Texas Instruments THS4021IDR

Overview

THS4021IDR from Texas Instruments is a single-channel, ultra-low-noise (1.2nV/√Hz), high-speed voltage-feedback operational amplifier optimized for precision analog signal conditioning in demanding wideband applications. It delivers 290MHz small-signal bandwidth at gain = 10V/V, 470V/μs slew rate, and 30ns settling time (0.1%), with stable operation at gains ≥10V/V and ±4.5V to ±16V dual-supply support - ideal for ultrasound front-end amplification and source measurement unit (SMU) current/voltage sensing stages.

For engineers reviewing the THS4021IDR datasheet, THS4021IDR pinout, THS4021IDR application, or THS4021IDR equivalent, this page provides verified technical context, validated pin functions, real-world application mappings, and confirmed alternative options for low-distortion, high-drive amplifier selection in medical imaging, test equipment, and power quality instrumentation.

Technical Context

The THS4021IDR employs a voltage-feedback architecture with offset nulling pins (Pins 1 and 8) enabling precise DC calibration in closed-loop configurations. Its stability at minimum gain of 10V/V eliminates need for external compensation networks in fixed-gain high-speed buffer or gain-stage designs.

It achieves ultra-low input voltage noise (1.2nV/√Hz) and low total harmonic distortion (–68dBc at 1MHz, RL = 150Ω), supported by high output drive capability (200mA typical) and rail-to-rail output swing (±12.9V into 250Ω at ±15V supplies), making it suitable for driving ADC inputs and active filter stages without signal degradation.

Key Specifications

Pinout & Package

THS4021IDR is packaged in an 8-pin SOIC (D package), with thermal resistance R_θJA = 124.5°C/W. The device features offset nulling capability via dedicated pins and requires no external compensation for gains ≥10V/V.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed, low-noise operational amplifier applications.

Compared with OPA656U and LMH6629MA, THS4021IDR uniquely balances ultra-low noise, high slew rate, gain stability at 10V/V, and on-chip offset nulling - making it optimal for applications requiring simultaneous precision DC performance and wideband AC fidelity.

Availability

THS4021IDR is available at Aetrix Electronics and suitable for ultrasound scanner front ends, source measurement units (SMUs), and power quality meters requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for THS4021IDR 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-performance op-amps and precision signal-chain solutions.

The THS402x family was designed specifically for ultra-low-noise, high-speed analog signal conditioning in medical imaging, automated test equipment, and energy monitoring systems - prioritizing noise floor, distortion, and settling behavior over general-purpose utility.

FAQ

What is the minimum stable gain for THS4021IDR?

The THS4021IDR is specified as stable at gains ≥10V/V and ≤–9V/V. This means it does not require external compensation components when configured as a noninverting amplifier with gain of 10 or higher, or as an inverting amplifier with magnitude ≥9. Attempting to use THS4021IDR at lower gains may result in peaking or oscillation unless compensated per TI's Application Report SLOA057.

Does THS4021IDR support single-supply operation?

Yes, THS4021IDR supports single-supply operation from 9 V to 32 V. When operated single-ended, the input common-mode range extends to within 1.2 V of the negative rail and 1.7 V below the positive rail (e.g., VICR = 1.2 V to 13.3 V at VCC = 15 V), and output swing reaches within 1.1 V of each rail under light load. Designers must bias inputs appropriately and verify headroom for their specific gain configuration.

How do I use the NULL pins on THS4021IDR?

Pins 1 and 8 are offset null inputs. Connect a 10 kΩ potentiometer across them, with its wiper tied to VCC–. Adjusting the potentiometer changes the internal input stage bias, reducing input offset voltage to as low as 0.3 mV (typical). This is especially valuable in DC-coupled SMU voltage source stages where residual offset directly impacts accuracy.

What is the maximum output current capability of THS4021IDR?

THS4021IDR delivers 200 mA (typical) continuous output current into resistive loads, with absolute maximum rating of 240 mA. At ±15 V supplies and RL = 10 Ω, it sustains ±12.9 V swing while sourcing/sinking up to 200 mA. Thermal derating applies above ambient temperatures of 70°C; junction temperature must remain ≤150°C, requiring appropriate PCB copper area or heatsinking for sustained high-current operation.

Is THS4021IDR suitable for driving ADC inputs?

Yes, THS4021IDR is well-suited for driving SAR and pipeline ADC inputs due to its 30 ns (0.1%) settling time, low distortion (–68 dBc), and ability to deliver full-scale swing into typical ADC input impedances (e.g., 1 kΩ || 10 pF). Its 290 MHz bandwidth ensures minimal phase delay across baseband frequencies, and its 1.2 nV/√Hz noise contributes negligibly to overall system noise floor when paired with 14–16-bit converters.