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Texas Instruments INA128UA/2K5G4
- Part No.:
- INA128UA/2K5G4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
INA128UA/2K5G4.pdf
- Description:
- IC INST AMP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,571
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Product details
Overview
INA128UA/2K5G4 from Texas Instruments is a precision, low-power instrumentation amplifier designed for high-accuracy differential signal conditioning in noisy industrial and medical environments. It delivers 50 μV maximum offset voltage, 120 dB minimum CMRR at G = 100, 1.3 MHz bandwidth (G = 1), ±40 V input overvoltage protection, and operates from ±2.25 V to ±18 V dual supplies. It is widely deployed in pressure transmitters and ECG front-ends where dc accuracy and common-mode rejection are critical.
For engineers reviewing the INA128UA/2K5G4 datasheet, INA128UA/2K5G4 pinout, INA128UA/2K5G4 application, or INA128UA/2K5G4 equivalent, key selection criteria include verified gain-setting resistor compatibility (50 kΩ for G = 1 + 50 kΩ/RG), SOIC-8 package thermal performance (RθJA = 110 °C/W), CSO-specific bias current limits (0.7 nA max for FRE site), and confirmed operation across –40°C to +85°C.
Technical Context
The INA128UA/2K5G4 implements a three-op-amp architecture with current-feedback input stages, enabling stable 200 kHz bandwidth even at G = 100. Its laser-trimmed thin-film resistors ensure precise gain equation fidelity (G = 1 + 50 kΩ/RG) and low drift (0.5 μV/°C max).
Input overvoltage protection circuitry clamps ±40 V faults without damage, while the REF pin allows output level shifting relative to ground or system reference-critical for single-supply DAQ interfacing. The device is specified only for the FRE chip site origin, confirming 0.7 nA max input bias current and 6.9 nV/√Hz voltage noise at 1 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Offset voltage | 50 μV maximum (RTI) - ensures ≤0.5 mV error at G = 100 with ±10 mV input |
| CMRR | 120 dB minimum at G = 100 - rejects ≥1 V common-mode interference as <1 μV error |
| Bandwidth | 1.3 MHz at G = 1 - supports >650 kHz sine-wave acquisition before –3 dB roll-off |
| Input bias current | 0.7 nA maximum (CSO: FRE) - enables use with >1 MΩ sensor source impedances without significant offset shift |
| Supply range | ±2.25 V to ±18 V - operates from low-voltage battery rails up to industrial ±15 V systems |
| Quiescent current | 700 μA - draws <1.4 mW from ±5 V supplies, suitable for portable instrumentation |
| Input overvoltage | ±40 V - survives transient surges beyond supply rails without latch-up or parametric shift |
Pinout & Package
INA128UA/2K5G4 is housed in an 8-pin SOIC (D) package measuring 4.9 mm × 6 mm, optimized for surface-mount assembly and thermal dissipation (RθJA = 110 °C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 8 | RG (Gain resistor terminals) | Connect external resistor between pins 1 and 8 to set gain per G = 1 + 50 kΩ/RG; open-circuit yields G = 1 |
| 2 | VIN– | Inverting input - accepts differential signal referenced to VIN+; protected to ±40 V |
| 3 | VIN+ | Non-inverting input - high-impedance (10 GΩ || 2 pF) node for precision sensor connection |
| 4 | V– | Negative supply rail - must be connected to system ground or negative supply; decoupling required |
| 5 | REF | Output reference - sets DC level of VO; low-impedance connection essential for CMRR integrity |
| 6 | VO | Amplified output - swing limited to (V–) + 1.4 V / (V+) – 1.4 V (CSO: SHE) or (V–) + 0.15 V / (V+) – 0.15 V (CSO: FRE) |
| 7 | V+ | Positive supply rail - supports wide-range dual or single-supply operation; requires local 0.1 μF bypass |
Key Features
| Feature | Design Value |
|---|---|
| Laser-trimmed gain network | Ensures ±0.025% gain error at G = 10 and ±0.15% at G = 1000 (CSO: FRE), eliminating calibration for mid-gain industrial sensors |
| Current-feedback input stage | Maintains 200 kHz bandwidth at G = 100 - enables accurate high-speed strain gauge or thermocouple measurements |
| Overvoltage-protected inputs | Withstands ±40 V faults indefinitely without parameter shift - eliminates need for external clamping diodes in field-connected transmitters |
| Low 0.1–10 Hz noise | 0.2 μVPP - provides superior resolution for slow-varying physiological signals like ECG ST-segment analysis |
| Single-supply compatible REF pin | Allows output offset adjustment to match ADC input range (e.g., 0–2.5 V), reducing need for level-shifting circuitry |
Applications
| Pressure Transmitter | Temperature Transmitter |
|---|---|
Use Scenario: Amplifying mV-level bridge output from piezoresistive pressure sensors in HVAC or process control. IC Role / Device Role / Timing Role: Precision instrumentation amplifier providing fixed G = 100–500 gain with <1 μV/°C drift to maintain calibration over ambient temperature swings. Use Value: Enables direct interface to 16-bit SAR ADCs without additional offset trimming, reducing BOM count and calibration labor. |
Use Scenario: Conditioning output from Pt100 RTDs or thermistor networks in industrial ovens and chillers. IC Role / Device Role / Timing Role: Differential amplifier rejecting lead-wire noise and common-mode pickup in 3-wire or 4-wire configurations. Use Value: Delivers 0.1°C measurement resolution over –40°C to +125°C using only passive gain-setting resistor and no active compensation. |
| Weigh Scale | Electrocardiogram (ECG) |
Use Scenario: Reading microvolt-level signals from load cell Wheatstone bridges in platform scales and industrial weigh modules. IC Role / Device Role / Timing Role: Low-noise, high-CMRR front-end amplifier rejecting 50/60 Hz mains interference and RF coupling from nearby motors. Use Value: Achieves <1 μVPP input-referred noise floor at 10 Hz, supporting 20,000:1 dynamic range for sub-gram resolution. |
Use Scenario: Biopotential amplification in portable or bedside ECG monitors with dry or Ag/AgCl electrodes. IC Role / Device Role / Timing Role: First-stage IA rejecting electrode half-cell potentials and power-line interference while preserving QRS morphology. Use Value: 120 dB CMRR at 60 Hz and 0.2 μVPP 0.1–10 Hz noise enable clean R-wave detection without digital filtering artifacts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA128U | Same die, identical electrical specs, but in PDIP-8 package (9.81 mm × 9.43 mm); higher RθJA (46.1 °C/W) | Suitable for prototyping or through-hole production; not recommended for high-density PCBs or thermally constrained enclosures | Select INA128U only when manual soldering or socket-based validation is required; INA128UA/2K5G4 preferred for volume SMT manufacturing. |
| INA828IDR | Lower input bias current (0.6 nA max), lower noise (7 nV/√Hz), same quiescent current; uses same 50 kΩ gain equation | Better suited for ultra-high-impedance pH or ion-selective electrodes; slightly higher cost and newer qualification status | Choose INA828IDR when bias current <0.65 nA is mandatory; INA128UA/2K5G4 remains optimal for cost-sensitive, established designs requiring proven field reliability. |
Compared with INA128U and INA828IDR, the INA128UA/2K5G4 offers the best balance of legacy design support, SOIC-8 manufacturability, and verified performance across –40°C to +85°C - making it ideal for industrial analog input modules where long-term supply continuity and thermal robustness are prioritized over marginal noise or bias current improvements.
Availability
INA128UA/2K5G4 is available at Aetrix Electronics and suitable for pressure transmitter design, ECG front-end development, and weigh scale signal conditioning requiring stable component supply across multi-year production cycles.
Supply support for INA128UA/2K5G4 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 expertise in precision signal chain solutions.
The INA128 series belongs to TI's precision instrumentation amplifier product line, engineered specifically for high-accuracy, low-drift differential measurement in industrial process control, medical diagnostics, and test equipment.
FAQ
What is the exact gain equation implemented by the INA128UA/2K5G4?
The INA128UA/2K5G4 implements the industry-standard gain equation G = 1 + 50 kΩ/RG, where RG is an external resistor connected between pins 1 and 8. This differs from the INA129's 49.4 kΩ coefficient and ensures drop-in compatibility with legacy designs specifying the INA128 family. Verified on all FRE-site production lots.
Does the INA128UA/2K5G4 support single-supply operation?
Yes - the INA128UA/2K5G4 operates from a single 4.5 V to 36 V supply. When used in single-supply mode, the REF pin must be biased to a stable mid-rail voltage (e.g., VS/2) to center the output swing; the device maintains full specifications including 120 dB CMRR and 1.3 MHz bandwidth under these conditions.
What is the maximum safe input voltage for the INA128UA/2K5G4 relative to its supply rails?
The INA128UA/2K5G4 inputs are protected to ±40 V regardless of supply voltage - meaning they withstand voltages from (V–) – 40 V to (V+) + 40 V without damage or parametric shift. This exceeds the absolute maximum supply rating (±18 V) and enables direct connection to unconditioned field wiring in industrial I/O modules.
How does chip site origin (CSO) affect the INA128UA/2K5G4's input bias current specification?
The INA128UA/2K5G4 is qualified exclusively for the FRE chip site origin, which guarantees a maximum input bias current of 0.7 nA (vs. 5 nA for SHE). This tighter spec is validated per TI's SBOS051G datasheet and directly impacts high-impedance sensor interfaces - for example, limiting error to <0.7 mV with a 1 MΩ source impedance at room temperature.
Can the INA128UA/2K5G4 drive a 10-kΩ load while maintaining full AC performance?
Yes - the INA128UA/2K5G4 is fully characterized into 10 kΩ loads per the datasheet (RL = 10 kΩ), delivering its rated 1.3 MHz bandwidth, 200 kHz at G = 100, and 0.2 μVPP low-frequency noise. Driving lower impedances (e.g., 2 kΩ) degrades bandwidth and increases distortion; consult Figure 6-22 for output swing vs. load current data.
INA128UA/2K5G4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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
INA128UA/2K5G4 FAQ
1.How can I place an order for INA128UA/2K5G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA128UA/2K5G4 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 INA128UA/2K5G4 reliable?
The price and inventory of INA128UA/2K5G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA128UA/2K5G4 is usually 5 days.
3.What payment methods are accepted for INA128UA/2K5G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA128UA/2K5G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA128UA/2K5G4?
INA128UA/2K5G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA128UA/2K5G4 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 INA128UA/2K5G4?
For technical support, including INA128UA/2K5G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA128UA/2K5G4 requirements.
6.How does Aetrix verify that INA128UA/2K5G4 is sourced from the original manufacturer or authorized distributors?
All INA128UA/2K5G4 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 INA128UA/2K5G4 meets industry standards.
7.What is the process for return or replacement of INA128UA/2K5G4?
All INA128UA/2K5G4 units undergo pre-shipment inspection (PSI). If there is an issue with INA128UA/2K5G4, 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 INA128UA/2K5G4 part is unused and in its original packaging.
Return procedure for INA128UA/2K5G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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