Texas Instruments THS3122IDR

Overview

THS3122IDR from Texas Instruments is a dual-channel, bipolar-input current feedback amplifier optimized for high-output-current, low-distortion video and instrumentation signal conditioning. It delivers 450 mA output drive, 128-MHz –3-dB bandwidth (RL = 50 Ω), 1550-V/µs slew rate (G = 2), and 2.2-nV/√Hz input voltage noise - enabling precise differential gain/phase performance (<0.01% / 0.011°) in 75-Ω serially terminated video distribution.

For engineers reviewing the THS3122IDR datasheet, THS3122IDR pinout, THS3122IDR application, or THS3122IDR equivalent, key selection criteria include its ±5 V to ±15 V dual-supply operation, SOIC-8 package with PowerPAD thermal enhancement, shutdown-incompatible design (vs. THS3125), and suitability for high-fidelity line drivers, piezo actuators, and motor control interface stages requiring wide output swing (±13.3 V into 50 Ω) and low harmonic distortion (–80 dBc at 1 MHz, 2 VPP).

Technical Context

The THS3122IDR implements a current feedback architecture with high-impedance noninverting inputs (1.5 MΩ) and low-impedance inverting inputs (15 Ω), enabling stable gain-setting via external feedback resistors without degrading bandwidth. Its transimpedance open-loop gain exceeds 1 MΩ, supporting fast settling (64 ns to 0.1%) and wide common-mode rejection (67 dB at ±15 V).

Unlike voltage-feedback amplifiers, it maintains constant bandwidth across gain configurations - e.g., 128 MHz at G = 2 and 160 MHz at G = 1 (RF = 750 Ω) - while delivering full-power bandwidth up to 64 MHz (20 VPP, ±15 V). Its bipolar input stage ensures low input bias current matching (3 µA max channel offset) and minimal drift (10 µV/°C).

Key Specifications

Pinout & Package

THS3122IDR is housed in an 8-pin SOIC (D) package with exposed PowerPAD thermal pad on the underside, requiring PCB copper pour connection for thermal management. The package measures 4.90 mm × 3.91 mm and supports JEDEC-standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with THS3122CDR, THS3122IDR provides guaranteed performance over –40°C to +85°C, essential for outdoor or factory-floor deployment; compared with THS3125IDR, it eliminates shutdown logic complexity and associated threshold-setting circuitry, simplifying layout and reducing BOM count in continuous-operation systems.

Availability

THS3122IDR is available at Aetrix Electronics and suitable for video distribution, instrumentation signal conditioning, and high-current line driving applications requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for THS3122IDR 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-speed amplifier design and manufacturing.

The THS312x product line was engineered specifically for demanding analog signal paths in professional video, test & measurement, and industrial motion control - prioritizing output drive, noise, and distortion performance over power efficiency.

FAQ

What is the maximum safe operating supply voltage for THS3122IDR?

The THS3122IDR has an absolute maximum supply voltage rating of ±16.5 V (33 V total across VCC+ and VCC−). However, the recommended operating range is ±5 V to ±15 V. Operating at ±15 V delivers full specified performance including 440-mA output drive and 128-MHz bandwidth; exceeding ±15 V risks accelerated parametric shift and reduced reliability, even if within absolute maximum limits.

Does THS3122IDR support shutdown functionality like THS3125IDR?

No, THS3122IDR does not include shutdown circuitry. Unlike THS3125IDR, which features SHUTDOWN and REF pins enabling 370-µA low-power mode, THS3122IDR operates continuously whenever powered. Its pinout omits SHUTDOWN and REF terminals entirely - confirmed by the SOIC-8 pin configuration table in the THS3122/THS3125 datasheet SLOS382E.

Can THS3122IDR drive a 50-Ω load with 20-VPP output swing?

No. At ±15 V supply, THS3122IDR delivers up to ±13.3 V (26.6 VPP) into 50 Ω, as specified in the Output Voltage Swing table. Attempting 20-VPP (±10 V) into 50 Ω is feasible, but 20-VPP would require ±10 V rails - insufficient for headroom. For true 20-VPP into 50 Ω, ±12 V minimum supply is needed; full 26.6-VPP requires ±15 V and proper thermal management via the PowerPAD.

What is the purpose of the PowerPAD on the THS3122IDR SOIC-8 package?

The exposed PowerPAD on the THS3122IDR's SOIC-8 package serves as a thermal conduction path from the die to the PCB. It must be soldered to a large copper pour connected to VCC− (or ground plane) to achieve the specified θJA of 95°C/W. Without this connection, junction temperature rises significantly - risking thermal shutdown or permanent damage during sustained 450-mA output operation.

How does THS3122IDR's current feedback architecture differ from standard op-amps in layout practice?

THS3122IDR's current feedback design demands strict layout discipline: the inverting input (1 IN−/2 IN−) must be kept extremely short and free of parasitic capacitance, as it acts as a low-impedance current summing node. Feedback resistors should be surface-mount, placed adjacent to the pin, and routed directly without vias. Ground planes must be solid beneath the device, and supply bypassing (0.1 µF ceramic + 4.7 µF tantalum) must be within 3 mm of each supply pin to prevent oscillation at >100 MHz.