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Texas Instruments INA129UA
- Part No.:
- INA129UA
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
INA129UA.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:5,433
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Product details
Overview
INA129UA from Texas Instruments is a precision, low-power instrumentation amplifier designed for high-accuracy differential signal conditioning in noisy industrial environments. It delivers 50 μV max offset voltage, 0.5 μV/°C max drift, 1.3 MHz bandwidth at G = 1, 120 dB min CMRR, and ±40 V input overvoltage protection - enabling reliable operation in pressure transmitters, ECG front-ends, and weigh-scale analog signal chains.
For engineers reviewing the INA129UA datasheet, INA129UA pinout, INA129UA application, or INA129UA equivalent, this page provides verified technical context, validated pin functions, real-world application mappings, and two confirmed alternative parts with documented functional and application-level differences - all specific to the INA129UA (SOIC-8, CSO: FRE variant).
Technical Context
The INA129UA implements a three-op-amp architecture with current-feedback input stages, enabling stable 200 kHz bandwidth even at G = 100. Its gain is set by a single external resistor using the equation G = 1 + 49.4 kΩ/RG, optimized for drop-in replacement of legacy devices requiring that exact resistor ratio.
Input stage overvoltage protection clamps ±40 V faults without damage, while laser-trimmed thin-film resistors ensure 120 dB CMRR at G ≥ 100 and 0.5 μV/°C max offset drift across –40°C to +85°C. Quiescent current remains fixed at ±700 μA regardless of gain or supply voltage within ±2.25V to ±18V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Offset voltage | 50 μV maximum (RTI) - ensures ≤0.5 mV error at G = 100 before calibration |
| CMRR | 120 dB minimum at G = 100 - rejects >1 V common-mode interference as <10 μV error |
| Bandwidth | 1.3 MHz at G = 1 - supports >100 kHz sensor signals without attenuation |
| Input bias current | 0.7 nA maximum (CSO: FRE) - enables use with >1 MΩ source impedances without significant DC error |
| Supply range | ±2.25V to ±18V - operates from low-voltage battery rails up to industrial ±15V systems |
| Quiescent current | 700 μA - draws <1.5 mW from ±5V supplies, suitable for portable instrumentation |
| Noise density | 8 nV/√Hz at 1 kHz - contributes <1.2 μVRMS integrated noise in 10 kHz bandwidth |
Pinout & Package
INA129UA is supplied in an 8-pin SOIC (D package), 4.9 mm × 6 mm body, with standard JEDEC MS-012AC footprint and 1.27 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RG (Gain resistor terminal) | Connects one end of external gain-setting resistor; forms G = 1 + 49.4 kΩ/RG with Pin 8 |
| 2 | VIN– | Inverting input; high-impedance node (100 GΩ || 9 pF) with ±40 V fault tolerance |
| 3 | VIN+ | Non-inverting input; matched to VIN– for optimal CMRR and low input offset current |
| 4 | V– | Negative power supply rail; must be decoupled locally for noise-sensitive applications |
| 5 | REF | Output reference node; drives output offset; requires low-impedance connection (≤8 Ω) for full CMRR |
| 6 | VO | Differential output; swings to within 1.4 V of rails (CSO: SHE) or 0.15 V (CSO: FRE) under load |
| 7 | V+ | Positive power supply rail; supports single-supply operation up to 36 V (V+ to GND) |
| 8 | RG (Gain resistor terminal) | Connects other end of external gain-setting resistor; completes gain network with Pin 1 |
Key Features
| Feature | Design Value |
|---|---|
| Laser-trimmed gain equation | G = 1 + 49.4 kΩ/RG enables direct replacement of legacy IAs without recalculating RG |
| Input overvoltage protection | ±40 V fault tolerance on VIN+ and VIN– prevents latch-up or damage in field-deployed sensors |
| Low-drift offset | 0.5 μV/°C max drift ensures <2 μV total offset shift across –40°C to +85°C operating range |
| High CMRR at high frequency | 120 dB CMRR maintained up to 10 kHz (G = 100) - critical for rejecting 50/60 Hz mains interference |
| Single-supply compatibility | Operates from 4.5 V to 36 V single supply - eliminates need for dual-rail generation in portable DAQ |
Applications
| Pressure Transmitter | Electrocardiogram (ECG) |
|---|---|
Use Scenario: Amplifies mV-level bridge output from piezoresistive pressure sensors in HVAC or process control systems, where common-mode voltages exceed ±10 V due to long cable runs. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing gain, common-mode rejection, and input protection before ADC sampling. Use Value: 120 dB CMRR suppresses induced 50/60 Hz noise; ±40 V input protection prevents field failures from transient surges on 24 V loop-powered lines. |
Use Scenario: Front-end amplification of microvolt-level differential cardiac signals from RA-LA/LL leads, immersed in high-noise clinical environments with electrosurgical units. IC Role / Device Role / Timing Role: First-stage IA delivering programmable gain (G = 100–500) and high input impedance to preserve signal fidelity before filtering and digitization. Use Value: 0.7 nA max input bias current minimizes electrode polarization errors; 8 nV/√Hz noise ensures clean ST-segment visualization without averaging. |
| Weigh Scale | Analog Input Module |
Use Scenario: Conditioned output from 350 Ω strain-gauge bridges in platform scales, where temperature drift and mechanical vibration induce common-mode shifts. IC Role / Device Role / Timing Role: Low-drift IA converting bridge imbalance into robust single-ended voltage referenced to system ground. Use Value: 0.5 μV/°C max offset drift limits zero-point drift to <1 LSB in 16-bit systems over 40°C ambient change; laser trimming ensures repeatability across production lots. |
Use Scenario: Universal analog input channel in PLC or DCS modules accepting ±10 V, 4–20 mA, or thermocouple inputs via configurable front-end networks. IC Role / Device Role / Timing Role: Reconfigurable gain block supporting multiple sensor types through software-selected RG values. Use Value: Single-resistor gain programming (G = 1–10,000) simplifies BOM management; ±18 V supply range accommodates industrial ±15 V rails and isolated sensing domains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA128UA | Uses G = 1 + 50 kΩ/RG; 5 nA max input bias current (CSO: SHE); 125 dB CMRR at G = 100 | Better CMRR and lower noise floor, but higher input bias current reduces accuracy with high-Z sources | Select INA128UA when ultimate CMRR (>120 dB) and lowest possible noise are required, and source impedance is <100 kΩ |
| INA828IDR | 0.6 nA max input bias current; 7 nV/√Hz noise; same 700 μA quiescent current; G = 1 + 50 kΩ/RG | Superior input bias and noise specs, but requires layout revision due to different pinout (Ref on Pin 5 vs Pin 5 on INA129UA) | Select INA828IDR for next-generation designs prioritizing ultra-low bias current and noise, accepting non-drop-in layout change |
Compared with INA129UA, INA128UA offers higher CMRR but higher input bias current, making it less suitable for high-impedance sensors; INA828IDR improves both bias and noise but requires PCB redesign due to incompatible pin mapping and gain equation - neither is pin-compatible, but both serve overlapping precision measurement roles.
Availability
INA129UA is available at Aetrix Electronics and suitable for pressure transmitter design, ECG front-end development, and industrial analog input module production requiring stable component supply and long-term manufacturability.
Supply support for INA129UA includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of heritage in precision signal chain components.
The INA12x family - including INA129UA - was engineered for industrial and medical instrumentation demanding low drift, high CMRR, and rugged input protection in space- and power-constrained systems.
FAQ
What is the gain equation for INA129UA, and how does it differ from INA128UA?
The INA129UA uses the gain equation G = 1 + 49.4 kΩ/RG, where RG is connected between Pins 1 and 8. This differs from the INA128UA's G = 1 + 50 kΩ/RG. The 49.4 kΩ coefficient enables direct drop-in replacement of certain legacy instrumentation amplifiers without recalculating RG. Both equations yield identical gain values only when RG is adjusted accordingly - e.g., 49.4 kΩ for G = 2 on INA129UA versus 50 kΩ on INA128UA. The INA129UA datasheet confirms this ratio applies specifically to the UA-grade device.
Does INA129UA support single-supply operation, and what is the minimum supply voltage?
Yes, INA129UA supports true single-supply operation from 4.5 V to 36 V (V+ to GND). The minimum dual-supply voltage is ±2.25 V, meaning it operates down to ±2.25V or 4.5 V total span. At V+ = 5 V and V– = 0 V, the input common-mode range extends from 2 V to 3 V (V– + 2 V to V+ – 2 V), and output swing reaches within 1.4 V of each rail (CSO: SHE) or 0.15 V (CSO: FRE). This makes INA129UA suitable for battery-powered data loggers and 5 V industrial I/O modules.
What is the maximum input overvoltage the INA129UA can withstand without damage?
The INA129UA input terminals (VIN+ and VIN–) are protected to ±40 V relative to the V– supply rail, regardless of whether operated on single or dual supplies. This rating is absolute - not dependent on gain or output loading - and is validated per TI's internal stress testing. The protection circuitry clamps transient overvoltages without latch-up or parametric shift, preserving functionality after events such as 24 V loop wiring misconnections or ESD discharge. This specification is explicitly stated in Section 6.1 Absolute Maximum Ratings of the INA129UA datasheet.
How does the CSO (Chip Site Origin) affect INA129UA performance specifications?
INA129UA is manufactured across two qualified fabrication flows: CSO: FRE and CSO: SHE. For the UA grade, CSO: FRE specifies 0.7 nA max input bias current and 0.15–0.6 nA typical, while CSO: SHE specifies 5 nA max. Similarly, noise is 6.9 nV/√Hz (FRE) vs 8 nV/√Hz (SHE) at 1 kHz. TI qualifies both flows to full datasheet limits, and system designs must meet specifications across all CSOs. The "UA" suffix denotes the highest-grade screening, and all published min/typ/max values in the INA129UA datasheet reflect worst-case bounds across both CSOs unless otherwise noted.
Can INA129UA drive capacitive loads, and what is the maximum stable load capacitance?
INA129UA is stable driving capacitive loads up to 1000 pF, as specified in the Electrical Characteristics table (Section 6.5). This allows direct interface with anti-aliasing filters, ADC input capacitors, or long PCB traces without external isolation resistors. Stability is maintained across all gains (G = 1 to 10,000) and supply voltages (±2.25V to ±18V). For loads exceeding 1000 pF, TI recommends adding a small series resistor (e.g., 10–50 Ω) between VO and the capacitor to preserve phase margin - a technique validated in Figure 8-3 of the INA129UA datasheet.
INA129UA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- Instrumentation
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 4V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 1.3 MHz
- Current - Input Bias:
- 2 nA
- Voltage - Input Offset:
- 25 µV
- Current - Supply:
- 700µA
- Current - Output / Channel:
- 15 mA
- Voltage - Supply Span (Min):
- 4.5 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
INA129UA FAQ
1.How can I place an order for INA129UA through Aetrix?
Please submit a Request for Quotation (RFQ) for INA129UA on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for INA129UA reliable?
The price and inventory of INA129UA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA129UA is usually 5 days.
3.What payment methods are accepted for INA129UA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA129UA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA129UA?
INA129UA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA129UA order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for INA129UA?
For technical support, including INA129UA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA129UA requirements.
6.How does Aetrix verify that INA129UA is sourced from the original manufacturer or authorized distributors?
All INA129UA products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that INA129UA meets industry standards.
7.What is the process for return or replacement of INA129UA?
All INA129UA units undergo pre-shipment inspection (PSI). If there is an issue with INA129UA, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The INA129UA part is unused and in its original packaging.
Return procedure for INA129UA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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