LSK389: The Ultimate Low-Noise Solution

JC - Linear Systems
Apr 15
3 min read

Updated: May 8

When designing ultra-sensitive analog systems, noise performance isn’t just a feature—it’s a necessity. At Linear Systems, we understand that low-noise discrete components are crucial for high-performance signal chains. This insight drives our LSK389 Series Ultra-Low Noise, Monolithic Dual N-Channel JFET, which has set the standard for engineers worldwide.

100% Noise Tested – The Industry First

Linear Systems' LSK389 is now 100% noise tested. This guarantees that it meets or exceeds both 1/f and broadband noise specifications. Using the world’s only large-scale sub-nanovolt testing capability, Linear Systems screens each unit to ensure:

No burst noise (RTN or popcorn)
Ultra-low noise performance down to 1.3nV/√Hz (typ)

Whether you're building high-end audio equipment, ultra-sensitive sensors, or low-noise op-amps, you can rely on consistent, production-grade noise performance.

Trusted in Underwater Acoustic Systems

The LSK389 and its single-device counterpart, the LSK170, are widely used in underwater acoustic applications. In these scenarios, extremely low-noise signal amplification is crucial. Common applications include:

Sonobuoys used in anti-submarine warfare (ASW)
Towed array sonar systems for naval surveillance
Hydrophones for marine research and underwater audio detection
Underwater modems and transducers for acoustic communication and navigation
Passive and active sonar systems used in defense and industrial marine applications

In these systems, signals travel farther and faster underwater than through air. JFET-based amplifier circuits are essential for capturing and processing these signals cleanly. The LSK389’s ultra-low noise, tight matching, and high input impedance make it a top choice for precision front-end amplifiers vital to sonar and underwater communications equipment.

Why the LSK389?

The LSK389 isn’t just another low-noise JFET. Its monolithic interleaved dual construction provides superior IDSS matching, better thermal tracking, and performance advantages over discrete or non-monolithic dual JFETs.

Key Features

Four IDSS grading options for design flexibility
Tight matching: IVGS1-2 ≤ 15mV max
High gain: Gfs = 20mS (typ)
Low capacitance: 25pF (typ)
Available in SOIC-8 and TO-71 packages

Part of a Complete Low-Noise JFET Family

The LSK389 is the cornerstone of our low-noise JFET lineup, which includes:

LSK170 – N-channel single version
LSJ74 – P-channel equivalent
LSK489 – N-channel dual (lower capacitance, slightly higher noise)
LSJ689 – P-channel dual version

Each component is part of Linear Systems' Improved Standard Products®. They provide lower noise than competitors’ equivalents, making them an ideal choice for engineers focused on performance.

Applications Beyond Underwater Systems

While the LSK389 excels in underwater acoustic systems, its applications extend into other fields as well.

High-End Audio Equipment

In high-fidelity audio systems, the clarity of sound is paramount. The LSK389 can significantly improve audio quality by minimizing unwanted noise. Its characteristics ensure that even the faintest sounds are captured with precision.

Sensitive Sensor Systems

For environmental monitoring, sensors used in industries like meteorology or oceanography require high sensitivity and low noise. The LSK389 ensures that these sensors perform optimally, delivering accurate data without interference from electronic noise.

Research and Development

In any R&D scenario where analog signal integrity is essential, the LSK389 proves invaluable. Researchers rely on its consistent performance to develop innovative solutions across various technologies.

Conclusion

Low-noise performance is critical in analog systems, and the LSK389 Series provides unparalleled performance. As it continues to serve multiple industries, the LSK389 remains a cornerstone for those who demand excellence.

📞 For more information, contact us at (510) 490-9160 or sales@linearsystems.com🌐 Visit: www.linearsystems.com