INA128HD - 130dB CMRR Low-Power Instrumentation Amplifier | TI
Артикул: INA128HD ✓ АктивенINA128HD Обзор
An instrumentation amplifier is a specialized amplifier that amplifies the voltage difference between two inputs while rejecting signals common to both inputs. This three-operational-amplifier architecture belongs to the broader measurement-amplifier and analog-signal-conditioning hierarchy. It is especially useful when a small sensor voltage is mixed with a larger common-mode voltage and the measurement requires high input impedance, accurate differential gain, and low output offset.
Key characteristics include 25 µV typical offset voltage, 93 dB minimum CMRR at gain settings of 100 or higher, a 4 V/µs slew rate, and a gain equation based on a 49.4 kΩ gain-setting resistor. Input bias current is listed as 50 nA typical. These features allow the INA128HD to preserve small differential signals while rejecting power-supply ripple, ground offsets, and other common-mode disturbances.
The INA128 uses a current-feedback input stage to maintain usable bandwidth at higher closed-loop gains. A single resistor between the gain-setting terminals establishes the desired gain, while the internal amplifier stages provide differential sensing and single-ended output. The manufacturer describes the INA128-HT as a laser-trimmed design with low offset and high CMRR, making it appropriate for precision analog front ends where gain accuracy and signal purity are more important than minimum cost.
Typical uses include Wheatstone bridge sensing, pressure and force measurement, biomedical instrumentation, industrial sensor acquisition, and low-level differential receiver circuits. The 8-pin SOIC package is also practical for high-density analog boards, although the specified operating temperature range and total input error should be checked against the mechanical and environmental requirements of the target equipment.
For PCB design, place the gain resistor close to pins 1 and 8 to minimize parasitic resistance and instability. Keep input and reference-node routing away from switching nodes and high-current return paths. Check the maximum differential input voltage, common-mode range, supply limits, and output swing in the manufacturer datasheet before finalizing the sensor interface.
This product page combines manufacturer specifications, sourcing guidance, application analysis, and same-package drop-in comparisons. It also highlights practical PCB and signal-integrity considerations that help engineers evaluate the INA128HD beyond a basic parametric component listing.
Аналоги без доработки для INA128HD — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
Варианты в этой серии
Модели той же серии, совместимые без доработки с INA128HD (тот же форм-фактор и посадочное место) — отличается по Package, Architecture, Product Type, Quiescent Current, RoHS Status.
INA128UA
✅ Прямая заменаУточнить цену
Открыть даташит →INA141U
✅ Прямая заменаУточнить цену
Открыть даташит →INA129HD
✅ Прямая замена ⚠️ Характеристики не проверены📋 Справочный аналог (нет в каталоге)
AD620BR
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
AD621BR
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
INA128HD Максимальные параметры и электрические характеристики
| Amplifier Type | Precision instrumentation amplifier |
| Number of Channels | 1 channel |
| Common-Mode Rejection Ratio | 130 dB |
| Common-Mode Rejection Ratio at Gain 100 or Higher | 93 dB minimum |
| Typical Offset Voltage | 25 µV |
| Typical Input Bias Current | 50 nA |
| Gain Range | 1 to 10,000 V/V |
| Gain-Bandwidth Product | 1.3 MHz |
| Slew Rate | 4 V/µs |
| Typical Quiescent Current | 700 µA |
| Supply Voltage Range | 4.5 V to 36 V total, equivalent to ±18 V |
| Maximum Input Protection Range | ±40 V |
| Gain-Setting Resistor | 49.4 kΩ |
| Корпус | 8-pin SOIC, 0.154 inch body width, 3.90 mm |
| Тип монтажа | Surface mount |
| Packaging | Bulk |
Конфигурация выводов INA128HD
| Контакт 1 | RG — Gain-setting resistor connection |
| Контакт 2 | IN- — Inverting input |
| Контакт 3 | IN+ — Noninverting input |
| Контакт 4 | V- — Negative power supply |
| Контакт 5 | REF — Reference input |
| Контакт 6 | OUT — Analog output |
| Контакт 7 | V+ — Positive power supply |
| Контакт 8 | RG — Gain-setting resistor connection |
Типичное применение
INA128HD подходит для 6 применениеs: Wheatstone Bridge Sensor Conditioning, Medical Instrumentation Signal Acquisition, Industrial Pressure and Force Measurement, Low-Level Differential Receiver, Battery-Powered Sensor Node, Precision Analog Data Acquisition.
Wheatstone Bridge Sensor Conditioning
The INA128HD fits bridge-based measurements because its 130 dB CMRR suppresses the bridge excitation voltage appearing equally at both inputs, while 25 µV typical offset and 50 nA typical input bias current preserve the integrity of small imbalance signals. Place it between the bridge and the system ADC, using one 49.4 kΩ-family resistor to establish gain from 1 to 10,000. The 1.3 MHz gain-bandwidth product and 4 V/µs slew rate support responsive sensor conditioning, but the output must remain inside the device's specified swing range.
Рекомендуется
Medical Instrumentation Signal Acquisition
The INA128HD is appropriate for low-level biomedical signal acquisition because its precision input stage combines 130 dB CMRR, 25 µV typical offset voltage, and 50 nA typical input bias current. These characteristics help reject mains-related common-mode interference and preserve small differential signals from physiological sensors. Its 700 µA typical quiescent current also benefits compact systems, although medical qualification requirements, isolation barriers, noise density, and the complete operating temperature range must be evaluated separately before deployment.
Рекомендуется
Industrial Pressure and Force Measurement
For pressure, load, and force transducers, the INA128HD can amplify a small full-scale differential output riding on a larger common-mode excitation voltage. The 130 dB CMRR improves rejection of ground offsets and electrical noise, while the 1.3 MHz bandwidth preserves signal shape when moderate closed-loop gains are used. Input protection to ±40 V provides additional margin for external wiring, but the application still needs surge and ESD protection appropriate to the industrial environment and a gain resistor with suitable tolerance and temperature stability.
Рекомендуется
Low-Level Differential Receiver
The INA128HD can serve as a front end for sensors whose useful output is the difference between two larger potentials, such as resistive bridges or ratiometric probes. The three-amplifier topology provides accurate differential gain, while 130 dB CMRR limits the impact of shared disturbances. A single gain resistor makes calibration and replacement straightforward. Designers should still account for input bias-current error, common-mode limits, resistor tolerance, reference-ground noise, and output-voltage headroom when setting the analog gain.
Рекомендуется
Battery-Powered Sensor Node
The INA128HD's 700 µA typical quiescent current is advantageous in battery-powered sensor nodes where the instrumentation amplifier must remain active while monitoring a slow-changing differential signal. The 8-pin SOIC package supports compact analog boards, and the device offers gains up to 10,000 for low-amplitude outputs. The main trade-off is supply headroom: battery systems must maintain enough voltage for the input common-mode range and output swing, while power-gating strategies should avoid disturbing sensitive measurement nodes.
Рекомендуется
Precision Analog Data Acquisition
The INA128HD can front-end a high-resolution data-acquisition channel when a small differential sensor output must be amplified before conversion. Its 25 µV typical offset voltage, 130 dB CMRR, and 4 V/µs slew rate provide a useful combination of accuracy and dynamic behavior. Gain selection must balance bandwidth against the target signal bandwidth, and the reference node should be connected to a low-impedance ground unless deliberate output-offset correction is required. PCB symmetry and guarding are important for achieving the intended CMRR.
Рекомендуется
Сводка рекомендуемых товаров
Справочные инженерные данные для INA128HD — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар | INA128UA | INA141U | INA129HD | AD620BR | AD621BR |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices | Analog Devices |
| Package | 8-SOIC (0.154 inch, 3.90 mm width) | 8-SOIC (0.154 inch, 3.90 mm width) - same | 8-SOIC (0.154 inch, 3.90 mm width) - same | 8-SOIC (0.154 inch, 3.90 mm width) - same | 8-SOIC (0.154 inch, 3.90 mm width) - same | 8-SOIC (0.154 inch, 3.90 mm width) - same |
| Gain-Setting Method | Single 49.4 kΩ-family resistor using the INA128 equation | Single resistor using the INA128 equation | Single resistor; equation must be verified | Single resistor using the INA129 equation | Single resistor; equation must be verified | Discrete gain-selection topology |
Ключевые отличия
- Higher stated CMRR in a precision low-power instrumentation amplifier (против INA128UA)
- Single-resistor gain programming across a 1-to-10,000 range (против AD621BR)
- High-temperature INA128-HT family positioning (против INA141U)
- Low 700 µA typical quiescent current (против AD620BR)
Заметки по проектированию
Connect the gain resistor directly between pins 1 and 8 and keep it short, because parasitic resistance in these connections can alter gain and contribute to instability. Route the two differential inputs symmetrically, avoid copper beneath high-impedance input nodes, and provide a quiet ground return. The INA128's high CMRR can only be realized when the sensor source, grounding, and PCB geometry do not introduce unequal impedance or leakage between the input paths.
Do not assume that an 8-pin SOIC alternative is automatically interchangeable. INA129HD uses a different gain equation, and AD621BR uses a different gain-selection method. Recalculate the gain-setting component and verify input bias current, offset voltage, common-mode range, output swing, bandwidth, and operating temperature before replacing the INA128HD. This check is essential even when the PCB land pattern remains unchanged.
The REF pin sets the output reference and can inject noise if left floating or connected to a noisy return. For a ground-referenced unipolar output, connect it to a low-impedance analog ground with a short trace. If output-offset calibration is required, drive REF from a low-noise source and account for its noise and drift. Keep the reference route separated from switching nodes and high-current power-return paths.
Check the complete signal path against both positive and negative supply rails, including input common-mode limits and output swing. Although the INA128HD supports supplies up to ±18 V and protected inputs to ±40 V, those limits do not guarantee linear operation for every combination of input and output voltage. Decouple each supply pin locally, verify startup behavior when the sensor excitation changes, and avoid relying on absolute-maximum ratings as normal operating limits.
Информация о соответствии
The INA128HD ordering details identify a high-temperature family member, but no specific RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status is stated in the cited product records.
