Texas Instruments THS3122CDDAR

Overview

THS3122CDDAR from Texas Instruments is a dual-channel, bipolar-input current feedback amplifier optimized for high-output-current, low-distortion video and instrumentation signal paths. 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 clean amplification of 26-VPP signals into 50-Ω loads for broadcast-grade video distribution.

For engineers reviewing the THS3122CDDAR datasheet, THS3122CDDAR pinout, THS3122CDDAR application, or THS3122CDDAR equivalent, this page provides verified package mapping (HSOP-8 PowerPAD), validated dual-amplifier pin functions, confirmed noise/distortion specs at ±5 V and ±15 V supplies, and real-world selection guidance against functionally aligned alternatives.

Technical Context

The THS3122CDDAR 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 sourcing/sinking ±450 mA while maintaining –80 dBc THD at 1 MHz and 2 VPP.

Unlike voltage-feedback amplifiers, its bandwidth remains stable across gains ≥2 due to fixed feedback resistor optimization (e.g., 470 Ω for G = 2). The HSOP-8 PowerPAD package integrates a thermal pad tied to VCC− for enhanced power dissipation - critical for sustaining 1.87 W at +25°C ambient without derating.

Key Specifications

Pinout & Package

THS3122CDDAR is housed in an 8-pin HSOP (PowerPAD) package (body size 4.89 mm × 3.90 mm) with an exposed thermal pad on the underside electrically and thermally connected to VCC−. Proper PCB layout requires soldering this pad to a large copper pour tied to the negative supply plane for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with THS3122CD and THS3092ID, THS3122CDDAR uniquely balances 450-mA drive, 2.2-nV/√Hz noise, and PowerPAD thermal performance - making it the only option among the three qualified for continuous 26-VPP video distribution into 50-Ω loads at commercial temperature.

Availability

THS3122CDDAR is available at Aetrix Electronics and suitable for video distribution, instrumentation signal conditioning, and high-speed line driving applications requiring stable component supply, long-term manufacturability, and guaranteed thermal performance in compact HSOP packages.

Supply support for THS3122CDDAR 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 high-performance signal chain solutions.

The THS3122CDDAR belongs to TI's THS312x family of low-noise, high-speed current feedback amplifiers - engineered specifically for demanding video, test equipment, and precision actuator applications where output drive, bandwidth, and noise must coexist at industry-leading levels.

FAQ

What is the maximum continuous output current specification for THS3122CDDAR?

The THS3122CDDAR is rated for ±450 mA continuous output current per channel under recommended operating conditions (TA ≤ +70°C, proper thermal layout). Absolute maximum rating is ±550 mA, but sustained operation above ±450 mA risks exceeding junction temperature limits unless thermal design exceeds the HSOP-8 PowerPAD's 67°C/W θJA rating. Data sheet Figure 26 confirms 440 mA output into 25 Ω at ±15 V supply with <1 V drop.

Does THS3122CDDAR support single-supply operation?

Yes, THS3122CDDAR supports single-supply operation from 10 V to 30 V (VCC+ to GND), as specified in Section 7.3 Recommended Operating Conditions. However, its input common-mode range (VICR) is limited to within 2.7 V of either rail - so with a 15-V single supply, VICR spans 2.7 V to 12.3 V. For rail-to-rail input capability or true GND-referenced signals, external level-shifting or biasing is required.

How does the THS3122CDDAR differ from the THS3125 in pin compatibility and functionality?

THS3122CDDAR and THS3125 are not pin-compatible. THS3122CDDAR uses an 8-pin HSOP package with no SHUTDOWN or REF pins, while THS3125 uses 14-pin HTSSOP with dedicated SHUTDOWN and REF terminals. Functionally, THS3122CDDAR lacks shutdown mode - it operates continuously whenever powered. THS3125 adds 370-µA shutdown current and programmable threshold control via the REF pin, but sacrifices package compactness and thermal efficiency (θJA = 37.5°C/W for PWP vs 67°C/W for DDA).

What is the typical input bias current for THS3122CDDAR at ±15 V supply?

At ±15 V supply and TA = +25°C, the typical input bias current for THS3122CDDAR is 2 µA on the noninverting input (IN+) and 23 µA on the inverting input (IN−), per Section 7.6 Electrical Characteristics: DC Performance. This asymmetry arises from the current feedback architecture's internal transistor biasing - the inverting input connects directly to a low-impedance node, resulting in higher bias current than the high-Z noninverting input.

Can THS3122CDDAR drive a 50-Ω load with 20-VPP output while maintaining low distortion?

Yes - THS3122CDDAR delivers 26-VPP output into 50 Ω at ±15 V supply (Section 7.8 Output Voltage Swing), and achieves –80 dBc THD at 2 VPP and –75 dBc at 8 VPP (Section 7.5 Noise and Distortion). While distortion increases with output amplitude, –75 dBc at 8 VPP confirms usable linearity up to that level. For 20-VPP, THD degrades to approximately –67 dBc (inferred from Figure 16 trend), which remains acceptable for many instrumentation applications but falls short of broadcast video requirements (<–70 dBc).