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Texas Instruments OPA131U
- Part No.:
- OPA131U
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
OPA131U.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:194
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Product details
Overview
OPA131U from Texas Instruments is a single-channel, FET-input operational amplifier designed for precision analog signal conditioning in high-impedance sensor interfaces and instrumentation front-ends. It delivers 4MHz gain-bandwidth, 10V/μs slew rate, ±4.5V to ±18V dual-supply operation, ≤750μV input offset voltage (max), and 50pA max input bias current - enabling accurate low-level signal amplification in ECG, flow transmitter, and DAQ systems.
For engineers reviewing the OPA131U datasheet, OPA131U pinout, OPA131U application, or OPA131U equivalent, key selection considerations include its FET-input architecture for ultra-low IB, laser-trimmed offset stability over temperature, unity-gain stability with capacitive load drive capability, and SOIC-8 packaging compatible with industrial-grade ambient operating range (–40°C to +85°C).
Technical Context
The OPA131U employs a JFET-input differential pair to achieve femtoampere-level input bias current and high input impedance (10¹² Ω || 4.3 pF common-mode). Its internal compensation ensures unity-gain stability without external components, supporting robust performance in transimpedance, filter, and voltage-follower configurations.
It features rail-to-rail output swing within 2.5V of each supply rail at 2kΩ load, 110dB open-loop gain (min), and 80–86dB common-mode rejection ratio - optimized for DC-coupled precision circuits where offset drift (±2–±10 μV/°C) and PSRR (±50–±100 μV/V) directly impact measurement fidelity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Bias Current | ≤50 pA max - enables high-Z sensor interfacing (e.g., pH electrodes, piezoelectric transducers) without significant error current. |
| Input Offset Voltage | ≤750 μV max - supports sub-millivolt DC accuracy in 12-bit+ data acquisition without trimming. |
| Gain Bandwidth Product | 4 MHz - allows stable closed-loop gain ≥10 at 400 kHz or G=1 operation up to 4 MHz with minimal phase margin loss. |
| Slew Rate | 10 V/μs - sustains full-scale 10V step response in ≤1.5 μs (0.1% settling), suitable for fast pulse conditioning. |
| Supply Voltage Range | ±4.5 V to ±18 V - accommodates bipolar industrial supplies and legacy ±15V systems without level-shifting. |
| Quiescent Current | ±1.5 to ±2 mA per amplifier - balances low-power operation with dynamic performance in battery- or thermally constrained designs. |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments including field instrumentation and medical equipment enclosures. |
Pinout & Package
OPA131U 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 with moderate PCB copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| +IN (Pin 3) | Noninverting input | High-impedance node for reference or signal source connection; accepts common-mode voltage from (V–)+3V to (V+)-3.5V. |
| –IN (Pin 2) | Inverting input | Feedback node for closed-loop configurations; matched input capacitance minimizes CMRR degradation at high frequencies. |
| OUT (Pin 6) | Amplifier output | Capable of sourcing/sinking ±20 mA; swings to within 2.5V of rails into 2kΩ load for wide dynamic range. |
| V+ (Pin 7) | Positive power supply | Highest potential rail; must be bypassed with ≥10 nF ceramic capacitor near pin for stability and noise suppression. |
| V– (Pin 4) | Negative power supply | Lowest potential rail; same bypassing requirement as V+; defines lower common-mode and output swing limit. |
| NC (Pins 1, 5, 8) | No internal connection | Must be left floating - not tied to ground or supply; no electrical function or thermal benefit from connection. |
Key Features
| Feature | Design Value |
|---|---|
| FET input stage | 50 pA max input bias current enables direct interface with high-impedance sources (e.g., photodiodes, glass electrodes) without guard rings or bias compensation networks. |
| Laser-trimmed offset | ≤750 μV max VOS and ±10 μV/°C max drift ensure stable DC accuracy across industrial temperature range without manual calibration. |
| Unity-gain stable | No external compensation required - simplifies layout in voltage-follower, active filter, and transimpedance amplifier designs while maintaining phase margin >45°. |
| Capacitive load drive | Stable with ≥300 pF load capacitance - eliminates need for isolation resistors in driving ADC inputs or long cables in lab instrumentation. |
| No phase reversal | Immune to output polarity inversion when input common-mode exceeds rails - prevents catastrophic failure in control-loop feedback paths. |
Applications
| ECG Signal Conditioning | Flow Transmitter Amplification |
|---|---|
Use Scenario: Amplifying microvolt-level biopotential signals from electrode-skin interface with high common-mode noise rejection. IC Role / Device Role / Timing Role: Primary front-end instrumentation amplifier stage providing gain, filtering, and DC coupling before analog-to-digital conversion. Use Value: Ultra-low input bias current prevents electrode polarization errors; 86 dB CMRR suppresses 50/60 Hz interference without aggressive shielding. |
Use Scenario: Converting low-current output from magnetic flow meter sensors into calibrated voltage for PLC analog input modules. IC Role / Device Role / Timing Role: Transimpedance amplifier converting 4–20 mA loop current or µA-level sensor current into proportional voltage. Use Value: 4 MHz bandwidth supports fast flow transient detection; 10¹² Ω input impedance avoids loading sensor's current source output. |
| Data Acquisition Front-End | Lab Instrumentation Buffer |
Use Scenario: Driving multiplexer inputs or ADC sample-and-hold stages in modular DAQ systems requiring low distortion and fast settling. IC Role / Device Role / Timing Role: Precision buffer isolating high-impedance sensor outputs from switching transients and channel crosstalk. Use Value: 1.5 μs 0.1% settling time enables ≥500 kSPS sampling; 0.0008% THD+N preserves signal integrity for 16-bit resolution. |
Use Scenario: Providing low-output-impedance, high-fidelity buffering between function generator outputs and reactive DUT loads in benchtop test equipment. IC Role / Device Role / Timing Role: Unity-gain voltage follower ensuring signal fidelity and impedance transformation without phase shift or overshoot. Use Value: No phase reversal under overdrive prevents latch-up during signal clipping; 10 V/μs slew rate maintains waveform shape up to 100 kHz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET-input op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA140AIDBVR | Lower input bias current (0.5 pA typ), higher GBW (11 MHz), but narrower supply range (±4.5V to ±18V same; single-supply min 4.5V vs OPA131U's 9V). | Better for ultra-high-Z pH or radiation detector interfaces; less suitable for legacy ±12V systems due to lower VCM headroom. | Select OPA140AIDBVR when sub-picoampere IB is critical and supply rails support its VCM limits; otherwise OPA131U offers broader compatibility at lower cost. |
| TL071CP | Higher input bias current (30 pA typ, but 200 pA max), wider offset spread (±10 mV max), no laser trim, lower price. | Acceptable for non-critical audio or general-purpose amplification; unsuitable for precision DC-coupled measurement where offset drift dominates error budget. | Choose TL071CP only for cost-sensitive, AC-coupled, or non-precision applications; OPA131U provides guaranteed low-drift performance essential for industrial DAQ. |
Compared with OPA140AIDBVR and TL071CP, the OPA131U uniquely balances laser-trimmed DC precision, proven capacitive-load stability, and wide supply flexibility - making it the preferred choice for industrial instrumentation where reliability and specification compliance outweigh marginal GBW gains or cost reduction.
Availability
OPA131U is available at Aetrix Electronics and suitable for data acquisition systems, flow transmitter signal chains, and lab instrumentation requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for OPA131U 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 OPA131U belongs to TI's general-purpose FET-input op amp product line, engineered specifically for industrial and medical instrumentation where low input bias current, stable DC accuracy, and robust capacitive load drive are mandatory.
FAQ
What is the maximum input common-mode voltage range for the OPA131U?
The OPA131U supports an input common-mode voltage range from (V–) + 3 V to (V+) – 3.5 V under recommended operating conditions. For example, with ±15 V supplies, this spans –12 V to +11.5 V. Exceeding these limits may degrade CMRR or cause unexpected behavior, though the device avoids phase reversal - a known risk in older FET-input amplifiers.
Does the OPA131U require external compensation for unity-gain stability?
No, the OPA131U is internally compensated for unity-gain stability and operates reliably without external components across all gains. Its design ensures ≥45° phase margin even with 300 pF capacitive loads, eliminating the need for isolation resistors or feedback network adjustments in voltage-follower or transimpedance configurations.
What is the typical quiescent current consumption of the OPA131U?
The OPA131U draws ±1.5 mA to ±2 mA of quiescent current per amplifier at 25°C, depending on supply voltage and process variation. This value remains stable across the –40°C to +85°C operating range, enabling predictable power budgeting in thermally constrained industrial and portable instrumentation designs.
Can the OPA131U drive ADC inputs directly?
Yes, the OPA131U can directly drive most SAR and delta-sigma ADC inputs due to its excellent capacitive load drive capability (stable with ≥300 pF) and fast 0.1% settling time of 1.5 μs. Its rail-to-rail output swing and low THD+N (0.0008%) preserve signal integrity without requiring additional buffer stages in precision DAQ systems.
Is the OPA131U RoHS-compliant and lead-free?
Yes, the OPA131UJ/2K5.B variant (matching the exact ordering row provided) is RoHS-compliant with NiPdAu lead finish and MSL Level-3 moisture sensitivity rating. It meets JEDEC J-STD-020 reflow profile requirements (peak 260°C) and is qualified for lead-free assembly processes used in modern industrial electronics manufacturing.
OPA131U 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
OPA131U FAQ
1.How can I place an order for OPA131U through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA131U 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 reliable?
The price and inventory of OPA131U are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA131U is usually 5 days.
3.What payment methods are accepted for OPA131U?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA131U transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA131U?
OPA131U orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA131U 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?
For technical support, including OPA131U datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA131U requirements.
6.How does Aetrix verify that OPA131U is sourced from the original manufacturer or authorized distributors?
All OPA131U 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 meets industry standards.
7.What is the process for return or replacement of OPA131U?
All OPA131U units undergo pre-shipment inspection (PSI). If there is an issue with OPA131U, 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 part is unused and in its original packaging.
Return procedure for OPA131U:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
OPA131U Tags
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