Texas Instruments THS3122CDDA

Overview

THS3122CDDA from Texas Instruments is a dual-channel, bipolar-input current feedback amplifier in HSOP-8 PowerPAD™ package, delivering 450 mA output current drive, 128-MHz –3-dB bandwidth (RL = 50 Ω), 1550-V/µs slew rate (G = 2), and ultra-low 2.2-nV/√Hz voltage noise. It enables high-fidelity video distribution and precision instrumentation where heavy loads demand low distortion across wide bandwidth.

For engineers reviewing the THS3122CDDA datasheet, THS3122CDDA pinout, THS3122CDDA application, or THS3122CDDA equivalent, key selection criteria include its dual-channel current-feedback architecture, ±5 V to ±15 V dual-supply operation, 2.9-pA/√Hz noninverting input current noise, 26-VPP output swing into 50 Ω, and thermal performance enabled by the exposed PowerPAD™ die attach pad.

Technical Context

The THS3122CDDA implements a current feedback topology with high-impedance noninverting inputs and low-impedance inverting inputs, enabling stable gain-setting with wideband response independent of closed-loop gain. Its transimpedance gain stage drives a Class-AB output buffer capable of sourcing/sinking ±450 mA continuously.

It operates as a true dual amplifier with fully isolated channels-no shared bias networks or internal crosstalk paths-and features matched DC parameters (≤4 mV channel offset voltage matching) and rail-to-rail output swing capability under heavy load conditions (e.g., 13.3 VPP into 50 Ω at ±15 V supplies).

Key Specifications

Pinout & Package

THS3122CDDA uses the HSOP-8 PowerPAD™ (DDA) package: 4.89 mm × 3.90 mm body with thermally enhanced exposed copper pad on underside, requiring PCB thermal via array for junction temperature control.

Key Features

Applications

Equivalent & Alternatives

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

Compared with THS3122CD and THS3092ID, THS3122CDDA uniquely combines PowerPAD™ thermal performance, 450-mA continuous output, and 2.2-nV/√Hz noise - making it the only option among the three qualified for high-current, low-noise, thermally constrained video and instrumentation line drivers.

Availability

THS3122CDDA is available at Aetrix Electronics and suitable for video distribution, instrumentation front ends, line drivers, and piezo drivers requiring stable component supply, long-term manufacturability, and guaranteed TI second-source availability.

Supply support for THS3122CDDA 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 company specializing in analog and embedded processing technologies, with leadership in high-performance amplifiers, data converters, and power management ICs.

The THS3122CDDA belongs to TI's THS312x family of low-noise, high-speed current feedback amplifiers, designed specifically for demanding analog signal paths in broadcast video, test equipment, and precision motion control where both wide bandwidth and high output current are essential.

FAQ

What is the maximum continuous output current specification for THS3122CDDA?

The THS3122CDDA is rated for ±450 mA continuous output current per channel into resistive loads, verified at TA = +25°C with proper thermal management via the PowerPAD™. This rating assumes adequate PCB copper area and thermal vias beneath the exposed pad to maintain junction temperature ≤125°C under full-load conditions. The absolute maximum rating is ±550 mA, but sustained operation above ±450 mA requires derating based on ambient temperature and heatsinking.

Does THS3122CDDA support shutdown functionality like THS3125?

No, THS3122CDDA does not include shutdown functionality. The SHUTDOWN and REF pins present on the THS3125 are no-connect (N/C) on THS3122CDDA and must be left unconnected or grounded per layout guidelines. Shutdown capability is exclusive to the THS3125 variant; THS3122CDDA operates in always-on mode with 8.4 mA per channel quiescent current at ±15 V supplies.

What is the recommended PCB layout practice for the PowerPAD™ on THS3122CDDA?

TI specifies that the exposed thermal pad on the THS3122CDDA HSOP-8 PowerPAD™ package must be soldered to a solid copper ground plane using an array of ≥6 thermal vias (0.3-mm diameter, spaced ≤1 mm apart) filled with solder. This achieves the specified θJA of 67°C/W. Failure to connect the pad results in θJA degradation to ~120°C/W, risking thermal runaway at >200 mA output current. No thermal compound or isolation is permitted between pad and PCB.

Can THS3122CDDA drive 50-Ω loads in unity-gain configuration without instability?

Yes, THS3122CDDA is unity-gain stable when driving 50-Ω loads, provided the feedback network uses the recommended RF = 750 Ω resistor and layout minimizes parasitic capacitance at the inverting input. Stability is confirmed by TI's typical characteristics showing flat small-signal gain response to 100 MHz at G = 1. For best results, place RF close to the IN− pin and use short, direct traces to avoid peaking or ringing in pulse responses.

What is the input common-mode voltage range for THS3122CDDA at ±15-V supplies?

At ±15-V supplies, the input common-mode voltage range for THS3122CDDA is ±12.5 V to ±12.7 V across the full temperature range (–40°C to +85°C). This allows direct interfacing with ±10-V industrial signal standards and accommodates headroom for internal biasing. Operation outside this range risks increased input offset voltage drift and degraded CMRR, particularly below –12.5 V or above +12.7 V.