INA129A - Precision Instrumentation Amplifier | Texas Instruments
MPN: INA129A ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
INA129A Overview
An instrumentation amplifier is a specialized amplifier that amplifies the difference between two input signals while rejecting common-mode voltage and providing high input impedance. The INA129A belongs to the broader precision analog signal-conditioning hierarchy: instrumentation amplifier, differential amplifier, analog amplifier, and semiconductor. It is used where sensors, transducers, strain gauges, bridge circuits, and measurement front ends require accurate differential amplification with minimal disturbance to the source.
The INA129 family is designed for low-power precision applications. A single external resistor sets the gain from 1 to 10,000, according to the manufacturer product information. The device provides a wide supply range of ±18 V, a minimum common-mode rejection of 120 dB, input bias current of 5 nA maximum, and input protection to ±40 V. Its current-feedback input stage is particularly useful in higher-gain designs because it preserves bandwidth better than a conventional voltage-feedback input arrangement.
The INA129A can amplify low-level sensor signals in industrial measurement systems, bridge-based load cells, biomedical instrumentation, audio equipment, and data-acquisition systems. Its common-mode rejection helps suppress equal voltages appearing on both inputs, while high input impedance limits loading of the measured source. The ±40 V input protection provides additional robustness when connected to external wiring or larger transients, subject to the complete datasheet ratings and system design limits.
When using INA129A, place the gain-setting resistor close to the appropriate gain pins and keep input and feedback traces short to reduce parasitic capacitance and noise pickup. Check supply decoupling, input common-mode range, output swing, and resistor tolerance before finalizing a design. Because the INA129A is a precision analog amplifier, grounding, shielding, clean references, and careful PCB layout can matter as much as nominal gain accuracy.
This product page combines the verified INA129A electrical and physical details, manufacturer and distributor references, comparison parameters, and practical design guidance. The listed alternatives are limited to candidates supported by the supplied cross-reference data; package and pin compatibility should still be confirmed against the current manufacturer datasheet before substitution.
Drop-in alternatives for INA129A — 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 INA129A (same form factor and footprint) — differing in Mounting Type, Package, Supply Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
INA129UA
✅ Drop-In📋 Reference alternative (not in catalog)
INA129PA
✅ Drop-In📋 Reference alternative (not in catalog)
INA128PA
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →INA129A Maximum Ratings & Electrical Characteristics
| Product Type | Precision instrumentation amplifier |
| Architecture | Three-op-amp instrumentation amplifier |
| Supply Range | ±18 V |
| Gain Range | 1 to 10,000 |
| Bandwidth at Gain 100 | 200 kHz |
| Maximum Offset Voltage | 50 µV |
| Maximum Input Offset Drift | 0.5 µV/°C |
| Maximum Input Bias Current | 5 nA |
| Minimum Common-Mode Rejection | 120 dB |
| Input Protection | ±40 V |
| Low-Power Design | Low-power general-purpose instrumentation amplifier |
| Package | 8-pin SOIC |
| Mounting Type | Surface mount |
| Input Circuit | Current-feedback input circuitry |
| External Gain Setting | Single external resistor |
| Application Class | Precision analog signal conditioning |
INA129A 8-pin soic Pin Configuration Guide
Pin configuration for INA129A (8-pin soic package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for INA129A.
Refer to the datasheet for full pin configuration.
Typical Applications
INA129A is suitable for 6 applications: Bridge-Based Sensor Front Ends, Industrial Data Acquisition, Biomedical Instrumentation, Audio and Communication Amplification, Power and Motor Monitoring, Test and Measurement Equipment.
Bridge-Based Sensor Front Ends
The INA129A suits Wheatstone-bridge and strain-gauge front ends because it amplifies small differential signals while providing high common-mode rejection and low input bias current. Its verified minimum CMR of 120 dB helps reduce errors when both bridge inputs move around a shared reference voltage. The ±40 V input-protection feature can improve robustness in wired sensor systems, although external limiting and complete operating-limit checks remain necessary. Gain is set with one external resistor, simplifying calibration while preserving flexibility across load-cell, pressure, and force measurements.
Recommended
Industrial Data Acquisition
INA129A is appropriate for industrial measurement systems that combine sensor wiring, analog-to-digital conversion, and diagnostic control. The current-feedback input architecture maintains 200 kHz bandwidth at gain 100, while the precision offset and drift figures help preserve small-signal accuracy over temperature changes. A practical implementation places the amplifier close to the connector or bridge, uses shielded or differential routing, and supplies local decoupling. Engineers should verify the complete common-mode range, output swing, gain resistor tolerance, and protection network against the intended industrial input range.
Recommended
Biomedical Instrumentation
The INA129A can be used in biomedical and diagnostic instrumentation when a low-level differential sensor signal requires accurate amplification and common-mode suppression. Low input bias current of 5 nA maximum helps limit loading on high-impedance sources, while low offset voltage and drift support accurate measurement of small physiological or biochemical signals. The wide ±18 V supply capability is useful for bipolar sensor-bias arrangements. Medical designs still require application-specific isolation, leakage analysis, patient-safety review, and compliance verification; none of those requirements is established by the supplied data.
Recommended
Audio and Communication Amplification
INA129A is usable in audio and communication equipment when a balanced input must be amplified while rejecting equal-mode interference. Its high common-mode rejection can improve immunity to shared ground or cable-induced voltage, and the 200 kHz bandwidth at gain 100 provides useful signal bandwidth for many communication paths. The current-feedback input stage is particularly attractive when the system needs bandwidth that remains useful at higher closed-loop gains. Audio designs should still account for noise density, output drive, supply ripple, distortion, and the actual signal bandwidth, none of which is fully quantified in the supplied verified data.
Recommended
Power and Motor Monitoring
INA129A can condition differential voltage signals in power-supply, motor-drive, and current-sense monitoring systems when the common-mode voltage is within the device's operating limits. Low offset voltage and low input bias current are useful for preserving small measurement signals, while the instrumentation-amplifier topology simplifies differential input conditioning. The ±40 V input protection rating should be treated as a design starting point rather than a standalone safety guarantee; use appropriate series resistance, clamping, filtering, and fault analysis for inductive or high-energy nodes.
Recommended
Test and Measurement Equipment
INA129A fits precision test and measurement front ends that must amplify a differential probe or sensor signal while rejecting common-mode probe noise. Its 50 µV maximum offset voltage, 0.5 µV/°C maximum drift, and 120 dB minimum CMR support accurate small-signal conditioning. The 8-pin SOIC format supports compact analog boards, while the external gain resistor permits calibration-friendly gain selection. In production test equipment, evaluate input capacitance, cable-length stability, grounding, shielding, output filtering, and calibration drift before finalizing the analog path.
Recommended
Recommended Products Summary
Engineering reference data for INA129A — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | INA129UA | INA128 | INA129PA |
|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
Key Differentiators
- High-gain bandwidth (vs INA129UA)
- Precision offset performance (vs INA128)
- Input protection and low bias (vs INA129PA)
Design Notes
Keep the INA129A input and feedback paths short and place the external gain-setting resistor close to the gain pins. The current-feedback input architecture benefits from a clean, low-parasitic feedback path, especially at higher gain values. Route differential inputs away from switching nodes and high-current power traces; use a continuous ground plane and avoid splitting the analog ground return beneath the amplifier.
Treat the ±40 V input-protection figure as a verified feature, not as permission to remove external protection. Add series resistance, input filtering, and clamp components where sensor wiring or inductive transients can exceed normal operating conditions. Verify the final design against the complete absolute-maximum and recommended operating information in the manufacturer datasheet.
Place local supply-decoupling capacitors close to the power pins and preserve the intended ground return path. The verified data specifies a wide ±18 V supply range, but does not provide current, dropout, output-swing, or power-consumption values for this exact MPN. Calculate dissipation from the actual supply voltage, output voltage, load current, and quiescent current before sizing copper or thermal provisions.
Do not assume that INA129, INA128, and every INA129 ordering code has identical production behavior. Confirm the exact suffix, package, pin functions, gain implementation, temperature range, and electrical limits before substituting an alternative. Also verify the gain resistor equation and tolerance; precision CMRR and low offset specifications cannot compensate for incorrect pin connections or unsuitable common-mode operation.
Compliance Information
The supplied verified data does not explicitly state RoHS, REACH, lead-free, halogen-free, or conflict-minerals status. INA129A is an integrated circuit, so AEC-Q100 qualification is not established and is recorded as not_applicable only as a compliance-field status; it should not be interpreted as an automotive qualification claim.