INA118PB - Precision Instrumentation Amplifier | Texas Instruments
料号： INA118PB ✓ 量产中INA118PB 概述
An instrumentation amplifier is a specialized analog amplifier designed to accurately amplify small differential signals while rejecting large common-mode voltages. Its internal three-op-amp architecture and current-feedback input stage provide high input impedance, stable gain, and useful bandwidth at high closed-loop gains. The INA118 belongs to the broader hierarchy of differential amplifier, instrumentation amplifier, analog amplifier, and semiconductor.
The INA118PB is laser trimmed for low offset voltage and low temperature drift, while its internal input protection supports inputs to ±40 V. A single external gain-setting resistor provides gains from 1 to 10,000. According to the Texas Instruments product page, bandwidth remains 70 kHz at a gain of 100, while the low 350 uA quiescent current makes the device suitable for battery-operated and portable measurement systems.
The three-op-amp internal design simplifies instrumentation-amplifier implementation while maintaining precision over the specified temperature range of -40°C to +85°C. Differential inputs minimize sensitivity to common-mode noise, and the low-offset architecture improves accuracy in bridge, shunt, and sensor-interface circuits. Its low-power operation is particularly valuable when every milliamp of supply current affects battery life or thermal design.
Typical uses include bridge-amplifier interfaces, current-shunt measurements, precision sensor conditioning, biomedical instrumentation, industrial process monitoring, and low-noise battery-powered acquisition systems. The protected inputs can improve resilience to accidental signal-chain overvoltage, although the design must still maintain valid supply and common-mode conditions for accurate operation.
Designers should place the gain resistor close to the RG pins, route differential inputs symmetrically, and provide local supply bypassing. Input filtering must account for the protected input network and noise requirements, while PCB cleanliness is important because high-gain measurements amplify small residual errors. The 8-pin plastic DIP format is suitable for through-hole prototypes, legacy systems, and automated test fixtures.
This page combines verified Texas Instruments specifications, distributor availability, same-package drop-in alternatives, and practical engineering guidance. It adds design-focused context for gain selection, bandwidth, input protection, supply bypassing, and PCB implementation that is not directly visible in a distributor listing.
直接替换替代料： INA118PB ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： INA118PB （相同外形与封装尺寸） ——差异在于 Quiescent Current, Product Type, Architecture, Package, Gain Range.
INA118P
✅ 直接替换联系询价
查看数据手册 →INA126P
✅ 直接替换 ⚠️ 规格未核验联系询价
查看数据手册 →INA128P
✅ 直接替换 ⚠️ 规格未核验联系询价
查看数据手册 →INA120P
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
INA149P
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
INA118PB 最大额定值与电气特性
| Product Type | Precision instrumentation amplifier |
| Number of Amplifiers | 1 circuit |
| Architecture | Three-op-amp design |
| Maximum Offset Voltage | 50 uV |
| Maximum Offset Voltage Drift | 0.5 uV/°C |
| Maximum Input Bias Current | 5 nA |
| Minimum Common-Mode Rejection | 110 dB at G = 1000 |
| Maximum Input Voltage | ±40 V |
| Maximum Supply Voltage | ±18 V |
| Minimum Single-Supply Voltage | 1.35 V |
| Minimum Dual-Supply Voltage | ±2.25 V |
| 静态电流 | 350 uA |
| Gain Range | 1 to 10,000 |
| Bandwidth at Gain of 100 | 70 kHz |
| 工作温度范围 | -40°C to +85°C |
| 封装 | 8-pin plastic DIP |
| 安装类型 | Through-hole |
INA118PB 引脚配置
| 引脚 1 | RG — Gain-setting resistor terminal |
| 引脚 2 | IN− — Inverting input |
| 引脚 3 | IN+ — Non-inverting input |
| 引脚 4 | V− — Negative supply terminal |
| 引脚 5 | REF — Reference input |
| 引脚 6 | OUT — Amplified output |
| 引脚 7 | VS — Positive supply terminal |
| 引脚 8 | RG — Gain-setting resistor terminal |
典型应用
INA118PB 适用于 6 应用s: Precision Bridge Sensor Interface, Battery-Powered Data Acquisition, Current Shunt Measurement, Medical Signal Conditioning, Industrial Process Monitoring, Precision Sensor and Transducer Interface.
Precision Bridge Sensor Interface
The INA118PB fits precision bridge measurements because its 50 uV maximum offset, 5 nA maximum input bias current, and 110 dB minimum common-mode rejection at a gain of 1000 help preserve small differential signals from resistive sensors. Place the bridge output across the IN− and IN+ inputs and use one external resistor to establish the required gain from 1 to 10,000. Differential routing and matched input components are important because high gain also amplifies resistor mismatch, leakage, and thermoelectric errors. The 70 kHz bandwidth specified at a gain of 100 provides useful response for many pressure, load, and position systems, although bandwidth and noise must be balanced against measurement speed.
推荐
Battery-Powered Data Acquisition
The INA118PB is appropriate for battery-powered acquisition systems because its quiescent current is only 350 uA while the device supports supplies down to 1.35 V. A dual-supply implementation can operate from ±2.25 V, while higher rails remain available for industrial systems. The amplifier can condition low-level sensor outputs without the higher standing current associated with many precision analog stages. Low power does not eliminate the need for careful layout: place bypass capacitors near the supply pins, keep the RG connection short, and avoid high-leakage PCB contamination when the source impedance is high.
推荐
Current Shunt Measurement
The INA118PB can measure small voltage drops across current-shunt resistors while rejecting the supply or bus voltage appearing in common with the signal. Its 50 uV maximum offset and 110 dB minimum common-mode rejection at a gain of 1000 are valuable when the shunt voltage is only a few millivolts. The input-protection capability extends to ±40 V, adding robustness in systems where the shunt node may experience transients. However, the common-mode and output voltage must remain within operating limits, and Kelvin connections should be used to avoid including copper-drop resistance.
推荐
Medical Signal Conditioning
The INA118PB can serve as the analog front end for low-level biomedical sensor signals when high common-mode rejection, low offset, and low bias current are priorities. The three-op-amp instrumentation-amplifier architecture simplifies differential acquisition while the 350 uA quiescent current supports portable equipment. Input bias current of no more than 5 nA reduces errors with high-impedance bioelectrodes or resistive sensors, although application-specific leakage, isolation, patient safety, and regulatory requirements remain outside the device datasheet. A complete medical design should also address electrode protection, grounding, leakage current, and applicable safety standards.
推荐
Industrial Process Monitoring
The INA118PB is suitable for industrial process monitoring when transducers produce small differential signals over a larger common-mode voltage. Its 70 kHz bandwidth at a gain of 100 supports many sensor-monitoring bandwidths, while the maximum input protection of ±40 V improves tolerance to wiring faults. The device operates across -40°C to +85°C, making it appropriate for industrial temperature environments within that specified range. Designers should provide filtering for sensor bandwidth, maintain clean differential routing, and verify that ground and supply arrangements do not compromise the input common-mode range.
推荐
Precision Sensor and Transducer Interface
The INA118PB provides a compact analog interface for resistive, piezoelectric, and low-voltage transducer outputs where accurate differential amplification is required. The maximum input bias current of 5 nA limits loading errors in high-impedance circuits, and the 1 to 10,000 gain range allows the same family to cover multiple sensor sensitivities. A single external gain resistor simplifies adjustment, but its tolerance and temperature coefficient directly influence overall gain accuracy. Keep the gain resistor close to the RG pins, use a stable reference configuration, and verify bandwidth at the selected gain because the available 70 kHz value is specified at gain 100.
推荐
工程参考数据： INA118PB ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | INA118P | INA126P | INA128P | INA120P | INA149P |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | PDIP-8 | PDIP-8 | PDIP-8 | PDIP-8 | PDIP-8 | PDIP-8 |
| Product Type | Precision instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier | Instrumentation amplifier |
关键差异点
- Low offset for precision differential measurements （对比 INA118P)
- Low-power operation supports portable acquisition （对比 INA118P)
- Protected inputs improve transient tolerance （对比 INA118P)
- Verified high-gain common-mode rejection （对比 INA118P)
设计说明
Route IN+ and IN− as a short, symmetric differential pair and connect the external gain-setting resistor directly between the two RG terminals. Excess trace resistance, thermal gradients, and leakage can create errors that become significant at high gain. Keep the gain resistor close to the device, use a suitable reference connection, and avoid placing noisy switching or digital return currents beneath the sensitive input traces.
Place the supply bypass capacitors close to the VS and V− pins and provide the capacitance required by the manufacturer datasheet. The INA118PB is specified for operation from 1.35 V to 18 V and at dual supplies as low as ±2.25 V, but rail sequencing and output behavior still require validation. Do not interpret the ±40 V input-protection rating as permission to exceed the permitted supply voltage.
Do not select the gain solely from the sensor's full-scale voltage. Include offset, drift, input bias current, common-mode range, output swing, and bandwidth. The specified 70 kHz bandwidth applies at gain 100, so operation at gain 1 or 10,000 requires checking the manufacturer performance curves. Also verify that input filtering does not create excessive phase shift or interact with the protected input network.
合规信息
The supplied verified results do not explicitly state RoHS, REACH, lead-free, halogen-free, or conflict-minerals status for INA118PB. AEC-Q100 is not applicable because the product is not identified as an automotive-qualified device.
