INA115AU-1 - 1 MHz Precision Instrumentation Amplifier | TI
MPN： INA115AU-1 ✓ 啟用中INA115AU-1 概覽
An instrumentation amplifier is a specialized analog amplifier that measures the voltage difference between two inputs while rejecting common-mode signals. Its internal three-op-amp architecture provides high input impedance, accurate differential gain, and a defined gain relationship, making it more convenient than a discrete difference amplifier for sensor front ends. Within the broader hierarchy, an instrumentation amplifier is an analog amplifier, a signal-conditioning IC, and part of a measurement and control system.
The INA115 family combines precision input offset performance with low input-referred noise and a bandwidth of 1 MHz. Its switched-gain architecture permits gain to be selected through an external resistor connected to the gain-setting pin. The 50 uV offset specification and 11 nV/√Hz noise density are important when resolving millivolt-level or microvolt-level signals, while the 3 mA supply current supports low-power measurement systems.
INA115AU-1 operates from dual supplies of ±2.25 V to ±18 V, as identified by Texas Instruments for the INA115AU/1K ordering configuration. The 0.06 V/us slew rate supports accurate settling of larger signal steps. Because the amplifier is designed for differential measurements, input-common-mode range, output swing, and input bias behavior must be checked against the actual signal and supply voltages before the circuit is released for production.
Typical uses include bridge-transducer and strain-gauge front ends, precision current measurement, biomedical instrumentation, laboratory measurement equipment, and industrial sensor interfaces. The switched-gain capability simplifies systems in which several gain ranges are required, while the combination of 1 MHz bandwidth, 50 uV offset, and 11 nV/√Hz noise supports accurate signal capture without an unnecessarily high-power amplifier.
The principal design consideration is the gain-setting resistor and its associated noise. Use a resistor with suitable low-noise characteristics and keep the gain network close to the gain pin to minimize parasitic capacitance. Input filtering, common-mode rejection, and output settling should be evaluated together because a high-bandwidth amplifier can amplify high-frequency interference as well as the wanted differential signal.
This product page combines the exact manufacturer highlights with application guidance, package information, and a practical comparison of documented alternatives. It also highlights the distinction between electrical equivalence and packaging-only ordering codes, helping engineers make a board-level replacement decision without confusing tape-and-reel formats with functional alternatives.
直接替換替代品，適用於 INA115AU-1 — 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。
INA115AUG4
✅ 直接替換📋 參考替代品（不在目錄中）
INA115AUG4-ND
✅ 直接替換📋 參考替代品（不在目錄中）
INA115AU-1 最大額定值與電氣特性
| Amplifier Type | Precision instrumentation amplifier |
| Number of Circuits | 1 circuit |
| Gain-Bandwidth Product | 1 MHz |
| Input Offset Voltage | 50 uV |
| Input-Referred Noise Density | 11 nV/√Hz |
| 供應電流 | 3 mA |
| Minimum Supply Voltage | ±2.25 V |
| Maximum Supply Voltage | ±18 V |
| Slew Rate | 0.06 V/us |
| Gain Control | External switched-gain resistor |
| 腳位數 | 16 pins |
| 封裝 | 16-pin SOIC (DW) |
| 安裝類型 | Surface mount |
| Minimum Operating Temperature | -40 °C |
| RoHS 狀態 | unknown |
| REACH Status | unknown |
| AEC-Q100 Qualification | not_applicable |
INA115AU-1 16-pin soic (dw) 腳位配置指南
INA115AU-1（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-1.
請參閱 資料表 以查看完整腳位配置。
典型應用
INA115AU-1 適用於 6 應用s: Bridge and Strain-Gauge Signal Conditioning, Precision Current Measurement, Biomedical Instrumentation, Laboratory Measurement Equipment, Industrial Sensor Interfaces, Audio and Communication Signal Conditioning.
Bridge and Strain-Gauge Signal Conditioning
The INA115AU-1 fits bridge and strain-gauge front ends where the desired measurement is a small differential voltage superimposed on a larger common-mode level. Its 50 uV input offset voltage and 11 nV/√Hz input-noise density help preserve weak sensor outputs, while the 1 MHz gain-bandwidth product can capture dynamic events without requiring a much higher-power amplifier. The external switched-gain network should be implemented with a low-noise resistor placed close to the gain terminal, and the bridge excitation should be referenced cleanly to the amplifier input and supply arrangement.
推薦
Precision Current Measurement
For precision current measurement, the INA115AU-1 can amplify the differential voltage produced across a small shunt without requiring the input signal to be referenced to ground. The 11 nV/√Hz input-noise density is valuable when the shunt voltage is in the millivolt range, and the 50 uV offset specification helps control error at low signal levels. The 0.06 V/us slew rate supports measurement of changing current transients. Designers should account for shunt resistance, amplifier input bias, resistor noise, and the common-mode voltage present across the sensing element.
推薦
Biomedical Instrumentation
The INA115AU-1 is appropriate for low-amplitude biomedical instrumentation front ends, including physiological-signal acquisition and isolated-sensor interface stages after isolation. The combination of 50 uV input offset voltage, 11 nV/√Hz noise density, and a 1 MHz gain-bandwidth product provides a useful balance between precision and bandwidth. Its 3 mA supply current also supports portable power budgets. Input protection, patient-safety isolation, right-leg or reference grounding, and electrode-specific filtering must be implemented outside the instrumentation amplifier.
推薦
Laboratory Measurement Equipment
The INA115AU-1 can serve as the precision differential input stage in laboratory meters, programmable instrumentation, and automated test systems. The 1 MHz gain-bandwidth product supports higher-bandwidth measurements than a slow precision-only amplifier, while the 50 uV offset voltage and 11 nV/√Hz noise density help establish a low measurement floor. External switched gain permits multiple sensitivity ranges without changing the amplifier package. Calibration should include offset, gain, bandwidth, and common-mode rejection across the actual source impedance and test bandwidth.
推薦
Industrial Sensor Interfaces
The INA115AU-1 is well suited to industrial sensor interfaces that produce small differential outputs, including pressure, temperature, position, and process-control transducers. The low 11 nV/√Hz input-noise density supports signal conditioning at the input, and the switched-gain function allows several measurement ranges within one analog design. The 3 mA supply current is favorable for distributed industrial electronics, although long cable runs require filtering and protection against surge, ground-loop, and common-mode conditions before the signal reaches the amplifier.
推薦
Audio and Communication Signal Conditioning
The INA115AU-1 can amplify balanced low-level communication or audio signals when the source is differential and requires high input impedance. Its 1 MHz gain-bandwidth product provides substantially more bandwidth than a precision DC-only amplifier, while the 50 uV offset and 11 nV/√Hz noise density are valuable near the signal floor. In practical circuits, the external gain resistor must include an appropriate bandwidth compensation arrangement as directed by the manufacturer, and the layout should minimize ground imbalance and coupling from switching circuitry.
推薦
推薦產品摘要
工程參考資料，適用於 INA115AU-1 — 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 | INA115AUG4 | INA115AUG4-ND |
|---|---|---|---|
| Package | SOIC-16 (DW) | SOIC-16 (DW) | SOIC-16 (DW) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Product Type | Precision instrumentation amplifier | Precision instrumentation amplifier | Precision instrumentation amplifier |
| Gain-Bandwidth Product | 1 MHz | 1 MHz | 1 MHz |
| Input Offset Voltage | 50 uV | 50 uV | 50 uV |
| Input-Referred Noise Density | 11 nV/√Hz | 11 nV/√Hz | 11 nV/√Hz |
| Supply Current | 3 mA | 3 mA | 3 mA |
| Supply Voltage Range | ±2.25 V to ±18 V | ±2.25 V to ±18 V | ±2.25 V to ±18 V |
| Slew Rate | 0.06 V/us | 0.06 V/us | 0.06 V/us |
| Gain Control | External switched-gain resistor | External switched-gain resistor | External switched-gain resistor |
主要差異化特點
- Precision offset performance (對比INA115AUG4)
- Low input-noise operation (對比INA115AUG4-ND)
- Bandwidth and gain flexibility (對比INA115AUG4)
設計說明
Route differential inputs as a compact, symmetric pair and terminate both inputs close to the device. Keep the external gain-setting resistor adjacent to the gain terminal, and route the resistor return directly to the device ground rather than through a shared high-current path. This reduces parasitic capacitance, ground gradients, and common-mode conversion that can degrade the 50 uV offset and 11 nV/√Hz noise performance.
Do not assume that a low-noise input amplifier compensates for a noisy gain resistor. Choose a resistor type and value suitable for the selected gain, follow the manufacturer's compensation guidance for the closed-loop bandwidth, and include the resistor and input-referred noise in the total noise calculation. Also verify the input common-mode range and output swing at the lowest specified supply voltage.
Keep switching regulators, relays, clock lines, and high-current return paths away from the input and gain nodes. If the source can carry electrostatic discharge or industrial transients, place appropriately rated protection ahead of the amplifier and control its capacitance so the 1 MHz bandwidth is not unintentionally degraded. Use a quiet reference and ground architecture to preserve common-mode rejection.
Place input and output bypass capacitors close to their respective pins and provide adequate supply decoupling for the 3 mA device current plus transient load. Check the bypass capacitors for effective bias, voltage derating, and effective capacitance across the full measurement bandwidth. Stable operation depends on the capacitor characteristics and placement recommended in the manufacturer application circuit, not only on their nominal capacitance.
合規資訊
The INA115 is an instrumentation amplifier rather than an automotive-qualified power semiconductor; no specific AEC-Q100 qualification statement is identified for this ordering option.
