Texas Instruments THS4021IDGN

Overview

THS4021IDGN from Texas Instruments is a single-channel, ultra-low-noise (1.2 nV/√Hz), high-speed voltage-feedback operational amplifier optimized for precision analog signal conditioning in demanding applications. It delivers 290 MHz small-signal bandwidth at gain = 10 V/V, 470 V/µs slew rate, and 30 ns settling time (0.1%), with stable operation at gains ≥10 V/V and ±4.5 V to ±16 V dual-supply support - ideal for ultrasound front-end amplification.

For engineers reviewing the THS4021IDGN datasheet, THS4021IDGN pinout, THS4021IDGN application, or THS4021IDGN equivalent, key selection criteria include its offset-nulling capability, low distortion (–68 dBc at 1 MHz), high output drive (200 mA), thermal performance in HVSSOP-8 (R_θJA = 58.4 °C/W), and compatibility with ±5 V or ±15 V supplies in noise-critical measurement systems.

Technical Context

The THS4021IDGN employs a voltage-feedback architecture with internal compensation enabling unconditional stability at closed-loop gains ≥10 V/V. Its input stage uses a low-noise bipolar design achieving 1.2 nV/√Hz voltage noise and 2.3 pA/√Hz current noise above 10 kHz, while maintaining CMRR >95 dB and PSRR >95 dB at DC under ±15 V supply.

It features dedicated NULL pins (Pins 1 & 8) for external offset trimming, supports rail-to-rail output swing up to ±13.6 V into 1 kΩ (±15 V supply), and exhibits 350 MHz small-signal bandwidth in the DGN package variant - exceeding the 290 MHz spec of the SOIC version due to improved parasitic control.

Key Specifications

Pinout & Package

HVSSOP-8 (DGN) package: 3.0 mm × 3.0 mm, 0.5 mm pitch, exposed thermal pad, moisture sensitivity level 2a. Optimized for high-frequency layout with minimized lead inductance and controlled impedance routing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMH6629MA/NOPB and OPA656U, the THS4021IDGN uniquely combines offset-null capability, 200 mA drive, and 1.2 nV/√Hz noise - making it the only option among the three qualified for DC-coupled, high-current, low-noise instrumentation such as medical ultrasound receivers and precision SMUs.

Availability

THS4021IDGN is available at Aetrix Electronics and suitable for ultrasound scanner front-ends, source measurement unit (SMU) designs, and power quality meter signal chains requiring stable component supply, long-term manufacturability, and TI's industry-standard HVSSOP-8 packaging.

Supply support for THS4021IDGN 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 precision measurement instruments - emphasizing noise floor, settling behavior, and DC accuracy.

FAQ

What is the maximum small-signal bandwidth of the THS4021IDGN at gain = 10 V/V?

The THS4021IDGN achieves 350 MHz small-signal bandwidth (–3 dB) at gain = 10 V/V under ±15 V supply and RL = 150 Ω, as specified in Section 5.7 of the datasheet. This exceeds the 290 MHz typical value for the SOIC-packaged THS4021D due to reduced parasitics in the HVSSOP-8 (DGN) package, enabling higher-frequency closed-loop designs without stability compromise.

Does the THS4021IDGN require external compensation for stability?

No, the THS4021IDGN is internally compensated and guaranteed stable at closed-loop gains ≥10 V/V (or ≤–9 V/V) without external components. This eliminates the need for feedback capacitors or resistor networks in standard non-inverting or inverting configurations, simplifying layout and improving repeatability across production units.

How is offset voltage adjusted on the THS4021IDGN?

Offset voltage on the THS4021IDGN is trimmed using the dedicated NULL pins (Pins 1 and 8). A 10-kΩ potentiometer is connected with its wiper to Pin 1 and both ends to Pins 1 and 8, allowing manual adjustment to reduce input offset voltage to <0.5 mV - essential for DC-coupled applications like SMU force/sense stages.

What is the thermal resistance (RθJA) of the THS4021IDGN in its HVSSOP-8 package?

The THS4021IDGN in HVSSOP-8 (DGN) package has a junction-to-ambient thermal resistance (RθJA) of 58.4 °C/W, as measured per JEDEC JESD51-2 with 2 oz copper, 2-layer board, and no airflow. This value assumes proper thermal pad soldering to an internal ground plane; omitting the thermal pad increases RθJA by >20 °C/W.

Can the THS4021IDGN operate from a single 10-V supply?

Yes, the THS4021IDGN supports single-supply operation from 9 V to 32 V (Section 5.3). At 10 V, it delivers usable output swing (±3.3 V into 150 Ω), 280 MHz bandwidth at gain = 10, and maintains –69 dBc THD at 1 MHz - making it viable for portable or cost-sensitive instrumentation where dual supplies are impractical.