INA118U - Precision Low-Power Instrumentation Amplifier | Texas Instruments
MPN： INA118U ✓ 啟用中INA118U 概覽
An instrumentation amplifier is a specialized amplifier category used to amplify a small differential voltage while rejecting a larger common-mode voltage. INA118 belongs to the precision operational-amplifier hierarchy, combining low-noise input stages, laser trimming, and stable gain-setting resistors in one integrated circuit. This makes it suitable for sensor interfaces, current measurement, portable instrumentation, and industrial acquisition systems where the source signal may be small relative to the surrounding voltage environment.
The INA118U is laser-trimmed for low offset voltage of 50 μV and offset drift of 0.5 μV/°C. According to the manufacturer datasheet, common-mode rejection reaches 110 dB at a gain of 1000. The device consumes only 350 μA of quiescent current, allowing operation from low-voltage supplies and supporting battery-powered measurement systems. Its 800 kHz bandwidth provides useful response for many industrial and sensor signals without requiring a high-speed instrumentation amplifier.
The INA118 uses an external gain-setting resistor, so the gain can be selected for the measurement system while the internal feedback network maintains consistent behavior. The 8-pin SOIC package simplifies assembly on conventional surface-mount PCB designs. Compared with discrete op-amp networks, the integrated instrumentation amplifier reduces component count and simplifies common-mode rejection and gain stability, while still requiring attention to input filtering, reference grounding, output range, and supply bypass capacitors.
Typical applications include low-side current sensing, bridge and pressure-sensor excitation, battery monitoring, biomedical instrumentation, portable test equipment, and industrial process measurement. In these systems, the INA118U converts a small differential sensor voltage into a single-ended output while suppressing common-mode interference. The low quiescent current is especially beneficial when the measurement electronics operate continuously from limited power budgets.
Designers should verify the input common-mode range and output swing against the actual supply voltages, because the usable measurement range is not limited only by the amplifier’s gain and bandwidth. Input filtering should be placed close to the pins, with care taken to preserve differential-mode behavior. A low-noise reference and properly placed supply bypass capacitors are also important when measuring small signals. This page combines verified manufacturer specifications, distributor availability information, practical application guidance, and drop-in replacement analysis to support component selection and board-level implementation.
直接替換替代品，適用於 INA118U — 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： INA118U （相同外形與佔位） — 差異在於 Operating Temperature Range, Package, Number of Circuits, Bandwidth, Gain Range.
INA118U/2K5
✅ 直接替換聯絡詢價
查看資料表 →INA118UB
✅ 直接替換聯絡詢價
查看資料表 →INA118U/2K5G4
✅ 直接替換📋 參考替代品（不在目錄中）
INA114BU/1K
✅ 直接替換📋 參考替代品（不在目錄中）
INA118U 最大額定值與電氣特性
| Device Type | Precision, low-power instrumentation amplifier |
| Number of Circuits | 1 circuit |
| Nominal Gain | 100 |
| Bandwidth | 800 kHz |
| Minimum Supply Voltage | ±2.25 V |
| 靜態電流 | 350 μA |
| Input Offset Voltage | 50 μV |
| Input Offset Voltage Drift | 0.5 μV/°C |
| Common-Mode Rejection | 110 dB at G = 1000 |
| 封裝 | 8-pin SOIC (0.154 inch, 3.90 mm width) |
| 安裝類型 | Surface mount |
| 工作溫度範圍 | -40 °C to +85 °C |
| Package Options in INA118 Family | 8-pin plastic DIP and SO-8 surface-mount packages |
INA118U 8-pin plastic dip and so-8 surface-mount packages 腳位配置指南
INA118U（8-pin plastic dip and so-8 surface-mount packages 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： INA118U.
請參閱 資料表 以查看完整腳位配置。
典型應用
INA118U 適用於 6 應用s: Portable Battery-Powered Sensor Interface, Industrial Current Sensing, Bridge and Pressure Sensor Conditioning, Medical and Diagnostic Instrumentation, Battery Monitoring and Protection, Portable Test and Measurement Equipment.
Portable Battery-Powered Sensor Interface
The INA118U fits portable sensor acquisition because its 350 μA quiescent current and operation from supplies as low as ±2.25 V reduce the burden on a constrained power budget. The 50 μV laser-trimmed offset and 0.5 μV/°C drift help maintain measurement stability when temperature or battery voltage changes. Place the amplifier close to the sensor output, reference the return path correctly, and bypass each supply with the capacitance recommended by the manufacturer datasheet. Compared with a discrete low-noise op-amp network, the integrated instrumentation amplifier reduces board area while preserving differential gain and common-mode rejection.
推薦
Industrial Current Sensing
The INA118U is appropriate for low-side or isolated-side current measurement where a shunt produces a small differential voltage. Its 110 dB common-mode rejection at G = 1000 helps suppress the larger supply and switching voltages surrounding the shunt signal. The 800 kHz bandwidth is suitable for many industrial measurement loops, while the standard gain configuration of 100 amplifies the shunt differential directly. PCB layout should keep the shunt connections short and pair the differential input traces to reduce pickup of unrelated process-control signals.
推薦
Bridge and Pressure Sensor Conditioning
The INA118U can condition differential outputs from resistive bridges, including pressure and strain-related sensing elements. A nominal gain of 100 increases the bridge differential while the high common-mode rejection limits corruption from excitation-side voltage variation. The 50 μV offset specification supports careful low-level bridge measurements, and the 800 kHz bandwidth accommodates many static and moderately dynamic industrial sensors. For best results, keep input traces short, use a stable excitation source, verify the amplifier output range, and place optional input filtering symmetrically so common-mode noise is not unintentionally converted into differential error.
推薦
Medical and Diagnostic Instrumentation
The INA118U is suitable for low-level biomedical signal conditioning when the system requires a low-offset, low-power differential amplifier. The 50 μV input offset and 110 dB common-mode rejection at G = 1000 can help preserve small physiological or diagnostic signals in the presence of larger body-electrode or equipment common-mode voltages. Its 350 μA quiescent current supports portable monitoring equipment. Medical designs must still validate patient-safety isolation, leakage, applied-voltage limits, electrode protection, and applicable regulatory requirements independently; those product-level safety claims are not established by the supplied INA118 data.
推薦
Battery Monitoring and Protection
The INA118U can amplify the differential voltage produced by a battery or power-system sensing network for monitoring and protection electronics. Its low 350 μA quiescent current is valuable in continuously operating systems, while the precision offset specification helps preserve accuracy as the measured voltage changes. The ±2.25 V minimum supply capability supports compact dual-rail implementations. Designers must confirm that battery transients remain inside the device’s absolute maximum ratings and that the input common-mode and output swing are valid over the complete battery range.
推薦
Portable Test and Measurement Equipment
The INA118U is appropriate for handheld meters and portable data-acquisition systems that need to measure low-level differential signals without a large power budget. Its 800 kHz bandwidth accommodates many general-purpose sensor and test signals, while the integrated instrumentation-amplifier architecture reduces the number of external precision components. The laser-trimmed 50 μV offset supports repeatable readings, and operation down to ±2.25 V supports compact isolated power systems. A practical implementation should provide local supply bypassing, maintain a clean reference return, and account for connector and lead errors when estimating full-system accuracy.
推薦
工程參考資料，適用於 INA118U — 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 | INA118U/2K5 | INA118UB | INA118U/2K5G4 | INA114BU/1K | INA128U |
|---|---|---|---|---|---|---|
| Package | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Device Type | Precision, low-power instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier |
主要差異化特點
- Documented low-power operation (對比INA118U/2K5)
- Explicit precision specifications (對比INA114BU/1K)
- Verified manufacturer application support (對比INA128U)
設計說明
Keep the two input traces short, appropriately spaced, and routed as a differential pair to minimize pickup of unrelated noise. Connect input filtering close to the amplifier pins, and preserve the intended common-mode and differential cutoffs. The INA118U provides 110 dB common-mode rejection at G = 1000, but PCB leakage and mismatched impedances can still create differential errors that the datasheet specifications do not represent.
Bypass each power-supply pin directly to the appropriate ground plane with the capacitance and layout specified by the Texas Instruments INA118 datasheet. The device operates from supplies as low as ±2.25 V, but low minimum supply voltage does not remove transient, startup, or output-swing constraints. Verify the input common-mode range and output voltage under the lightest expected load before finalizing the dual-rail supply.
Do not assume that an INA118 family member with a similar order code is electrically identical. INA118U/2K5 and INA118U/2K5G4 use gain-related suffixes, while the supplied TI support result indicates that INA118U and INA118UB have differences in box size and electrical-characteristic entries. Confirm the exact gain equation, external resistor, electrical limits, and pin configuration before substituting any alternative.
合規資訊
The supplied verified excerpts identify the manufacturer, package, operating-temperature range, and precision performance, but they do not explicitly state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status.
