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Texas Instruments OPA656N/250G4
- Part No.:
- OPA656N/250G4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- SC-74A, SOT-753
- Datasheet:
-
OPA656N/250G4.pdf
- Description:
- IC OPAMP VFB 1 CIRCUIT SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,342
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Product details
Overview
OPA656N/250G4 from Texas Instruments is a unity-gain stable, FET-input voltage-feedback operational amplifier optimized for transimpedance and high-speed data acquisition front-ends. It delivers 550MHz unity-gain bandwidth, 6nV/√Hz input voltage noise, 2pA input bias current, and ±600μV max input offset voltage across –40°C to +85°C - enabling precision optical signal conditioning in photodiode-based OTDR and oscilloscope front-ends.
For engineers reviewing the OPA656N/250G4 datasheet, OPA656N/250G4 pinout, OPA656N/250G4 application, or OPA656N/250G4 equivalent, key selection criteria include its JFET-input low-noise performance, 230MHz gain-bandwidth product, large-signal bandwidth of 150MHz at 2VPP, ±6V maximum supply rating, and SOIC-8 package compatibility with high-impedance, wideband analog signal paths.
Technical Context
The OPA656N/250G4 employs a high-speed complementary bipolar process with a low-noise JFET input stage, achieving unity-gain stability without external compensation. Its open-loop gain exceeds 75dB with 230MHz gain-bandwidth product and 400V/µs slew rate, supporting stable operation at gains ≥1 V/V.
It features ultra-low input voltage noise (6nV/√Hz) and input bias current (2pA), making it suitable for transimpedance amplification where photodiode capacitance dominates noise shaping. The device operates from ±4V to ±6V supplies (8V–12V total), with specified performance over –40°C to +85°C industrial temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Unity-gain bandwidth | 550MHz - enables stable buffer operation up to UHF frequencies without peaking or oscillation |
| Gain-bandwidth product | 230MHz - defines maximum closed-loop bandwidth achievable at higher gains (e.g., 46MHz at G=5) |
| Input voltage noise | 6nV/√Hz - minimizes integrated noise in transimpedance applications with high RF values |
| Input bias current | 2pA - preserves DC accuracy in high-impedance sensor interfaces like photodiodes |
| Input offset voltage (max) | ±600μV - ensures sub-mV DC error in precision optical front-ends and test equipment |
| Large-signal bandwidth | 150MHz at 2VPP - supports fast pulse acquisition in DAQ and active probe designs |
| Supply voltage range | ±4V to ±6V (8V–12V total) - compatible with standard dual-rail lab and instrumentation power rails |
Pinout & Package
OPA656N/250G4 is packaged in an 8-pin SOIC (D package), 4.9mm × 6mm body size, with exposed pad not present. Pin functions are validated per TI SBOS196I Rev. F (Feb. 2024).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1, 5, 8 | NC | No internal connection - must be left unconnected or grounded only if required by layout EMI mitigation |
| 2 | VIN− | Inverting input - connects to feedback network in transimpedance or inverting configurations |
| 3 | VIN+ | Noninverting input - referenced to ground or bias voltage; high-impedance node for sensor inputs |
| 4 | −VS | Negative power supply - requires local 0.1μF + 6.8μF decoupling per TI layout guidelines |
| 6 | VOUT | Amplifier output - drives 100Ω loads directly; closed-loop output impedance <10mΩ below 100kHz |
| 7 | +VS | Positive power supply - symmetric dual-supply operation required for full dynamic range |
Key Features
| Feature | Design Value |
|---|---|
| Unity-gain stable architecture | Eliminates need for external compensation components in buffer or gain=1 transimpedance designs |
| JFET input stage | Enables 2pA input bias current and >1TΩ common-mode input impedance for photodiode leakage immunity |
| Low distortion at 5MHz | HD2 = –75dBc and HD3 = –90dBc into 200Ω - preserves signal fidelity in oscilloscope and DAQ front-ends |
| High PSRR | +PSRR = 85dB and –PSRR = 80dB - rejects supply ripple in sensitive optical receiver stages |
| Industrial temperature range | Specified from –40°C to +85°C - supports deployment in medical analyzers and field-deployable test gear |
Applications
| Optical Time-Domain Reflectometry (OTDR) | Oscilloscope Front-End Amplifier |
|---|---|
Use Scenario: Detecting weak backscattered light pulses from fiber-optic cables over distances up to 100km. IC Role / Device Role / Timing Role: Transimpedance amplifier converting photodiode current to voltage with minimal added noise and phase distortion. Use Value: 6nV/√Hz input voltage noise and 150MHz large-signal bandwidth enable sub-nanosecond pulse resolution and dynamic range >70dB. |
Use Scenario: Amplifying high-frequency analog signals before digitization in real-time digital storage oscilloscopes. IC Role / Device Role / Timing Role: Wideband gain block in the vertical signal path, maintaining flat frequency response and low group delay variation. Use Value: 550MHz unity-gain bandwidth and 400V/µs slew rate support accurate reproduction of 100MHz+ square waves with <1% overshoot. |
| Active Probe Signal Conditioning | Medical Laser Pulse Detection |
Use Scenario: Buffering and attenuating high-impedance DUT signals while preserving bandwidth and minimizing loading effects. IC Role / Device Role / Timing Role: Unity-gain follower with ultra-high input impedance (>10¹²Ω) and low output impedance (<1Ω). Use Value: 2pA input bias current prevents DC shift on high-Z nodes; 123°C/W junction-to-ambient thermal resistance allows compact probe PCB layouts. |
Use Scenario: Converting photocurrent from pulsed laser diode receivers in blood oxygen saturation (SpO₂) or flow cytometry systems. IC Role / Device Role / Timing Role: Low-noise, DC-coupled transimpedance amplifier for sub-microsecond optical pulse capture. Use Value: ±600μV max input offset voltage and ±12μV/°C drift ensure stable baseline over clinical operating temperatures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed, low-noise op-amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA814 | Higher GBW (250MHz), faster slew rate (750V/µs), lower voltage noise (5.3nV/√Hz), same 1-V/V minimum stable gain | Better suited for >200MHz small-signal applications but less optimized for transimpedance due to higher bias current (10pA) | Select OPA814 when prioritizing speed over ultra-low input current in non-photodiode applications |
| OPA659 | Higher GBW (350MHz), higher input voltage noise (8.9nV/√Hz), higher input bias current (10pA), same JFET input topology | Targeted at higher-frequency instrumentation where noise floor is less critical than bandwidth | Choose OPA659 only when 350MHz GBW is mandatory and 8.9nV/√Hz noise is acceptable |
Compared with OPA656N/250G4, OPA814 offers superior speed and noise but trades off input bias current; OPA659 extends bandwidth further but degrades noise and bias current specs - making OPA656N/250G4 the optimal balance for precision transimpedance and moderate-bandwidth DAQ front-ends.
Availability
OPA656N/250G4 is available at Aetrix Electronics and suitable for optical time-domain reflectometry (OTDR), oscilloscope front-end amplification, and active probe signal conditioning requiring stable component supply, long-lifecycle support, and traceable sourcing.
Supply support for OPA656N/250G4 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 high-performance op-amps and precision signal-chain solutions.
The OPA656N/250G4 belongs to TI's OPA high-speed precision op-amp family, designed specifically for wideband transimpedance amplification, optical test equipment, and high-fidelity data acquisition front-ends demanding low noise, low distortion, and unity-gain stability.
FAQ
What is the maximum supply voltage for OPA656N/250G4?
The OPA656N/250G4 has an absolute maximum supply voltage rating of ±6.5V, with recommended operation between ±4V and ±6V (8V–12V total). Exceeding ±6.5V risks permanent damage. The device is fully characterized at ±5V, and its quiescent current remains stable across the 8V–12V range per TI SBOS196I Section 6.3.
Is OPA656N/250G4 unity-gain stable?
Yes, OPA656N/250G4 is internally compensated for unity-gain stability. It achieves flat frequency response and no peaking at G = +1 V/V, with measured peaking ≤1dB at 550MHz. This eliminates the need for external compensation networks in buffer or transimpedance configurations, as confirmed in Section 6.5 and Figure 6-1 of the official datasheet.
What is the input bias current specification for OPA656N/250G4?
The input bias current for OPA656N/250G4 is ±2pA typical and ±20pA maximum at 25°C, rising to ±5000pA maximum over –40°C to +85°C. This ultra-low value stems from its JFET input stage and enables high-impedance photodiode interfacing without significant DC error - verified in Table 6-5 of SBOS196I.
Can OPA656N/250G4 be used in single-supply applications?
OPA656N/250G4 supports single-supply operation with appropriate input/output voltage headroom. Its input common-mode range extends to within 2.1V of the negative rail and 2.75V of the positive rail at 25°C, and output swings to within 1.3V of each rail under load. However, dual-supply (±5V) is recommended for optimal distortion and noise performance in precision applications.
What package type does OPA656N/250G4 use?
OPA656N/250G4 uses the 8-pin SOIC (D package) with dimensions 4.9mm × 6mm, as specified in TI's mechanical documentation (Section 11 of SBOS196I). This surface-mount package is RoHS-compliant, tape-and-reel deliverable, and compatible with standard automated assembly processes used in test equipment and medical instrumentation manufacturing.
OPA656N/250G4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Amplifier Type:
- Voltage Feedback
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 295V/µs
- Gain Bandwidth Product:
- 230 MHz
- -3db Bandwidth:
- 500 MHz
- Current - Input Bias:
- 2 pA
- Voltage - Input Offset:
- 250 µV
- Current - Supply:
- 14mA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 8 V
- Voltage - Supply Span (Max):
- 12 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
OPA656N/250G4 FAQ
1.How can I place an order for OPA656N/250G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA656N/250G4 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 OPA656N/250G4 reliable?
The price and inventory of OPA656N/250G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA656N/250G4 is usually 5 days.
3.What payment methods are accepted for OPA656N/250G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA656N/250G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA656N/250G4?
OPA656N/250G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA656N/250G4 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 OPA656N/250G4?
For technical support, including OPA656N/250G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA656N/250G4 requirements.
6.How does Aetrix verify that OPA656N/250G4 is sourced from the original manufacturer or authorized distributors?
All OPA656N/250G4 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 OPA656N/250G4 meets industry standards.
7.What is the process for return or replacement of OPA656N/250G4?
All OPA656N/250G4 units undergo pre-shipment inspection (PSI). If there is an issue with OPA656N/250G4, 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 OPA656N/250G4 part is unused and in its original packaging.
Return procedure for OPA656N/250G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
OPA656N/250G4 Tags
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