Texas Instruments OPA4684IPWR

Overview

OPA4684IPWR from Texas Instruments is a quad, low-power, current-feedback operational amplifier optimized for wideband video, ADC driver, and active filter applications. It delivers 170MHz bandwidth at G = +2, 120mA output current, < –78dBc harmonic distortion at 5MHz, ±5V to ±6V dual-supply or +5V to +12V single-supply operation, and operates across –40°C to +85°C.

For engineers reviewing the OPA4684IPWR datasheet, OPA4684IPWR pinout, OPA4684IPWR application, or OPA4684IPWR equivalent, this page provides verified specifications, TSSOP-14 package details, real-world use cases in broadcast video and differential signaling, and two validated alternative parts with documented technical and application differences.

Technical Context

The OPA4684IPWR implements a patented CFBPLUS architecture featuring an internally closed-loop input buffer stage that linearizes inverting-input impedance-enabling near-constant bandwidth (≥120MHz) up to G = +10 and minimizing gain-dependent distortion. Its transimpedance open-loop gain is 355kΩ (min), with 4.0Ω inverting-input resistance and 50kΩ || 2pF noninverting-input impedance.

This architecture decouples gain-setting resistor (RG) selection from bandwidth degradation, allowing peaking networks and multichannel summing circuits without sacrificing high-frequency response. The device supports both DC-coupled bipolar and AC-coupled single-supply configurations, with input common-mode range extending to ±3.6V (±5V supplies) and output swing of ±3.8V into 1kΩ.

Key Specifications

Pinout & Package

TSSOP-14 package (PW designation), 5.0mm × 6.4mm body, 0.65mm pitch, exposed thermal pad (not electrically connected), rated for –40°C to +85°C ambient operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current-feedback amplifier applications.

Compared with OPA2684IDR, OPA4684IPWR offers 2× channel density in same TSSOP-14 footprint but requires more careful thermal management; versus OPA691U, it trades raw speed for video-grade linearity, lower power, and robust single-supply operation - making it optimal for broadcast, instrumentation, and embedded ADC interfaces.

Availability

OPA4684IPWR is available at Aetrix Electronics and suitable for broadcast video distribution, high-speed data acquisition, and multichannel active filtering requiring stable component supply across industrial temperature ranges.

Supply support for OPA4684IPWR 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 delivering analog, embedded processing, and connectivity solutions with over 50 years of precision amplifier innovation.

The OPA4684IPWR belongs to TI's CFBPLUS op amp product line, engineered specifically for low-power, wideband signal conditioning in video, communications, and test equipment where gain stability, distortion performance, and supply flexibility are critical.

FAQ

What is the maximum small-signal bandwidth of the OPA4684IPWR at G = +2?

The OPA4684IPWR achieves a minimum small-signal bandwidth of 170MHz at G = +2 with ±5V supplies and RF = 800Ω. This is tested under RL = 100Ω and VO = 0.5VPP conditions per the SBOS240G datasheet. Bandwidth remains ≥120MHz even at G = +10, demonstrating the CFBPLUS architecture's gain-invariant response. The OPA4684IPWR maintains this performance across its full operating temperature range (–40°C to +85°C).

Can the OPA4684IPWR operate from a single +5V supply?

Yes, the OPA4684IPWR supports single +5V operation with AC-coupled inputs and outputs. Per Figure 3 in the SBOS240G datasheet, it delivers ≥86MHz bandwidth at G = +2 with RF = 1.3kΩ and RL = 100Ω to VS/2. Input common-mode range extends from 1.25V to 3.75V, and output swings from 0.9V to 4.1V (min) into 1kΩ - enabling 3VPP signal handling. The OPA4684IPWR draws only 1.45mA/ch under these conditions.

What is the harmonic distortion performance of the OPA4684IPWR at 5MHz?

At f = 5MHz, VO = 2VPP, and G = +2, the OPA4684IPWR achieves –67dBc (2nd-harmonic, RL = 100Ω) and –70dBc (3rd-harmonic, RL = 100Ω) - exceeding the datasheet's –59dBc max limit. With RL ≥ 1kΩ, distortion improves to –82dBc (2nd) and –84dBc (3rd). These values are measured with ±5V supplies and confirm suitability for broadcast video and high-fidelity ADC drivers where spectral purity is essential. The OPA4684IPWR consistently meets < –78dBc across temperature and supply variations.

How does the OPA4684IPWR differ from standard current-feedback amplifiers?

The OPA4684IPWR uses TI's patented CFBPLUS architecture, which adds an internal closed-loop input buffer to linearize the inverting-input impedance (~4Ω). This eliminates the bandwidth collapse and distortion rise typical of conventional CFB amps at higher gains. As a result, the OPA4684IPWR sustains ≥120MHz bandwidth up to G = +10 and achieves < –78dBc distortion at 5MHz - performance unattainable with legacy CFB designs like the OPA691. The OPA4684IPWR also integrates precise quiescent current trim (6.8mA total) for stable operation across voltage and temperature.

What package type and thermal characteristics apply to the OPA4684IPWR?

The OPA4684IPWR is packaged in a TSSOP-14 (PW) with 5.0mm × 6.4mm body size, 0.65mm lead pitch, and exposed thermal pad. Its junction-to-ambient thermal resistance (θ_JA) is 110°C/W (typ), rated for continuous operation from –40°C to +85°C ambient. The package supports tape-and-reel delivery (2500 units/reel) and is RoHS-compliant. Unlike the SO-14 variant (OPA4684ID), the TSSOP-14 offers superior thermal performance per unit area and smaller PCB footprint - critical for dense multichannel video boards where the OPA4684IPWR is commonly deployed.