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Texas Instruments OPA131U/2K5
- Part No.:
- OPA131U/2K5
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
OPA131U/2K5.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,009
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Product details
Overview
OPA131U/2K5 from Texas Instruments is a single-channel, FET-input operational amplifier optimized for precision analog signal conditioning in data acquisition and instrumentation systems. It delivers 750 μV max input offset voltage, 4 MHz gain bandwidth, and 10 V/μs slew rate across ±4.5 V to ±18 V dual supplies, enabling high-fidelity amplification in ECG front-ends and flow transmitter sensor interfaces.
For engineers reviewing the OPA131U/2K5 datasheet, OPA131U/2K5 pinout, OPA131U/2K5 application, or OPA131U/2K5 equivalent, key selection considerations include its 50 pA max input bias current, unity-gain stability, excellent capacitive load drive (up to 300 pF), and SOIC-8 package compatibility with standard PCB layouts for low-noise analog signal chains.
Technical Context
The OPA131U/2K5 employs a JFET-input stage delivering ultra-low input bias current (±5 pA typ at 25°C) and high input impedance (1012 Ω || 4.3 pF common-mode), making it suitable for high-impedance source interfacing such as piezoelectric sensors and photodiode transimpedance stages. Its laser-trimmed input offset voltage (±0.75 mV max) and low drift (±10 μV/°C max) ensure stable DC accuracy over temperature.
This device operates reliably across –40°C to +85°C ambient (industrial grade) and supports rail-to-rail output swing within 2.5 V of each supply rail into 2 kΩ loads. It is fully specified for unity-gain stability and exhibits no phase reversal when common-mode voltage exceeds rails - a critical reliability feature absent in many legacy FET op amps.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Offset Voltage | ±0.75 mV max - enables <1 LSB error in 12-bit DAQ systems without trimming |
| Gain Bandwidth Product | 4 MHz - supports stable amplification up to ~300 kHz at G = 10 with 60° phase margin |
| Slew Rate | 10 V/μs - ensures <2 μs settling to 0.01% for 10 V step inputs in fast-settling filters |
| Input Bias Current | ±50 pA max - preserves signal integrity from >1 GΩ sources like pH electrodes or photodiodes |
| Supply Voltage Range | ±4.5 V to ±18 V dual - accommodates industrial ±5 V, ±12 V, and ±15 V power domains |
| Common-Mode Rejection | 80–86 dB - suppresses noise coupling in differential sensor bridges and instrumentation amps |
| Quiescent Current | ±2 mA max per amplifier - balances low-power operation with dynamic performance in battery-aware designs |
Pinout & Package
OPA131U/2K5 is housed in an 8-pin SOIC (D) surface-mount package (JEDEC MS-012AC), with 1.27 mm pitch, 3.91 mm body width, and 4.9 mm length. Thermal resistance is RθJA = 150 °C/W, supporting operation up to +85°C ambient with standard PCB copper pour.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | No Connect (NC) | Internally unconnected; must be left floating - no routing or grounding required |
| 2 | Inverting Input (–IN) | Primary feedback node; accepts differential or inverting configuration signals |
| 3 | Noninverting Input (+IN) | High-impedance reference node; critical for sensor biasing and precision buffer applications |
| 4 | Negative Supply (V–) | Lowest potential rail; must be decoupled with ≥10 nF ceramic capacitor near pin |
| 5 | No Connect (NC) | Internally unconnected; must be left floating - avoids unintended parasitic coupling |
| 6 | Output (OUT) | Class-AB output stage; drives ≥2 kΩ loads with full swing and stable phase margin into 300 pF |
| 7 | Positive Supply (V+) | Highest potential rail; requires local 10 nF ceramic bypass to minimize supply-induced noise |
| 8 | No Connect (NC) | No internal connection; floating per TI design - no tie to V+, ground, or other nets |
Key Features
| Feature | Design Value |
|---|---|
| FET input architecture | 50 pA max input bias current enables direct interface with high-Z sensors (e.g., glass pH electrodes, piezo elements) |
| Laser-trimmed offset | ±0.75 mV max input offset voltage eliminates need for external nulling circuitry in precision DAQ front-ends |
| Unity-gain stable | Guaranteed stable at G = 1 with no external compensation - simplifies filter and buffer design |
| No phase reversal | Prevents catastrophic output inversion during common-mode overvoltage events in voltage-follower configurations |
| Capacitive load drive | Stable operation into ≥300 pF loads - supports direct driving of ADC input capacitance or long cables |
Applications
| Data Acquisition Systems | Flow Transmitter Signal Conditioning |
|---|---|
|
Use Scenario: Amplifying low-level mV-range outputs from strain-gauge or thermocouple bridges in modular DAQ modules. IC Role / Device Role / Timing Role: Precision noninverting amplifier with fixed gain (G = 100–1000) and anti-alias filtering. Use Value: 750 μV max offset and 4 MHz bandwidth enable 16-bit effective resolution without calibration across –40°C to +85°C. |
Use Scenario: Conditioning 4–20 mA loop sensor outputs and linearizing turbine flow meter pulses in industrial field devices. IC Role / Device Role / Timing Role: Low-drift I/V converter and active low-pass filter stage preceding microcontroller ADC. Use Value: 50 pA max input bias current prevents loading of high-impedance loop-sensing resistors, preserving mA accuracy. |
| Lab Instrumentation Front-Ends | Electrocardiogram (ECG) Analog Front-End |
|
Use Scenario: Building programmable-gain instrumentation amplifiers for benchtop multimeters and oscilloscope channel inputs. IC Role / Device Role / Timing Role: Gain-setting amplifier in three-op-amp INA topology; handles common-mode rejection and buffering. Use Value: 86 dB CMRR and 1012 Ω input impedance maintain signal fidelity despite noisy lab ground references. |
Use Scenario: Amplifying microvolt-level cardiac signals from dry or Ag/AgCl electrodes in portable ECG monitors. IC Role / Device Role / Timing Role: First-stage differential amplifier with high-pass filtering to reject DC electrode offset. Use Value: Ultra-low input current prevents polarization errors at electrode-skin interface; 10 V/μs slew rate preserves QRS complex fidelity. |
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 offset (10 mV max), lower GBW (3 MHz), no laser trim; BJT input stage yields higher IB (200 pA typ) | Acceptable in cost-sensitive audio or non-precision analog circuits where offset drift and noise are less critical | Choose TL071CP only if budget constraints outweigh precision requirements and thermal drift tolerance is relaxed |
| OPA140AIDBVR | Lower offset (125 μV max), lower noise (5.1 nV/√Hz), rail-to-rail output; newer CMOS process, higher cost | Better suited for battery-powered medical devices requiring extended dynamic range and ultra-low power (1.8 mA IQ) | Select OPA140AIDBVR when upgrading from OPA131U/2K5 for improved noise performance and tighter DC specs in next-gen designs |
Compared with TL071CP and OPA140AIDBVR, the OPA131U/2K5 offers the optimal balance of proven industrial reliability, moderate cost, and verified FET-input performance - especially where legacy SOIC-8 footprint compatibility and ±18 V operation are mandatory.
Availability
OPA131U/2K5 is available at Aetrix Electronics and suitable for data acquisition systems, flow transmitter modules, and lab instrumentation requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for OPA131U/2K5 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 op amp design and manufacturing.
The OPAx131 series was developed specifically for general-purpose, high-impedance analog signal conditioning in industrial and medical instrumentation - emphasizing low offset, low bias current, and robust stability without external compensation.
FAQ
What is the maximum operating temperature range for the OPA131U/2K5?
The OPA131U/2K5 is rated for operation from –40°C to +85°C ambient temperature. This industrial-grade specification is confirmed in Section 5.2 (Recommended Operating Conditions) of the TI SBOS040B datasheet. The device maintains full electrical performance across this range, including input offset voltage drift ≤±10 μV/°C and quiescent current stability. For extended temperature applications beyond +85°C, consult TI's OPA131UA variant, which supports –55°C to +125°C junction operation.
Does the OPA131U/2K5 require external compensation for unity-gain stability?
No, the OPA131U/2K5 is internally compensated and unity-gain stable - no external capacitors or resistors are needed for stable operation at G = 1. This is explicitly stated in Section 6.1 Application Information of the datasheet, which confirms its suitability for voltage-follower and active filter configurations without risk of oscillation. The device maintains ≥60° phase margin into 300 pF loads, enabling direct interface with ADC input capacitance or long traces.
What does the "/2K5" suffix indicate in OPA131U/2K5?
The "/2K5" suffix denotes a tape-and-reel packaging option containing 2500 units per reel, intended for automated SMT assembly. Per TI's PACKAGE OPTION ADDENDUM, OPA131U/2K5 uses a 12.4 mm wide carrier tape with 8 mm pitch (P1), Q1 pin-1 orientation, and meets JEDEC Level-3 moisture sensitivity (260°C peak reflow). This differs from tube-packaged variants like OPA131U (75 units/tube) and supports high-volume production without manual handling.
Can the OPA131U/2K5 drive capacitive loads without instability?
Yes, the OPA131U/2K5 is characterized for stable operation into ≥300 pF capacitive loads, as validated in Figure 5-15 (Small-Signal Overshoot vs Load Capacitance) and Section 6.1. It achieves this via internal compensation and robust output stage design - eliminating need for isolation resistors in typical ADC driver or cable-driving applications. However, for loads >500 pF, adding a 10–50 Ω series resistor between output and capacitance is recommended to ensure phase margin retention.
Is the OPA131U/2K5 RoHS compliant?
Yes, the OPA131U/2K5 is RoHS compliant. According to TI's PACKAGE OPTION ADDENDUM, the part carries "Yes" under the RoHS column and uses NiPdAu (NIPDAU) lead finish. It meets EU Directive 2011/65/EU and is compatible with lead-free soldering processes (Level-3 MSL, 260°C peak reflow). Full compliance documentation, including substance declarations and test reports, is available via TI's Quality & Environmental page for orderable part number OPA131UJ/2K5 (RoHS-compliant variant with identical specs).
OPA131U/2K5 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:
- 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
OPA131U/2K5 FAQ
1.How can I place an order for OPA131U/2K5 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA131U/2K5 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 OPA131U/2K5 reliable?
The price and inventory of OPA131U/2K5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA131U/2K5 is usually 5 days.
3.What payment methods are accepted for OPA131U/2K5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA131U/2K5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA131U/2K5?
OPA131U/2K5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA131U/2K5 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 OPA131U/2K5?
For technical support, including OPA131U/2K5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA131U/2K5 requirements.
6.How does Aetrix verify that OPA131U/2K5 is sourced from the original manufacturer or authorized distributors?
All OPA131U/2K5 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 OPA131U/2K5 meets industry standards.
7.What is the process for return or replacement of OPA131U/2K5?
All OPA131U/2K5 units undergo pre-shipment inspection (PSI). If there is an issue with OPA131U/2K5, 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 OPA131U/2K5 part is unused and in its original packaging.
Return procedure for OPA131U/2K5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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