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Texas Instruments OPA131UA
- Part No.:
- OPA131UA
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
OPA131UA.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:589
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Product details
Overview
OPA131UA from Texas Instruments is a single-channel, FET-input operational amplifier designed for precision analog signal conditioning in data acquisition and instrumentation systems. It delivers 4MHz gain-bandwidth, 10V/μs slew rate, ±4.5V to ±18V dual-supply operation, and ≤750μV input offset voltage - enabling high-fidelity amplification of low-level sensor signals in ECG front-ends and flow transmitters.
For engineers reviewing the OPA131UA datasheet, OPA131UA pinout, OPA131UA application, or OPA131UA equivalent, key selection criteria include its 50pA max input bias current, unity-gain stability, excellent capacitive load drive (up to 300pF), and SOIC-8 package compatibility with industrial temperature range (–40°C to +85°C) and extended range (–55°C to +125°C) variants.
Technical Context
The OPA131UA employs a JFET-input stage delivering ultra-low input bias current (≤50pA) and high input impedance (10¹² Ω || 4.3pF common-mode), making it suitable for high-impedance source interfacing such as photodiode transimpedance amplifiers and pH electrode buffers. Its laser-trimmed input offset voltage (±0.75mV max) and low drift (±10μV/°C max) ensure stable DC accuracy across temperature.
This device is unity-gain stable and free from input common-mode–induced phase reversal - a critical reliability feature absent in many legacy FET op amps. It supports rail-to-rail output swing within 2.5V of each supply rail at 2kΩ load and maintains >94dB open-loop gain (min) over its full operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Bias Current | ≤50pA max - enables accurate amplification of nanoamp-level sensor currents without significant error. |
| Input Offset Voltage | ±0.75mV max - ensures <1 LSB error in 12-bit DAQ systems with ±5V full-scale range. |
| Gain Bandwidth Product | 4MHz - supports stable closed-loop gain ≥10 at 400kHz or unity-gain up to 4MHz. |
| Slew Rate | 10V/μs - allows clean 10Vpp output at 1.5MHz without slewing distortion. |
| Supply Voltage Range | ±4.5V to ±18V dual or 9V–36V single - accommodates industrial ±15V rails and battery-powered 12V/24V systems. |
| Common-Mode Rejection | ≥70dB - suppresses noise on differential sensor inputs with mismatched source impedances. |
| Quiescent Current | ±1.75mA max per amplifier - balances performance and power efficiency in multi-channel systems. |
Pinout & Package
OPA131UA is housed in an 8-pin SOIC (D package), surface-mount package with standard industry pinout. Thermal resistance is RθJA = 150°C/W, supporting operation up to +85°C ambient without forced airflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| +IN (Pin 3) | Noninverting input | High-impedance node for reference or signal input; accepts common-mode voltages from (V–)+3V to (V+)-3.5V. |
| –IN (Pin 2) | Inverting input | High-impedance feedback node; used in transimpedance, inverting amplifier, and active filter configurations. |
| OUT (Pin 6) | Output | Capable of sourcing/sinking ±20mA; swings to within 2.5V of either supply rail into 2kΩ load. |
| V+ (Pin 7) | Positive power supply | Highest potential rail; must be bypassed with ≥10nF ceramic capacitor near the pin. |
| V– (Pin 4) | Negative power supply | Lowest potential rail; requires identical local bypassing as V+ for PSRR optimization. |
| NC (Pins 1, 5, 8) | No internal connection | Must be left floating; no routing or grounding required - avoids unintended parasitic coupling. |
Key Features
| Feature | Design Value |
|---|---|
| FET input stage | 50pA max input bias current enables direct interface with high-Z sources like piezoelectric sensors and ion-selective electrodes. |
| Laser-trimmed offset | ±0.75mV max input offset voltage eliminates need for external nulling circuitry in precision DC-coupled stages. |
| Unity-gain stable | Operates reliably with gain = 1 without external compensation - simplifies filter and buffer design. |
| No phase reversal | Immune to output polarity inversion when input exceeds common-mode range - prevents latch-up in feedback loops. |
| Capacitive load drive | Stable with ≥300pF load capacitance - supports direct driving of ADC input capacitors and long PCB traces. |
Applications
| ECG Front-End Amplifier | Flow Transmitter Signal Conditioning |
|---|---|
|
Use Scenario: Amplifying microvolt-level biopotential signals from Ag/AgCl electrodes in portable ECG monitors. IC Role / Device Role / Timing Role: Primary low-noise, high-input-impedance instrumentation amplifier stage with DC-coupled gain. Use Value: 50pA input bias current prevents electrode polarization errors; 750μV offset ensures baseline stability across body temperature shifts. |
Use Scenario: Converting low-current outputs (e.g., 4–20mA loop or turbine meter pulses) into calibrated voltage signals in industrial flow meters. IC Role / Device Role / Timing Role: Precision current-to-voltage converter and anti-aliasing filter driver. Use Value: 4MHz bandwidth supports fast transient response to flow surges; excellent CMRR rejects common-mode noise from motor drives. |
| Data Acquisition Channel | Lab Instrumentation Buffer |
|
Use Scenario: Signal conditioning for 12–16-bit SAR ADCs in modular DAQ systems handling thermocouples, strain gauges, and RTDs. IC Role / Device Role / Timing Role: Input buffer and programmable-gain amplifier preceding multiplexer and ADC. Use Value: Low THD+N (0.0008%) preserves SNR; 10V/μs slew rate ensures accurate sampling of fast step inputs without distortion. |
Use Scenario: Isolating and scaling sensor outputs (e.g., pH probe, LVDT, or optical encoder) in benchtop multimeters and oscilloscope front-ends. IC Role / Device Role / Timing Role: High-impedance unity-gain buffer isolating sensitive DUTs from measurement circuitry. Use Value: 10¹² Ω input impedance prevents loading of high-Z sources; SOIC-8 footprint enables dense channel packing on instrument PCBs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET-input operational amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL071CP | Higher input bias current (30pA typ, but not specified max); wider offset voltage spread (±10mV max); lower GBW (3MHz). | Less suitable for ultra-high-impedance or low-drift DC applications; acceptable for AC-coupled audio or general-purpose gain stages. | Choose TL071CP only if cost sensitivity outweighs precision requirements and temperature drift is not critical. |
| OPA140AIDBVR | Lower input bias current (0.5pA typ), lower offset (±125μV max), higher GBW (11MHz), rail-to-rail output, but higher quiescent current (1.8mA). | Better for battery-powered portable instruments requiring lowest possible input error and wider bandwidth. | Select OPA140AIDBVR when sub-microvolt offset and femtoamp bias are mandatory; OPA131UA remains optimal for cost-sensitive industrial DAQ with ±15V supplies. |
Compared with TL071CP and OPA140AIDBVR, the OPA131UA delivers the best balance of low input bias, moderate bandwidth, proven industrial reliability, and SOIC-8 compatibility - making it ideal for fixed-supply, medium-precision instrumentation where layout simplicity and long-term supply continuity matter.
Availability
OPA131UA is available at Aetrix Electronics and suitable for data acquisition systems, flow transmitter modules, and lab instrumentation requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for OPA131UA 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 op amp design and manufacturing excellence.
The OPAx131 family was engineered specifically for cost-effective, high-performance general-purpose analog signal conditioning - targeting industrial, medical, and test equipment where FET-input precision meets robustness and broad supply flexibility.
FAQ
What is the maximum operating temperature range for the OPA131UA?
The OPA131UA is rated for operation from –40°C to +85°C ambient temperature. This extended industrial temperature range is confirmed in TI's official packaging addendum for the OPA131UA/2K5.B ordering variant, ensuring reliable performance in factory-floor and field-deployed instrumentation environments where thermal stress is present.
Does the OPA131UA require external compensation for unity-gain stability?
No, the OPA131UA is internally compensated and unity-gain stable. As stated in the TI datasheet Section 6.1, it does not require external compensation components - enabling straightforward use in voltage-follower, active filter, and transimpedance configurations without risk of oscillation.
Can the OPA131UA drive a 1000pF capacitive load?
The OPA131UA is characterized for stable operation with up to 300pF capacitive load (Figure 5-15). Driving 1000pF directly risks peaking or oscillation; a series resistor (e.g., 20–50Ω) between the OPA131UA output and the 1000pF load is required to maintain stability while preserving signal integrity.
What is the input common-mode voltage range for the OPA131UA at ±15V supply?
At ±15V supply, the OPA131UA supports an input common-mode voltage range from (V–)+3V = –12V to (V+)-3.5V = +11.5V. This 23.5V span allows robust operation with signals near either rail - critical for interfacing with sensors whose output floats relative to system ground.
Is the OPA131UA pin-compatible with other members of the OPAx131 family?
Yes - the OPA131UA shares the same 8-pin SOIC (D) package and pinout as the OPA2131 dual and OPA4131 quad versions. This allows drop-in replacement in single-amplifier positions and facilitates scalable design reuse across channel-count variants without PCB redesign.
OPA131UA 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:
- General Purpose
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 10V/µs
- Gain Bandwidth Product:
- 4 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 5 pA
- Voltage - Input Offset:
- 200 µV
- Current - Supply:
- 1.5mA
- Current - Output / Channel:
- 25 mA
- Voltage - Supply Span (Min):
- 9 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
OPA131UA FAQ
1.How can I place an order for OPA131UA through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA131UA 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 OPA131UA reliable?
The price and inventory of OPA131UA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA131UA is usually 5 days.
3.What payment methods are accepted for OPA131UA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA131UA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA131UA?
OPA131UA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA131UA 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 OPA131UA?
For technical support, including OPA131UA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA131UA requirements.
6.How does Aetrix verify that OPA131UA is sourced from the original manufacturer or authorized distributors?
All OPA131UA 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 OPA131UA meets industry standards.
7.What is the process for return or replacement of OPA131UA?
All OPA131UA units undergo pre-shipment inspection (PSI). If there is an issue with OPA131UA, 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 OPA131UA part is unused and in its original packaging.
Return procedure for OPA131UA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
OPA131UA Tags
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