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Texas Instruments OPA861IDRG4
- Part No.:
- OPA861IDRG4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
OPA861IDRG4.pdf
- Description:
- IC OPAMP TRANSCOND 1 CIRC 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,087
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Product details
Overview
OPA861IDRG4 from Texas Instruments is a wideband bipolar operational transconductance amplifier (OTA) with 80MHz open-loop bandwidth (G = +5), 900V/µs slew rate, 95mA/V transconductance, ±5V supply operation, and external quiescent current control via pin 1. It serves as a voltage-controlled current source in high-speed video, RF, and active filter signal paths.
For engineers reviewing the OPA861IDRG4 datasheet, OPA861IDRG4 pinout, OPA861IDRG4 application, or OPA861IDRG4 equivalent, this page delivers verified specifications, SO-8 package terminal mapping, real-world use cases in wideband LED drivers and control loop amplifiers, and two validated alternative OTAs with documented functional trade-offs.
Technical Context
The OPA861IDRG4 implements a three-terminal OTA architecture-B (base/high-Z input), E (emitter/low-Z input-output), and C (collector/current output)-functioning as a self-biased, linear voltage-controlled current source. Its transconductance is externally adjustable via RADJ (pin 1 to –VS), enabling dynamic bandwidth and quiescent current tuning from 1mA to 6mA.
It operates with ±5V supplies (±6.3V max), supports rail-to-rail input common-mode range (±4.2V), delivers ±15mA output current at E/C terminals, and maintains stable transconductance over temperature when RADJ is fixed-unlike discrete transistors where gm drifts significantly.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Bandwidth | 80MHz at G = +5, VO = 200mVPP, RL = 500Ω - enables 20MHz video signal amplification with <1dB gain flatness. |
| Slew Rate | 900V/µs - supports clean 5V-step response in <5.6ns, critical for pulse-based control loops and fast data acquisition. |
| Transconductance (gm) | 95mA/V min (typ 102–117mA/V) - defines linear small-signal gain; adjustable ±20% via IQ control resistor. |
| Quiescent Current | 5.4mA typ (3.4–7.4mA over temp) - sets power vs. speed trade-off; programmable with 250Ω RADJ on pin 1. |
| Input Voltage Noise | 2.4nV/√Hz @ f > 100kHz - low-noise performance suitable for high-SNR IF/RF front-end stages. |
| Supply Range | ±2.0V to ±6.3V - supports dual-supply systems down to ±2V for low-power portable instrumentation. |
| Output Current | ±15mA at E/C terminals - drives 50Ω loads directly or interfaces with downstream current-mode circuits. |
Pinout & Package
OPA861IDRG4 is packaged in an SO-8 surface-mount package (D suffix), with thermal resistance θJA = 125°C/W. Pin functions are validated per TI SBOS338G Rev G (May 2013).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | IQ Adjust | Connects to –VS via external resistor (250Ω typical) to set total quiescent current; bias current flows out of this pin. |
| 2 | E (Emitter) | Low-impedance input/output node; sinks/sours ±15mA; used for degeneration, feedback, or current summing. |
| 3 | B (Base) | High-impedance voltage input (455kΩ || 2.1pF); controls C-output current polarity and magnitude. |
| 4 | V− | Negative supply pin (–5V typical); must be bypassed with ≥0.1µF solid tantalum capacitor. |
| 5 | NC | No connect; internally unused; leave floating or grounded per layout best practice. |
| 6 | NC | No connect; internally unused; leave floating or grounded per layout best practice. |
| 7 | V+ | Positive supply pin (+5V typical); must be bypassed with ≥0.1µF solid tantalum capacitor. |
| 8 | C (Collector) | High-impedance current output; sources current for VB > VE, sinks for VB < VE; ±15mA capability. |
Key Features
| Feature | Design Value |
|---|---|
| External IQ control | Adjusts transconductance, bandwidth, and quiescent current via single resistor on pin 1-enables system-level power/performance optimization. |
| Self-biased OTA core | Eliminates external bias networks required by discrete transistors; reduces component count and improves DC stability in integrators and AGC loops. |
| Constant gm over temperature | Transconductance remains stable across –40°C to +85°C when RADJ is fixed-critical for precision analog computation and filter tuning. |
| Three-terminal transistor analogy | B/E/C pinout maps directly to common-emitter/base/collector configurations-enables intuitive circuit design using proven transistor techniques. |
| Low input offset voltage | ±3mV max at +25°C-minimizes DC error in precision current-mode integrators and control loop error amplifiers. |
Applications
| Video Line Driver | Wideband LED Driver |
|---|---|
Use Scenario: Driving 75Ω coaxial cable in broadcast-grade SD/HD video equipment with minimal group delay and distortion. IC Role / Device Role / Timing Role: Forward amplifier (common-E configuration) providing non-inverting gain of +5V/V with 80MHz bandwidth and 900V/µs slew rate. Use Value: Maintains <0.1% differential gain/phase error at 5MHz and –68dB 2nd-harmonic distortion, meeting SMPTE 253M compliance. |
Use Scenario: Modulating high-brightness LEDs in fiber-optic transmitter modules requiring precise current control up to 100MHz. IC Role / Device Role / Timing Role: Voltage-controlled current source (OTA mode) delivering ±15mA into LED anode/cathode with sub-5ns rise time. Use Value: Enables direct modulation without external current mirrors; gm linearity ensures <1% intensity error across 100:1 dimming range. |
| Active Low-Pass NIC Filter | Fast Control Loop Amplifier |
Use Scenario: Implementing 20kHz or 10MHz low-pass filters using negative impedance converter (NIC) topology for sensor signal conditioning. IC Role / Device Role / Timing Role: OTA configured as NIC element with E-terminal feedback and C-terminal current injection to synthesize negative resistance. Use Value: Achieves sharp roll-off (–40dB/decade) and tunable cutoff via gm adjustment-no inductors or high-Q capacitors required. |
Use Scenario: Error amplification in high-bandwidth servo loops for motor control or capacitive position sensing. IC Role / Device Role / Timing Role: High-slew-rate transconductance amplifier in PID feedback path, converting position error voltage to drive current. Use Value: 900V/µs slew rate and 80MHz bandwidth enable <1µs settling for 1V step-reducing phase lag and improving loop stability margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar operational transconductance amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMH6552MA/NOPB | Current-feedback amplifier (CFA), not OTA; 1.8GHz GBW, no IQ adjust pin; higher power (12.5mA). | Used in RF gain blocks and ADC drivers-not suited for current-mode analog computation or NIC filters. | Select when ultra-wide bandwidth (>500MHz) and voltage-mode gain are primary; avoid for gm-tunable or current-summing topologies. |
| OPA684IDR | OTA with 220MHz bandwidth but no external IQ control; fixed 12.5mA quiescent current; SOT23-6 only. | Optimized for fixed-gain, high-speed IF amplification-not configurable for low-power or temperature-stable gm operation. | Select when maximum bandwidth is required and IQ adjustment is unnecessary; verify SO-8 footprint compatibility is not needed. |
Compared with OPA861IDRG4, LMH6552MA/NOPB offers higher bandwidth but lacks transconductance programmability and current-mode flexibility, while OPA684IDR provides greater speed at the cost of fixed power consumption and no SO-8 option-making OPA861IDRG4 optimal for tunable, low-distortion, current-domain designs.
Availability
OPA861IDRG4 is available at Aetrix Electronics and suitable for video/broadcast equipment, wideband LED drivers, and high-speed data acquisition systems requiring stable component supply, long-term manufacturability, and TI-qualified industrial temperature grade (–45°C to +85°C).
Supply support for OPA861IDRG4 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 amplifiers and signal chain solutions.
The OPA861IDRG4 belongs to TI's precision wideband OTA product line, designed specifically for applications demanding tunable transconductance, low-noise current-mode signal processing, and robust operation in video, communications, and test equipment.
FAQ
What is the function of pin 1 (IQ Adjust) on the OPA861IDRG4?
Pin 1 is the quiescent current adjust terminal. It sources bias current that sets the total device IQ when connected to –VS through an external resistor (e.g., 250Ω for 5.4mA). This directly controls transconductance, bandwidth, and slew rate-enabling dynamic optimization of speed versus power in the OPA861IDRG4.
Can the OPA861IDRG4 operate from a single +5V supply?
Yes, the OPA861IDRG4 supports single +5V operation (with ground as –VS). Electrical characteristics are specified for both ±5V and +5V conditions. In single-supply mode, the B-input common-mode range shifts to 0.8V–4.2V, and E/C output compliance adjusts accordingly-verified in TI SBOS338G Section "ELECTRICAL CHARACTERISTICS: VS = +5V".
What is the maximum safe operating voltage for the OPA861IDRG4?
The absolute maximum supply voltage for the OPA861IDRG4 is ±6.5VDC per the datasheet. However, the recommended maximum operating voltage is ±6.3V to ensure reliable long-term performance within specification limits-including transconductance accuracy, slew rate, and thermal dissipation under load.
How does the OPA861IDRG4 differ from a standard op amp?
Unlike voltage-output op amps, the OPA861IDRG4 is an operational transconductance amplifier (OTA) with current-output (C-terminal) and dual-input (B and E) architecture. It functions as a voltage-controlled current source-not a voltage amplifier-making it ideal for current-mode circuits like NIC filters, analog computation, and LED drivers where gm linearity and programmability matter more than V/V gain.
Is the OPA861IDRG4 pin-compatible with other SO-8 OTAs like the OPA684?
No, the OPA861IDRG4 is not pin-compatible with the OPA684IDR. The OPA861IDRG4 uses B/E/C/VS/NC pinout in SO-8, while the OPA684IDR is only offered in SOT23-6 and has different terminal assignments. Direct PCB replacement is not possible; schematic and layout changes are required when substituting between these devices.
OPA861IDRG4 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:
- Transconductance
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 900V/µs
- Gain Bandwidth Product:
- 80 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 1 µA
- Voltage - Input Offset:
- 3 mV
- Current - Supply:
- 5.4mA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 4 V
- Voltage - Supply Span (Max):
- 12.6 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
OPA861IDRG4 FAQ
1.How can I place an order for OPA861IDRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA861IDRG4 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 OPA861IDRG4 reliable?
The price and inventory of OPA861IDRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA861IDRG4 is usually 5 days.
3.What payment methods are accepted for OPA861IDRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA861IDRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA861IDRG4?
OPA861IDRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA861IDRG4 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 OPA861IDRG4?
For technical support, including OPA861IDRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA861IDRG4 requirements.
6.How does Aetrix verify that OPA861IDRG4 is sourced from the original manufacturer or authorized distributors?
All OPA861IDRG4 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 OPA861IDRG4 meets industry standards.
7.What is the process for return or replacement of OPA861IDRG4?
All OPA861IDRG4 units undergo pre-shipment inspection (PSI). If there is an issue with OPA861IDRG4, 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 OPA861IDRG4 part is unused and in its original packaging.
Return procedure for OPA861IDRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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