU 適用於 6 應用s: Strain-Gauge Bridge Measurement, Precision Current-Shunt Monitoring, Industrial Pressure and Sensor Interface, Portable Diagnostic Instrumentation, Data-Acquisition Signal Conditioning, Audio and Instrumentation Signal Chain.
Strain-Gauge Bridge Measurement
The INA115AU fits strain-gauge bridge measurements where millivolt-level differential outputs must be separated from substantial common-mode voltage. Its 50 µV maximum offset and 0.25 µV/°C maximum drift limit static measurement errors, while 115 dB minimum common-mode rejection improves rejection of supply and environmental disturbances. The amplifier is placed between the bridge and the subsequent ADC or measurement controller, with switched gain allowing one input chain to cover several sensitivity ranges. Bridge excitation noise, resistor matching, and input bias current of no more than 2 nA still set the achievable accuracy.
推薦
Precision Current-Shunt Monitoring
The INA115AU is suitable for measuring the small voltage generated across a current shunt in power-conversion and battery systems. The 11 nV/√Hz input noise supports low-level differential extraction, while high input impedance and 2 nA maximum input bias current reduce disturbance of the shunt network. Its 1 MHz bandwidth is useful when the monitored current changes faster than a slow precision-only amplifier can follow. The input over-voltage protection of ±40 V adds robustness against transient faults, although common-mode and output-swing limits must still be respected under all operating conditions.
推薦
Industrial Pressure and Sensor Interface
The INA115AU can condition low-level outputs from pressure, force, displacement, and resistance-based industrial sensors. Its low offset, low drift, and high common-mode rejection help preserve small sensor signals when the sensor is powered from a larger industrial voltage domain. Switched gain lets the same analog front end accommodate different sensor sensitivities and calibration ranges. Because the INA115AU accepts supplies up to ±18 V and protects inputs up to ±40 V, it can simplify protection planning, but designers must verify the actual input common-mode range and ensure the amplifier output remains inside its linear swing at the intended gain.
推薦
Portable Diagnostic Instrumentation
For portable diagnostic and test equipment, the INA115AU provides a combination of low noise, 1 MHz bandwidth, and a 3 mA maximum quiescent current. These characteristics support sensitive measurement channels without requiring the power budget of a much larger high-speed amplifier. The 16-pin SOIC package also supports conventional surface-mount assembly and compact analog boards. A practical design can switch the gain to match different probe sensitivities, but battery-operated equipment should also evaluate supply current across the full operating mode and provide stable, low-noise reference and excitation sources.
推薦
Data-Acquisition Signal Conditioning
The INA115AU is appropriate for multi-channel data-acquisition systems that need a compact precision front end ahead of an ADC. A 1 MHz gain-bandwidth product allows the amplifier to process signals faster than a typical slow instrumentation amplifier, while 50 µV maximum offset and 11 nV/√Hz noise help preserve measurement integrity. Switched gain can adapt the analog channel to different input ranges without changing the PCB footprint. For multiplexed systems, settling time, source impedance, ADC acquisition timing, and gain-dependent bandwidth should be evaluated together rather than treating the 1 MHz figure as a complete settling specification.
推薦
Audio and Instrumentation Signal Chain
The INA115AU can amplify low-level balanced signals in laboratory audio, instrumentation, and communication test equipment. Its low input noise and high common-mode rejection reduce the chance that large shared voltages will contaminate the desired differential signal, and its switched gain supports selectable measurement sensitivity. The 1 MHz bandwidth is sufficient for many general instrumentation signals while avoiding the power and noise cost of a much faster wideband amplifier. In audio-adjacent systems, designers should still examine gain-bandwidth interaction, output-noise contributions, grounding, and whether the 16-pin SOIC footprint provides adequate isolation for sensitive high-impedance sources.
推薦
推薦產品摘要
工程參考資料，適用於 INA115AU — 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 | INA115AU-1/1K | INA115AUG4 | INA114AUE4 | INA114BU | INA118U/2K5 |
|---|---|---|---|---|---|---|
| Package | 16-pin SOIC (DW) | 16-pin SOIC (DW) | 16-pin SOIC (DW) | 16-pin SOIC (DW) | 16-pin SOIC (DW) | 16-pin SOIC (DW) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Device Type | Precision instrumentation amplifier | Precision instrumentation amplifier | Precision instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier |
| Amplifier Count | 1 amplifier | 1 amplifier | 1 amplifier | 1 amplifier | 1 amplifier | 1 amplifier |
| Gain Control | Switched gain | Switched gain | Switched gain | Fixed-gain implementation | Fixed-gain implementation | Fixed gain of 2.5 |
主要差異化特點
- Switched gain in a precision 1 MHz instrumentation amplifier (對比INA118U/2K5)
- Low-noise precision with 50 µV maximum offset (對比INA114AUE4)
- Input over-voltage protection up to ±40 V (對比INA115AU-1/1K)
設計說明
Do not treat the ±40 V input over-voltage rating as the normal input common-mode range. The verified data identifies ±40 V as input protection capability and ±18 V as the maximum supply magnitude. Before layout release, check the selected INA115 gain and supply combination against the manufacturer input common-mode and output-voltage limits. This prevents a design from electrically surviving an over-voltage event while remaining outside the amplifier's linear measurement region.
Preserve a symmetric, low-impedance signal path around the differential inputs. Place input protection, filtering, and gain-setting components close to the INA115AU pins, and keep the two input routes geometrically similar to minimize conversion of common-mode noise into differential error. The 11 nV/√Hz input-noise figure cannot correct for noise introduced by long traces, contaminated connectors, ground potential differences, or an inadequately decoupled reference network.
Follow the manufacturer datasheet for supply decoupling and feedback-network placement. The INA115AU uses switched gain, so its gain-control pins and associated switching circuitry must be kept away from sensitive input and feedback nodes. Use a continuous ground reference beneath the analog section where practical, provide adequate copper for the 16-pin SOIC, and maintain separation from switching regulators, digital return currents, and relay drivers that could couple transient energy into the measurement chain.
Validate output swing at the highest intended gain and lowest expected load because the 1 MHz gain-bandwidth product does not guarantee unrestricted output range. The verified maximum quiescent current is 3 mA, but total system power also depends on the switched-gain network and external load. For ±15 V or ±18 V dual supplies, check headroom at the selected output voltage and consider grounding and supply layout as part of the noise-performance budget.
合規資訊
The verified manufacturer and distributor results do not explicitly state INA115AU RoHS, REACH, lead-free, halogen-free, or conflict-minerals status. AEC-Q100 is treated as not applicable because the verified data describes a general-purpose precision instrumentation amplifier and does not identify an automotive-qualified variant.
