Texas Instruments OPA4684IPWRG4

Overview

OPA4684IPWRG4 from Texas Instruments is a quad, low-power, current-feedback operational amplifier designed for wideband analog signal conditioning in broadcast video, ADC drivers, 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 OPA4684IPWRG4 datasheet, OPA4684IPWRG4 pinout, OPA4684IPWRG4 application, or OPA4684IPWRG4 equivalent, key selection considerations include its CFBPLUS architecture enabling stable bandwidth vs. gain, minimal output headroom (1.2V), low 1.7mA/ch quiescent current, and TSSOP-14 package suitability for multichannel high-density layouts.

Technical Context

The OPA4684IPWRG4 implements a patented CFBPLUS architecture featuring an internally closed-loop input buffer stage that linearizes inverting-input impedance-enabling near-constant bandwidth up to G = +10 and improved harmonic distortion over conventional low-power CFB amplifiers. Its transimpedance gain is 355kΩ (min) with 0.006Ω closed-loop output impedance at 100kHz.

This architecture decouples gain-setting resistor (RG) selection from bandwidth degradation, allowing peaking elements and multichannel summing circuits without sacrificing frequency response. Input common-mode range extends to ±3.6V on ±5V supplies, and output swing reaches ±3.8V into 1kΩ at +85°C.

Key Specifications

Pinout & Package

TSSOP-14 package (PW suffix), 5.0mm × 4.4mm body, 0.65mm pitch, exposed thermal pad (not electrically connected). Pin 1 marked by dot; pin numbering follows standard TSSOP convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA2684IDR and OPA3684IPW, the OPA4684IPWRG4 provides integrated quad-channel matching in a single TSSOP-14 package-reducing layout complexity, inter-channel skew, and total solution size while maintaining identical per-channel AC performance and power efficiency.

Availability

OPA4684IPWRG4 is available at Aetrix Electronics and suitable for broadcast video infrastructure, medical imaging front-ends, test equipment signal chains, and industrial ADC interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for OPA4684IPWRG4 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 amp design and manufacturing.

The OPA4684IPWRG4 belongs to TI's CFBPLUS current-feedback op amp product line, engineered specifically for low-power, wideband analog signal conditioning in broadcast, instrumentation, and communications systems where gain-stable bandwidth and low distortion are critical.

FAQ

What supply voltage ranges does the OPA4684IPWRG4 support?

The OPA4684IPWRG4 supports dual-supply operation from ±2.5V to ±6.0V and single-supply operation from +2.8V to +12V. At ±5V, it delivers full specified performance including 170MHz bandwidth and 120mA output current. The device maintains stable operation across this range due to internal supply-independent biasing, with quiescent current varying only ±0.25mA per channel from ±2.5V to ±6V.

How does the CFBPLUS architecture improve bandwidth stability versus traditional CFB op amps?

The OPA4684IPWRG4's CFBPLUS architecture uses an internally closed-loop input buffer to linearize the inverting-input impedance to ~5Ω, decoupling bandwidth from gain-setting resistor variations. This enables bandwidth retention up to G = +10 (120MHz) with <3dB variation-unlike earlier low-power CFB amplifiers where bandwidth dropped sharply above G = +2. The result is predictable frequency response in equalizing filters and multichannel summing circuits.

Can the OPA4684IPWRG4 drive 50Ω transmission lines directly?

Yes-the OPA4684IPWRG4 can source/sink >±3V into 50Ω loads while maintaining <–70dBc harmonic distortion at 5MHz, meeting SMPTE 259M video line driver requirements. For optimal performance, use a series 50Ω resistor at the output pin to match the trace impedance and prevent reflections; the 0.006Ω closed-loop output impedance ensures minimal signal loss across the termination.

What is the maximum output voltage swing for OPA4684IPWRG4 on ±5V supplies?

On ±5V supplies, the OPA4684IPWRG4 delivers a minimum ±3.8V output swing into 1kΩ at +85°C, and ±4.1V at +25°C. With 100Ω load, it sustains >±3V swing while preserving <–70dBc distortion-enabling direct interface to doubly-terminated 50Ω video cables. Input common-mode range extends to ±3.6V, allowing full utilization of the output swing without clipping.

Is thermal management required for continuous operation of OPA4684IPWRG4 in TSSOP-14 package?

Yes-thermal management is essential. The TSSOP-14 package (PW) has θJA = 110°C/W. At 6.8mA total supply current and worst-case 120mA output sourcing, power dissipation can reach ~150mW. To maintain junction temperature below 150°C in +85°C ambient, ensure the exposed thermal pad is soldered to ≥1cm² copper pour with ≥4 thermal vias to inner ground planes. Without proper thermal relief, derating of output current and bandwidth may occur above +70°C ambient.