Texas Instruments THS3125IDR

Overview

THS3125IDR from Texas Instruments is a dual-channel, bipolar-input, current-feedback amplifier optimized for low-noise, high-output-current 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 voltage noise - enabling precise differential gain/phase performance (<0.01% / 0.011°) in 75-Ω serially terminated video distribution systems.

For engineers reviewing the THS3125IDR datasheet, THS3125IDR pinout, THS3125IDR application, or THS3125IDR equivalent, key selection criteria include shutdown-enabled power management (370 µA quiescent current), dual-channel isolation, HTSSOP-14 PowerPAD™ thermal performance, and compatibility with ±5 V to ±15 V dual supplies for industrial line drivers and piezo actuator control.

Technical Context

The THS3125IDR implements a current-feedback architecture with separate high-impedance noninverting inputs (1 IN+, 2 IN+) and low-impedance inverting inputs (1 IN−, 2 IN−), enabling wide bandwidth independent of closed-loop gain. Its transimpedance gain stage drives a robust output stage capable of ±26-VPP swing into 50 Ω while maintaining –80 dBc THD at 1 MHz (2 VPP).

Shutdown functionality is controlled via the SHUTDOWN pin referenced to the REF pin, with enable/disable thresholds defined relative to REF (REF + 0.8 V enable, REF + 2 V disable). The REF pin accepts voltages from VCC− to VCC+ − 4 V, allowing flexible biasing for rail-to-rail shutdown control across supply ranges.

Key Specifications

Pinout & Package

THS3125IDR is housed in a thermally enhanced HTSSOP-14 (PWP) package with exposed PowerPAD™ on the underside, requiring PCB thermal pad connection for rated 3.3 W power dissipation (θJA = 37.5°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with THS3125IPWP, THS3125IDR offers identical performance in cut-tape form for flexibility in evaluation and low-volume builds; versus THS3095DR, THS3125IDR provides integrated dual-channel operation and 370-µA shutdown current-critical for portable or thermally constrained instrumentation designs.

Availability

THS3125IDR is available at Aetrix Electronics and suitable for video distribution, instrumentation signal conditioning, and industrial line drivers requiring stable component supply, long-term lifecycle assurance, and traceable sourcing from authorized channels.

Supply support for THS3125IDR 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 amplifiers and precision signal chains.

The THS3125IDR belongs to TI's THS312x family of low-noise, high-output-current current-feedback amplifiers, designed specifically for demanding video, test equipment, and industrial actuator drive applications where bandwidth, drive strength, and distortion performance are critical.

FAQ

What is the recommended power supply configuration for THS3125IDR in video distribution applications?

The THS3125IDR operates optimally with ±15-V dual supplies for video distribution, delivering its full 128-MHz bandwidth, 1550-V/µs slew rate, and –80 dBc THD at 1 MHz. At ±15 V, it achieves 26-VPP output swing into 50 Ω and maintains <0.01% differential gain error across 75-Ω serially terminated loads - meeting NTSC/PAL broadcast specifications. Lower supplies (e.g., ±5 V) reduce bandwidth and output swing but may suffice for lower-resolution or DC-coupled instrumentation uses.

How does the REF pin affect shutdown behavior in THS3125IDR?

The REF pin on THS3125IDR defines the reference voltage for the SHUTDOWN pin's enable/disable thresholds. When REF is tied to ground, the device enables below 0.8 V and disables above 2.0 V on SHUTDOWN. If REF is biased to an intermediate voltage (e.g., +5 V), the thresholds shift accordingly (enable at REF + 0.8 V, disable at REF + 2 V), allowing adaptive shutdown control across varying supply rails. THS3125IDR's REF pin accepts voltages from VCC− to VCC+ − 4 V, ensuring robust operation across its ±5 V to ±15 V range.

Can THS3125IDR drive 50-Ω loads continuously at full output swing?

Yes, THS3125IDR is rated for continuous ±450 mA output current and delivers ±13.3 V (26.6-VPP) into 50 Ω at ±15 V supplies - verified under thermal conditions with proper PowerPAD™ soldering to a ≥2-in² copper pour. Its HTSSOP-14 PowerPAD™ package achieves θJA = 37.5°C/W, enabling 3.3 W power dissipation. Without adequate thermal relief, junction temperature rise exceeds safe limits; TI Technical Brief SLMA002 specifies minimum pad size and via count for sustained 450-mA operation.

What is the purpose of the N/C pins on THS3125IDR's HTSSOP-14 package?

The N/C pins (5, 7, 8, 10) on THS3125IDR are unconnected die bond pads with no internal circuitry. They must remain electrically floating - not tied to ground, supply, or any signal - and should not be routed or stubbed on the PCB. Connecting or routing traces to these pins risks parasitic coupling, degraded high-frequency performance, or ESD susceptibility. Their presence reflects package reuse across the THS312x family; THS3125IDR uses only 11 of the 14 pins for functional operation.

How does THS3125IDR's current-feedback architecture differ from conventional voltage-feedback op amps in layout practice?

THS3125IDR's current-feedback topology demands strict layout discipline: the inverting input (1 IN−, 2 IN−) must be placed adjacent to the output (1 OUT, 2 OUT) with minimal trace length and no vias, as it serves as a low-impedance summing node sensitive to parasitic inductance. Feedback resistors (RF) must be surface-mount, placed directly between output and inverting input, with ground return paths avoiding shared traces. Unlike voltage-feedback op amps, gain is set by RF alone (not ratio), so RF tolerance directly impacts bandwidth stability - TI recommends 1% metal-film resistors for G = 2 configurations.