INA114AU - 1MHz Precision INA Amplifier | Texas Instruments
MPN: INA114AU ✓ ActiveINA114AU Overview
An instrumentation amplifier is a specialized amplifier that measures small differential signals while rejecting large common-mode voltages. The INA114 belongs to the precision instrumentation-amplifier hierarchy, where instrumentation amplifier, differential amplifier, analog signal-conditioning IC, and power-management-adjacent signal-chain component describe its principal function. Its three-op-amp architecture provides high input impedance and accurate differential gain, making it useful when the source resistance can vary or when a conventional op-amp differential circuit would suffer input-bias-current errors.
Key features include 50 µV maximum offset voltage, 0.25 µV/°C maximum offset drift, 2 nA maximum input bias current, and 115 dB minimum common-mode rejection. A single external resistor selects gains from 1 to 10,000, while the 1 MHz gain-bandwidth product supports a 0.06 V/µs slew rate. These characteristics favor precision measurement rather than high-speed video amplification, although the 1 MHz bandwidth is sufficient for many industrial, medical, and instrumentation signals.
The INA114 uses a three-op-amp internal architecture to establish differential gain while maintaining high input impedance. Laser trimming reduces offset errors, and the internal input protection network allows each input to withstand ±40 V without damage. With a typical 3 mA quiescent-current specification and operation down to ±2.25 V, the device supports dual-supply precision systems and single 5 V applications using suitable output-reference arrangements.
Typical uses include bridge and strain-gauge conditioning, current-shunt measurement, laboratory instrumentation, ECG and physiological-signal acquisition, and industrial sensor interfaces. In a bridge circuit, the low offset and high common-mode rejection improve stability in the presence of long cables or supply variation. For sensor excitation, the amplifier converts a small millivolt-level differential output into a voltage suitable for an ADC.
Designers must select the gain resistor carefully because its tolerance, temperature coefficient, and parasitic capacitance affect gain accuracy and bandwidth. Decoupling capacitors should be placed close to the supply pins, and the reference pin should be configured to provide the required output offset. Input filtering must preserve the required settling time because the internal protection resistors can combine with source capacitance to alter bandwidth.
This product record consolidates verified manufacturer specifications, distributor information, drop-in alternatives, package details, and application guidance. It highlights the engineering trade-offs among gain, bandwidth, input protection, common-mode rejection, and supply requirements that are not apparent from the MPN alone.
Drop-in alternatives for INA114AU — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with INA114AU (same form factor and footprint) — differing in Gain-Bandwidth Product, Maximum Input Bias Current, Minimum Common-Mode Rejection, Package.
INA111AU
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →INA128U
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
INA129U
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →INA114AU Maximum Ratings & Electrical Characteristics
| Amplifier Type | Single-amplifier precision instrumentation amplifier |
| Gain-Bandwidth Product | 1 MHz |
| Input Noise | 11 nV/√Hz |
| Maximum Offset Voltage | 50 µV |
| Maximum Offset Voltage Drift | 0.25 µV/°C |
| Maximum Input Bias Current | 2 nA |
| Minimum Common-Mode Rejection | 115 dB |
| Input Overvoltage Protection | ±40 V |
| Maximum Supply Voltage | ±18 V |
| Minimum Supply Voltage | ±2.25 V |
| Maximum Quiescent Current | 3 mA |
| Gain Range | 1 to 10,000 |
| Slew Rate | 0.06 V/µs |
| Operating Temperature Range | -40°C to +85°C |
| Package | 16-pin SOIC, 3.9 mm wide |
| Mounting Type | Surface mount |
| Internal Architecture | Three-op-amp instrumentation amplifier |
INA114AU Pin Configuration
| Pin 1 | RG — External gain-setting resistor connection |
| Pin 2 | -IN — Inverting input |
| Pin 3 | +IN — Noninverting input |
| Pin 4 | -VS — Negative power-supply connection |
| Pin 5 | REF — Reference input for output-voltage offset |
| Pin 6 | OUT — Amplified output |
| Pin 7 | +VS — Positive power-supply connection |
| Pin 8 | NC — No internal connection |
| Pin 9 | NC — No internal connection |
| Pin 10 | NC — No internal connection |
| Pin 11 | NC — No internal connection |
| Pin 12 | NC — No internal connection |
| Pin 13 | NC — No internal connection |
| Pin 14 | NC — No internal connection |
| Pin 15 | NC — No internal connection |
| Pin 16 | NC — No internal connection |
Typical Applications
INA114AU is suitable for 6 applications: Strain-Gauge and Load-Cell Bridge Conditioning, Precision Current-Shunt Measurement, ECG and Physiological Signal Acquisition, Industrial Sensor and Transducer Interface, Laboratory Instrumentation and Signal Analysis, Battery-Powered Portable Measurement System.
Strain-Gauge and Load-Cell Bridge Conditioning
INA114AU fits strain-gauge and load-cell front ends that require accurate amplification of a small differential bridge signal. Its verified 50 µV maximum offset, 0.25 µV/°C maximum drift, 115 dB minimum common-mode rejection, and 2 nA maximum input bias current reduce errors associated with low-level millivolt outputs. The three-op-amp architecture maintains high differential input impedance, while the single gain-setting resistor simplifies calibration from 1 through 10,000. A practical bridge design places the INA114AU close to the bridge inputs, verifies common-mode limits, and uses a stable reference for output-zero adjustment. The 1 MHz bandwidth provides more margin than required for most slow mechanical measurements, but resistor tolerance and temperature coefficient can dominate gain accuracy.
Recommended
Precision Current-Shunt Measurement
INA114AU is appropriate for measuring differential voltage across a current shunt when the shunt sits near a supply rail and experiences substantial common-mode voltage. The verified 115 dB minimum common-mode rejection helps suppress supply-ripple and switching-node components, while the 2 nA maximum input bias current limits errors from long PCB traces and source impedances. Its 11 nV/√Hz input noise supports precise current measurements, and the 50 µV maximum offset defines a meaningful DC error floor. The amplifier is normally connected between the shunt terminals with the output referenced to ground for bipolar measurement or to a controlled midpoint for unidirectional current. Engineers should check that the shunt voltage remains within the common-mode range and that the selected gain does not cause amplifier saturation before the transient peak arrives.
Recommended
ECG and Physiological Signal Acquisition
INA114AU can serve as the analog input stage in ECG and other physiological-signal systems where the source is small, differential, and referenced to a common electrode potential. Its low 2 nA maximum input bias current is important when connected to high-impedance electrodes and protection networks, while 115 dB minimum common-mode rejection helps reject interference common to both inputs. The 50 µV maximum offset and 11 nV/√Hz input noise support low-level signal integrity. Designers should place protection resistors close to the connector and verify their leakage and effective noise contribution. Because the INA114AU is not itself a complete medical front end, electrode protection, patient isolation, right-leg-drive circuitry, filtering, diagnostic validation, and applicable safety requirements remain separate design obligations.
Recommended
Industrial Sensor and Transducer Interface
INA114AU is useful for industrial transducers that generate low-level differential signals but share a large common-mode voltage with the measurement electronics. The verified 1 MHz gain-bandwidth product, 115 dB minimum common-mode rejection, and input protection to ±40 V give designers more tolerance for wiring and source conditions than a basic differential amplifier. A single external gain resistor supports adjustment across a broad range of transducer sensitivities. In a practical installation, locate the amplifier near the sensor connector, use short guarded differential routes, and keep return currents away from the input traces. The input-protection rating does not replace correct surge or ESD design, so long industrial cables may still require dedicated protection, filtering, and grounding arrangements.
Recommended
Laboratory Instrumentation and Signal Analysis
INA114AU suits laboratory front ends that combine wide input-range capability with accurate low-level measurement. Its ±40 V protected inputs, ±2.25 V to ±18 V supply range, and adjustable gain from 1 to 10,000 allow one amplifier platform to cover several source ranges. The low offset and high common-mode rejection help preserve measurement integrity, while the 1 MHz bandwidth supports moderately fast signal analysis without requiring a video amplifier. Engineers commonly use the reference pin to establish the output range and select the gain resistor based on expected signal amplitude. For high-accuracy setups, the resistor tolerance, leakage paths, reference impedance, source impedance, and settling time should be included in the uncertainty budget rather than relying on amplifier specifications alone.
Recommended
Battery-Powered Portable Measurement System
INA114AU can support portable and battery-operated instruments because it operates from ±2.25 V supplies and has a verified 3 mA maximum quiescent current. The low bias current of 2 nA reduces measurement errors from high-impedance sensors, while the 50 µV maximum offset remains suitable for many low-level analog channels. A single 5 V arrangement is possible when the output and reference are biased appropriately, although the usable output swing must be checked against the chosen configuration. Power-conscious designs should account for gain-resistor and filter currents in addition to the 3 mA device specification. The 16-pin SOIC package supports compact layouts, but decoupling-capacitor leakage and PCB contamination can become significant when resolving microvolt-level signals in a portable instrument.
Recommended
Recommended Products Summary
Engineering reference data for INA114AU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | INA111AU | INA128U | INA129U |
|---|---|---|---|---|
| Package | 16-pin SOIC | 16-pin SOIC - same | 16-pin SOIC - same | 16-pin SOIC - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
Key Differentiators
- Broad single-resistor gain range (vs INA111AU)
- High bandwidth for a precision instrumentation amplifier (vs INA128U)
- Protected inputs for industrial wiring conditions (vs INA129U)
Design Notes
Place the INA114AU close to the transducer or shunt and route the two input signals as a compact differential pair. Keep the reference and gain-resistor networks away from switching nodes and high-current return paths. Although the inputs tolerate ±40 V, protection is not a substitute for normal common-mode compliance; verify that the instantaneous input voltage remains within the operating limits.
Do not assume that a functional equivalent is a footprint-compatible replacement. The verified cross-reference sources identify AD620, MAX4194, and LT1167 as equivalent-family devices, but those use 8-pin packages rather than the INA114AU 16-pin SOIC. A PCB migration requires package changes, pin reassignment, and a new review of supply, reference, gain-resistor, and input-protection requirements.
Calculate the gain resistor together with total input capacitance and the amplifier’s 1 MHz gain-bandwidth product before assuming adequate settling time. Use a low-noise, low-temperature-coefficient resistor when offset and gain drift matter. Keep filtering capacitors at the inputs only when their leakage and dielectric absorption do not degrade the target microvolt-level measurement.
Use local supply bypassing and route the positive and negative supply connections to their respective pins with short, low-impedance paths. The verified 3 mA maximum quiescent current does not include the external gain resistor or reference-network current. Account for output swing, load current, and supply configuration so the output does not clip before the expected input range is reached.
Compliance Information
The supplied verified data does not state RoHS, REACH, lead-free, halogen-free, conflict-minerals, or AEC-Q100 status. INA114AU is an industrial-temperature instrumentation amplifier, so automotive qualification is not assumed.
