Texas Instruments THS4021CDR

Overview

THS4021CDR from Texas Instruments is a single-channel, ultra-low-noise (1.2 nV/√Hz), high-speed voltage-feedback operational amplifier optimized for ≥10 V/V gain-stable applications requiring wide bandwidth (290 MHz at G=10), fast settling (30 ns to 0.1%), and high output drive (200 mA). It serves as a precision signal conditioning front-end in ultrasound scanner analog beamforming paths.

For engineers reviewing the THS4021CDR datasheet, THS4021CDR pinout, THS4021CDR application, or THS4021CDR equivalent, this device is selected when low input voltage noise, high slew rate (470 V/μs), stable operation at minimum gain of 10 V/V, ±4.5 V to ±16 V dual-supply flexibility, and offset nulling capability are required in high-fidelity measurement and imaging signal chains.

Technical Context

The THS4021CDR employs a voltage-feedback architecture with a 2 GHz gain-bandwidth product and is internally compensated for stability at closed-loop gains ≥10 V/V (or ≤–9 V/V). Its design centers on minimizing input-referred noise while maintaining high slew rate and low distortion-critical for preserving signal integrity in wideband acquisition systems.

It features dedicated offset nulling pins (Pins 1 and 8) enabling precise DC calibration without external components, and delivers rail-to-rail compatible output swing (±12.9 V into 250 Ω at ±15 V supplies) while drawing only 7.5 mA per amplifier. The amplifier's 2.3 pA/√Hz current noise and –68 dBc THD at 1 MHz further support high dynamic range applications.

Key Specifications

Pinout & Package

THS4021CDR is packaged in an 8-pin SOIC (D package), with thermal resistance R_θJA = 124.5 °C/W. This surface-mount package supports automated assembly and provides mechanical robustness for industrial and medical-grade PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA656U and LMH6629MA, THS4021CDR uniquely balances ultra-low noise, 470 V/μs slew rate, guaranteed stability at G ≥ 10 V/V, and on-chip offset nulling-making it the only option among the three suitable for calibrated, wideband, medium-gain instrumentation where both AC fidelity and DC accuracy are simultaneously required.

Availability

THS4021CDR is available at Aetrix Electronics and suitable for ultrasound scanner front-ends, source measurement unit (SMU) force/sense circuits, and power quality meter signal chains requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for THS4021CDR 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 engineered specifically for demanding wideband instrumentation applications-including medical imaging, automated test equipment, and energy analytics-where low noise, high speed, and DC precision must coexist.

FAQ

What is the minimum stable gain for THS4021CDR?

The THS4021CDR is internally compensated for unity-gain stability only at gains ≥10 V/V (or ≤–9 V/V). Operating at lower gains (e.g., G = 2 or G = 5) risks peaking, overshoot, or oscillation unless external compensation is applied per TI Application Report SLOA057. Always verify phase margin using the open-loop gain/phase plot (Figure 5-8) for custom gain configurations.

Does THS4021CDR support single-supply operation?

Yes, THS4021CDR supports single-supply operation from 9 V to 32 V. Input common-mode range extends to within 1.2 V of the negative rail and 1.7 V of the positive rail (e.g., VICR = 1.2 V to 30.3 V at VCC = 32 V), enabling true single-supply use with proper level-shifting of input/output signals. Refer to Section 5.3 Recommended Operating Conditions for biasing guidelines.

How do I use the NULL pins on THS4021CDR?

Connect a 10 kΩ potentiometer between THS4021CDR Pins 1 and 8, with its wiper tied to VCC–. Adjusting the potentiometer nulls input offset voltage to typically <0.3 mV at 25°C. Avoid capacitive loading on these pins, and ensure PCB traces are short and symmetric to prevent noise pickup. Do not leave Pins 1 or 8 floating or connected to other nodes.

What is the maximum output current capability of THS4021CDR?

THS4021CDR delivers 200 mA (typical) continuous output current into low-impedance loads (e.g., 10 Ω) at ±15 V supplies, with absolute maximum rating of 240 mA. Sustained output currents above 100 mA require attention to thermal dissipation-junction temperature must remain ≤150°C. Use the R_θJA = 124.5 °C/W value for SOIC to calculate allowable power dissipation in your layout.

Is THS4021CDR suitable for driving ADC inputs directly?

Yes, THS4021CDR is commonly used to drive SAR and sigma-delta ADC inputs due to its 30 ns settling time (0.1%), 200 mA output drive, and low distortion (–68 dBc THD). For optimal performance, match output impedance (via series resistor) to ADC input capacitance, maintain clean ground return paths, and avoid exceeding the ADC's specified input voltage range-especially when operating near rail limits.