INA115BU - 1MHz Low-Noise INA | Texas Instruments
MPN： INA115BU ✓ 啟用中INA115BU 概覽
An instrumentation amplifier is a differential analog signal-conditioning IC that amplifies the voltage between two inputs while rejecting common-mode interference. Its internal hierarchy is instrumentation amplifier, differential amplifier, analog amplifier, and semiconductor. The three-op-amp architecture uses resistive feedback to establish gain, high input impedance, and accurate differential gain control. Exposed input-amplifier connections permit switched-gain networks and alternative feedback arrangements.
Key performance features include an offset voltage of 50 uV maximum, input voltage drift of 0.25 uV/degree C maximum, input bias current of 2 nA maximum, and common-mode rejection of 115 dB minimum. The device also provides input over-voltage protection to plus or minus 40 V, making it suitable for measurement interfaces where transient or fault conditions may exceed the normal common-mode range.
The INA115BU combines 1 MHz bandwidth with 11 nV/sqrt(Hz) noise density. Its slew rate of 0.6 V/us supports accurate reproduction of moderate-frequency waveforms, while the external gain-setting network allows tradeoffs among gain, bandwidth, and noise. The instrumentation-amplifier topology is particularly useful when a low-level sensor differential must be measured in the presence of a larger common-mode voltage.
Typical applications include bridge and strain-gauge signal conditioning, precision current measurement, biomedical instrumentation, industrial process-control sensors, and low-level differential data acquisition. The input-overvoltage protection and high common-mode rejection are useful in industrial environments, while low input bias current supports high-impedance sensor interfaces.
Designers should place input and feedback resistors close to the device, maintain symmetric input routing, and verify stability with the intended gain network. Gain-setting resistance must also be checked against the required bandwidth, because the effective gain bandwidth relationship becomes increasingly important as closed-loop gain rises.
This product summary combines the manufacturer specifications with practical guidance for gain selection, noise analysis, overvoltage protection, and PCB implementation. It also identifies verified nearby instrumentation amplifiers for engineers evaluating replacement or design-comparison requirements.
直接替換替代品，適用於 INA115BU — 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： INA115BU （相同外形與佔位） — 差異在於 Amplifier Type, Package, Architecture, Bandwidth, Gain Range.
INA114BU
✅ 直接替換聯絡詢價
查看資料表 →INA118U/2K5
✅ 直接替換聯絡詢價
查看資料表 →INA115BU 最大額定值與電氣特性
| Amplifier Type | Precision instrumentation amplifier |
| Architecture | Three-op-amp instrumentation amplifier |
| Bandwidth | 1 MHz |
| Maximum Offset Voltage | 50 uV |
| Input Offset Voltage Drift | 0.25 uV/degree C maximum |
| Input Noise Density | 11 nV/sqrt(Hz) |
| Maximum Input Bias Current | 2 nA |
| Minimum Common-Mode Rejection | 115 dB |
| Input Over-Voltage Protection | plus or minus 40 V |
| Supply Voltage Range | 2.25 V to 18 V |
| Maximum Total Supply Voltage | plus or minus 18 V |
| Slew Rate | 0.6 V/us |
| Maximum Quiescent Current | 3 mA |
| Number of Amplifiers | 1 circuit |
| 封裝 | 16-pin SOIC |
| 安裝類型 | Surface mount |
| Switched Gain | Enabled through exposed input-amplifier connections |
INA115BU 16-pin soic 腳位配置指南
INA115BU（16-pin soic 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： INA115BU.
請參閱 資料表 以查看完整腳位配置。
典型應用
INA115BU 適用於 6 應用s: Strain-Gauge Bridge Signal Conditioning, Precision Current Measurement, Industrial Process Sensor Interface, Biomedical Instrumentation, Low-Level Differential Data Acquisition, Switched-Gain Measurement Front End.
Strain-Gauge Bridge Signal Conditioning
The INA115BU is well suited to low-level bridge outputs because it combines 50 uV maximum offset voltage, 2 nA maximum input bias current, and 115 dB minimum common-mode rejection. It can amplify the differential bridge signal while rejecting much of the larger common-mode voltage present at the sensor inputs. The three-op-amp architecture and exposed input-amplifier connections also support accurate high-gain arrangements. Designers should establish the required bridge excitation, reference the output around the appropriate common-mode voltage, and select the gain resistor using the manufacturer gain and bandwidth equations.
推薦
Precision Current Measurement
For shunt-based current measurement, the INA115BU provides the low offset and high common-mode rejection needed to recover a small differential voltage placed on a larger supply rail. Its 11 nV/sqrt(Hz) input noise is useful when the measured current is near the lower end of the shunt circuit's range. The device can operate from a 2.25 V minimum supply and includes plus or minus 40 V input over-voltage protection. Keep the Kelvin sense connections symmetric and isolate the shunt from high-current paths to minimize parasitic thermoelectric errors.
推薦
Industrial Process Sensor Interface
The INA115BU can condition low-level differential outputs from pressure, temperature, and chemical sensors operating in electrically noisy industrial environments. Its 115 dB minimum common-mode rejection suppresses much of the unwanted signal common to both sensor inputs, while the 1 MHz bandwidth preserves moderate-frequency process information. The 16-pin SOIC package allows conventional surface-mount assembly and access to gain-network components. Layout should preserve input symmetry, provide a clean reference return, and place feedback resistors close to the device to reduce pickup and gain errors.
推薦
Biomedical Instrumentation
The INA115BU can amplify small differential bio-sensor signals when its low offset, low input bias current, and high common-mode rejection are important. The 11 nV/sqrt(Hz) input noise supports low-level signal acquisition, while the three-op-amp topology provides high differential input impedance. Biomedical designs still require careful isolation, patient protection, leakage-current control, and verification of applicable safety requirements. The amplifier's protected input stage should not be treated as the complete patient-protection network, and referenced designs should be followed when the circuit connects to human subjects.
推薦
Low-Level Differential Data Acquisition
The INA115BU is appropriate for front-end conditioning ahead of an ADC when a sensor produces a small differential output and requires a clean ground-referenced measurement. Its 1 MHz bandwidth is sufficient for many moderate-speed acquisition channels, while the low quiescent current of 3 mA maximum supports compact systems. The external gain network makes it possible to trade bandwidth for sensitivity. Confirm the ADC input range, drive the output into the required settling time, and verify that the selected gain does not introduce unacceptable settling error into the sampling system.
推薦
Switched-Gain Measurement Front End
The INA115BU's additional connections to the input amplifiers, identified in the manufacturer datasheet, support improved high-gain accuracy and switched-gain circuit arrangements. This makes it useful in multirange instrumentation where the system changes gain while retaining a differential measurement architecture. The selection process should evaluate gain error, bandwidth, settling time, and switch resistance at every range. Feedback and switching components should be placed close to the amplifier, while input traces remain short and symmetric to preserve noise and common-mode performance.
推薦
推薦產品摘要
工程參考資料，適用於 INA115BU — 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 | INA114BU | INA118U |
|---|---|---|---|
| Package | 16-pin SOIC | 16-pin SOIC | 16-pin SOIC |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Bandwidth | 1 MHz | 1 MHz | 70 kHz at gain 100 |
| Supply Voltage Range | 2.25 V to 18 V | 2.25 V to 18 V | 2.25 V to 18 V |
| Input Architecture | Three-op-amp instrumentation amplifier | Three-op-amp instrumentation amplifier | Current-feedback input circuitry |
主要差異化特點
- Lower specified offset than many general-purpose alternatives (對比INA118U)
- Access to input-amplifier nodes supports specialized gain networks (對比INA114BU)
- Higher-bandwidth architecture for precision gain-set measurements (對比INA118U)
設計說明
Route the two inputs as a closely matched differential pair and connect the amplifier-side input return to the same quiet reference used by the source. Keep the external gain-setting resistors close to their associated device pins, and avoid routing input and feedback nets beneath switching nodes. Symmetrical geometry helps reduce conversion of common-mode pickup into differential error, which is especially important because the INA115BU's 50 uV maximum offset is small relative to many precision sensor outputs.
Do not assume that the 1 MHz bandwidth rating applies at every closed-loop gain. The actual response depends on the selected feedback resistance and the manufacturer's gain-bandwidth equations. When changing from INA114BU to INA115BU, also verify whether the circuit uses the exposed A1 and A2 input-amplifier connections. If it does, those nets require equivalent gain accuracy and stability analysis rather than a straightforward functional substitution.
For low-level sensor measurements, use a low-noise reference arrangement and provide stable input and output bypassing close to the device. The 11 nV/sqrt(Hz) input-noise specification makes layout-induced pickup a meaningful error source even when the amplifier itself performs well. Shield or guard exposed sensitive nodes where necessary, maintain a quiet ground-current path, and verify the assembled board with the sensor and analog source disconnected to identify residual noise before interpreting it as sensor activity.
合規資訊
The manufacturer product and datasheet pages do not state explicit compliance results for the INA115BU ordering option in the cited text. RoHS, REACH, AEC-Q100, lead-free, halogen-free, and conflict-minerals status therefore remain unknown.