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Texas Instruments OPA681N/250
- Part No.:
- OPA681N/250
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- SOT-23-6
- Datasheet:
-
OPA681N/250.pdf
- Description:
- IC OPAMP CFB 280MHZ SGL SOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:3,813
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Product details
Overview
OPA681N/250 from Texas Instruments is a wideband current-feedback operational amplifier optimized for single-supply +5V operation, delivering 225MHz small-signal bandwidth (G = +2), 2100V/µs slew rate, ±4.0V output swing, and 150mA output current - enabling high-fidelity RGB line driving and ADC input buffering in portable instrumentation and broadband video systems.
For engineers reviewing the OPA681N/250 datasheet, OPA681N/250 pinout, OPA681N/250 application, or OPA681N/250 equivalent, key selection criteria include disable-enabled power gating (320µA shutdown current), low differential gain/phase error (0.001%/0.01°), 6mA quiescent supply current, and SOT23-6 package compatibility with space-constrained PCB layouts.
Technical Context
The OPA681N/250 employs a current-feedback architecture where bandwidth remains stable across gains (+1 to +10), unlike voltage-feedback op amps. Its transimpedance gain is 100kΩ (min) at ±5V, with inverting-input resistance of 42Ω (typ) and non-inverting input impedance of 100kΩ || 2pF.
It features a proprietary output stage minimizing crossover distortion and voltage headroom - enabling 1V–4V output swing on +5V supply with >100mA drive into 100Ω. The DIS pin provides <100ns disable time and 25ns enable time, placing output in high-Z state while reducing supply current to 320µA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Small-Signal Bandwidth | 225MHz at G = +2, +5V supply - supports >100MHz video and IF signal paths without gain-dependent bandwidth collapse. |
| Slew Rate | 2100V/µs at G = +2, ±5V - enables clean 5Vp-p transient response with <2ns rise/fall time for fast imaging and pulse applications. |
| Output Current | ±150mA min sourcing/sinking - drives 75Ω video lines, 100Ω ADC inputs, or parallel loads without external buffers. |
| Differential Gain/Phase | 0.001% / 0.01° at NTSC, RL = 150Ω - preserves color fidelity in composite/S-video buffer stages. |
| Disable Current | 320µA max at VDIS = 0 - reduces system standby power by >94% vs active mode (6mA), critical for battery-powered instruments. |
| Input Voltage Noise | 2.2nV/√Hz above 1MHz - maintains SNR integrity in wideband IF amplifiers and high-speed data acquisition front ends. |
| Supply Range | ±5V (bipolar) or +5V single supply - operates from 12V max single supply, supporting legacy and modern rail-constrained designs. |
Pinout & Package
SOT23-6 package (θJA = 150°C/W), 6-pin surface-mount with exposed pad for thermal enhancement. Pin 1 marked by dot; top-view orientation per TI drawing 332.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Amplifier Output | High-current, low-impedance output node capable of ±150mA drive; requires series resistor for 75Ω video termination. |
| 2 (–VS) | Negative Supply Rail | Connect to ground in single-supply +5V operation; must be decoupled with 0.1µF ceramic capacitor near pin. |
| 3 (IN–) | Inverting Input | Current-summing node with 42Ω typical input resistance; sets feedback gain and stability via RF/RI ratio. |
| 4 (IN+) | Non-Inverting Input | Voltage-sensing node with 100kΩ || 2pF impedance; biasing required for DC-coupled single-supply use. |
| 5 (DIS) | Disable Control (Active-Low) | Pull ≤1.5V to enter low-power state; open or ≥3.3V for normal operation; 100µA max input bias current. |
| 6 (+VS) | Positive Supply Rail | Accepts +5V (single) or ±5V (dual); internal biasing is supply-independent, enabling robust performance across rail configurations. |
Key Features
| Feature | Design Value |
|---|---|
| Wideband +5V Operation | 225MHz bandwidth at G = +2 on single +5V supply - eliminates need for dual-rail supplies in portable video/ADC systems. |
| High Output Current | 150mA guaranteed sourcing/sinking - directly drives 75Ω coaxial cables, 100Ω ADC inputs, or multiple parallel loads. |
| Low Disable Current | 320µA shutdown current - enables dynamic power gating in multi-channel video MUX or battery-operated test equipment. |
| Ultra-Low dG/dφ | 0.001% differential gain / 0.01° differential phase error - meets broadcast-grade video linearity requirements (NTSC/PAL). |
| Fast Enable/Disable | 25ns enable / 100ns disable timing - supports sub-microsecond channel switching in wired-OR video multiplexers. |
Applications
| RGB Line Driver | Single-Supply ADC Driver |
|---|---|
|
Use Scenario: Driving three parallel 75Ω coaxial cables carrying red, green, and blue analog video signals from graphics processor to display interface. IC Role / Device Role / Timing Role: High-speed, low-distortion unity-gain buffer with matched propagation delay across channels. Use Value: Maintains 0.001% differential gain and 0.01° phase accuracy across full 0–100MHz video bandwidth, preserving color fidelity without external calibration. |
Use Scenario: Conditioning analog input to a 10-bit, 60MSPS ADC (e.g., ADS823) in portable spectrum analyzer front end. IC Role / Device Role / Timing Role: Single-supply +5V driver providing 2Vp-p signal swing with >180MHz bandwidth and >58dBc SFDR at 20MHz. Use Value: Enables DC-coupled, rail-efficient signal chain with no level-shifting circuitry, reducing component count and layout area. |
| Video Multiplexer | IF Amplifier |
|
Use Scenario: Selecting between two SD/HD video sources using "wired-OR" topology with make-before-break switching during vertical blanking interval. IC Role / Device Role / Timing Role: Channel-selectable buffer with high-Z output disable and <20mV switching glitch under matched-load conditions. Use Value: Eliminates mechanical relays or analog switches; supports seamless source transitions with no visible sync disturbance or ghosting. |
Use Scenario: Amplifying 10–70MHz IF signals in handheld RF receiver with duty-cycled operation to extend battery life. IC Role / Device Role / Timing Role: Low-noise, high-linearity gain block with 2.2nV/√Hz input noise and –72dBc 3rd-harmonic distortion at 5MHz. Use Value: Delivers >65dBc IP3 at 15dBm output compression while consuming only 6mA - outperforming discrete transistor IF stages in size and power. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed current-feedback amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA681U | SO-8 package (θJA = 125°C/W); identical electrical specs; no lead-free option in N variant. | Better thermal dissipation for continuous high-output-power operation; larger footprint unsuitable for ultra-dense layouts. | Select OPA681U when board space allows and thermal margin is prioritized over miniaturization. |
| OPA2681 | Dual-channel version in SO-8 or MSOP-8; shared supply pins; 6mA per channel quiescent current. | Reduces component count in multi-channel video or I/Q signal paths but increases inter-channel crosstalk risk above 50MHz. | Choose OPA2681 only when dual-channel synchronization is required and layout isolation can suppress >40dB crosstalk at target frequency. |
Compared with OPA681U and OPA2681, the OPA681N/250 offers the smallest footprint (SOT23-6), lowest thermal resistance penalty for space-constrained portable designs, and tape-and-reel convenience for automated assembly - making it optimal for single-channel, battery-sensitive applications like handheld test gear and embedded video interfaces.
Availability
OPA681N/250 is available at Aetrix Electronics and suitable for RGB line driving, single-supply ADC buffering, and portable instrument design requiring stable component supply, consistent parametric performance across temperature, and long-term lifecycle support.
Supply support for OPA681N/250 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, embedded processing, and high-performance signal-chain solutions with decades of op amp innovation.
The OPA681N/250 belongs to TI's precision high-speed amplifier portfolio, engineered specifically for demanding single-supply video, imaging, and data acquisition systems where bandwidth, linearity, and power efficiency must coexist.
FAQ
What is the maximum operating voltage for the OPA681N/250?
The OPA681N/250 supports a maximum operating voltage range of ±6V for dual-supply use and up to +12V for single-supply operation. Absolute maximum ratings specify ±6.5V on power rails; exceeding these risks permanent damage. For reliable operation at +5V single supply, ensure input common-mode voltage stays within 1.5V to 3.5V and output swing remains between 1.0V and 4.0V under load.
Does the OPA681N/250 require external compensation for stability?
No, the OPA681N/250 is unity-gain stable with 280MHz bandwidth at G = +1 and does not require external compensation capacitors. Stability is maintained across gains from +1 to +10 when using recommended feedback resistors (e.g., 499Ω at +5V, 402Ω at ±5V). Layout best practices - including short traces, local 0.1µF bypass caps at each supply pin, and proper grounding - are sufficient for robust high-frequency operation.
How does the disable function affect output behavior in the OPA681N/250?
When the DIS pin is pulled low (<1.5V), the OPA681N/250 enters power-down mode: supply current drops to ≤320µA and the output transitions to high-impedance state within 100ns. During disable, output capacitance is 4pF (typ), and off-isolation exceeds 65dB at 5MHz. Turn-on/off glitches are limited to ±50mV and ±20mV respectively - critical for clean video MUX transitions.
Can the OPA681N/250 drive a 75Ω video load directly?
Yes, the OPA681N/250 can drive a 75Ω load directly when configured with appropriate series output resistance (e.g., 82.5Ω) to match cable impedance and prevent reflections. At G = +1, it delivers >150MHz bandwidth and maintains 0.001% differential gain/0.01° phase error - meeting SMPTE 253M and ITU-R BT.601 video standards without additional equalization.
What is the thermal resistance (θJA) of the OPA681N/250 package?
As a SOT23-6 device, the OPA681N/250 has a junction-to-ambient thermal resistance (θJA) of 150°C/W under standard JEDEC test conditions. This value assumes minimal copper area; adding a 10mm² thermal pad connected to internal ground plane reduces effective θJA by ~30–40°C/W. For continuous 150mA output into 75Ω at +5V, junction temperature rise remains within safe limits if ambient stays below +70°C.
OPA681N/250 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SpeedPlus™
- Package/Case:
- SOT-23-6
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Amplifier Type:
- Current Feedback
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 2100V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 280 MHz
- Current - Input Bias:
- 30 µA
- Voltage - Input Offset:
- 1.3 mV
- Current - Supply:
- 6mA
- Current - Output / Channel:
- 190 mA
- Voltage - Supply Span (Min):
- 5 V
- Voltage - Supply Span (Max):
- 12 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-6
OPA681N/250 FAQ
1.How can I place an order for OPA681N/250 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA681N/250 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 OPA681N/250 reliable?
The price and inventory of OPA681N/250 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA681N/250 is usually 5 days.
3.What payment methods are accepted for OPA681N/250?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA681N/250 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA681N/250?
OPA681N/250 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA681N/250 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 OPA681N/250?
For technical support, including OPA681N/250 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA681N/250 requirements.
6.How does Aetrix verify that OPA681N/250 is sourced from the original manufacturer or authorized distributors?
All OPA681N/250 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 OPA681N/250 meets industry standards.
7.What is the process for return or replacement of OPA681N/250?
All OPA681N/250 units undergo pre-shipment inspection (PSI). If there is an issue with OPA681N/250, 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 OPA681N/250 part is unused and in its original packaging.
Return procedure for OPA681N/250:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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