Texas Instruments THS4221D

Overview

THS4221D from Texas Instruments is a single-channel, rail-to-rail output, high-speed voltage-feedback operational amplifier optimized for low-distortion signal conditioning in data converter interfaces and video systems. It delivers 230 MHz small-signal bandwidth (G = 1), 975 V/µs slew rate, −90 dBc HD2 and −100 dBc HD3 at 5 MHz (RL = 499 Ω), and ±4.8 V output swing into 2 kΩ - enabling high-fidelity analog front-end design for ADC drivers and composite video amplification.

For engineers reviewing the THS4221D datasheet, THS4221D pinout, THS4221D application, or THS4221D equivalent, key selection criteria include its rail-to-rail output capability under ±5 V or single 5 V supply, thermal performance in SOIC-8 package, distortion-limited full-power bandwidth of 65 MHz, and compatibility with 150 Ω/75 Ω video loads requiring <0.007% differential gain error.

Technical Context

The THS4221D employs a voltage-feedback architecture with a fully differential input stage and Class-AB rail-to-rail output stage, supporting stable unity-gain operation without external compensation. Its internal biasing enables operation from ±1.35 V to ±7.5 V dual supplies or 2.7 V to 15 V single supply, with quiescent current tightly regulated at 14 mA per channel at ±5 V.

Unlike power-down variants (e.g., THS4225D), the THS4221D lacks a PD pin and reference input - it is a fixed-function, always-on amplifier. Its AC performance is characterized using 499 Ω loads and specified across −40°C to +85°C, with harmonic distortion measured at VO = 2 VPP and f = 5 MHz.

Key Specifications

Pinout & Package

The THS4221D is housed in an 8-pin SOIC (D) package with standard JEDEC MS-012AC footprint, 1.27 mm pitch, and exposed pad not present - thermal dissipation relies on PCB copper area per ΘJA = 97.5°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed op-amp applications.

Compared with OPA354AIDBVR and THS4271DR, the THS4221D uniquely balances 230 MHz bandwidth, −100 dBc HD3, and 14 mA quiescent current - making it optimal for cost-sensitive, medium-speed data acquisition and broadcast video where distortion and power are co-constrained.

Availability

THS4221D is available at Aetrix Electronics and suitable for high-speed ADC driver, composite video buffering, active filtering, low-voltage sensor signal conditioning, and broadcast-grade analog front-end designs requiring stable component supply and long-term manufacturability.

Supply support for THS4221D 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 power management ICs, with decades of expertise in high-performance op-amp design and manufacturing.

The THS4221D belongs to TI's THS422x family of rail-to-rail output, low-distortion, high-speed op-amps engineered specifically for data converter interface, video signal routing, and wideband analog signal conditioning in instrumentation and communications systems.

FAQ

What is the maximum supply voltage rating for the THS4221D?

The THS4221D has an absolute maximum supply voltage rating of ±8.25 V (dual supply) or 16.5 V (single supply), but its recommended operating range is ±1.35 V to ±7.5 V dual or 2.7 V to 15 V single. Operation beyond ±7.5 V or 15 V risks permanent damage and is outside guaranteed specifications. The THS4221D datasheet specifies full performance at ±5 V and 5 V supplies.

Does the THS4221D support single-supply operation with rail-to-rail input?

No - the THS4221D features rail-to-rail *output* only. Its input common-mode voltage range is VS− + 1.1 V to VS+ − 1.1 V (e.g., 1.1 V to 3.9 V on 5 V supply), excluding the rails. For true rail-to-rail input, consider alternatives like OPA837 or THP210. The THS4221D requires external biasing (e.g., mid-supply reference) for single-supply AC-coupled applications.

What is the thermal resistance (θJA) of the THS4221D in SOIC-8 package?

The THS4221D in SOIC-8 (D) package has a junction-to-ambient thermal resistance (θJA) of 97.5°C/W under JEDEC High-K test board conditions. This value assumes two 1-in² copper planes on inner layers. Real-world PCB layout with enhanced copper pour can reduce θJA to ~70°C/W, allowing continuous operation at up to 1.02 W power dissipation at TA ≤ 25°C before reaching the 125°C junction limit.

Can the THS4221D drive a 75 Ω video load directly?

Yes - the THS4221D delivers 100 mA output current and maintains 0.007% differential gain into 150 Ω loads (standard for PAL/NTSC). When driving 75 Ω, use a series 75 Ω resistor at the output to match source impedance and prevent reflections; the THS4221D sustains full rail-to-rail swing and <0.01% gain error under this condition. Verified in THS4221D datasheet Figure 16 and video performance tables.

Is the THS4221D pin-compatible with the THS4225D?

No - the THS4221D (no power-down) and THS4225D (with PD and REF pins) have different pinouts. THS4221D uses Pins 5 and 8 as NC; THS4225D assigns Pin 5 to PD and Pin 1 to REF. Substituting THS4221D for THS4225D disables power-down functionality and may cause incorrect biasing if REF is driven. Always verify pin mapping against SLOS399G Rev. January 2004, pages 9–10.