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When NXP discontinued the BF862, engineers around the world were left searching for a true low-noise replacement that preserved performance, ensured long-term supply continuity, and avoided expensive redesigns. Linear Integrated Systems is proud to introduce the LSBF862 , a precision N-channel JFET engineered not just to replace the BF862 — but to outperform it  across noise, breakdown voltage, and customizability. 👉 Read the full press release here: https://www.prnewswire.com/news-releases/linear-integrated-systems-introduces-lsbf862-superior-lower-noise-n-channel-jfet-replacement-for-discontinued-nxp-bf862-302630759.html?tc=eml_cleartime Why the LSBF862 Matters The discontinuation of the NXP BF862 created major challenges for designers working in audio, instrumentation, medical, sensing, and underwater acoustic applications. Many teams were forced into last-minute lifetime buys or faced the costly task of requalifying new components. The LSBF862 eliminates those risks — delivering improved performance and guaranteed long-term availability for your legacy and next-generation designs. Key Performance Advantages Ultra-Low Noise 4.0 nV/√Hz @ 10 Hz (Max): Perfect for ultra-low-signal environments, high-sensitivity amplifiers, and precision front-ends. Higher Breakdown Voltage Minimum BVGSS = 40V: Supports robust, stable operation in demanding analog circuits. High Gain & Low Capacitance Yfs = 45mS (typ) Ciss = 10pF (typ): Ideal for preserving signal fidelity and maximizing bandwidth. Radiation-Tolerant JFET Process Provides reliable behavior in harsh and mission-critical environments. Special Testing Options Available for Vgs(off)  and IDSS Supported in SOT-23 (3L)  and bare-die  formats. Perfect for engineers who require tighter specifications or matched performance. Where the LSBF862 Excels This device is purpose-built for high-precision analog applications, including: Low-Noise Amplifiers (LNAs) Discrete op amp designs Photo-diode and TIA stages High-impedance probes Acoustic and hydrophone preamps Battery-powered instrumentation Ultra-sensitive sensors Audio front-ends Medical electronics Test & measurement systems If your design demands low noise, stability, and long-term sourcing, the LSBF862 belongs in your evaluation pipeline. Pricing & Availability USD $1.35 each (1,000+ piece pricing) Samples and full production quantities available now Delivery:  Factory stock to 8 weeks Available directly through Linear Integrated Systems and our authorized distributors. 👉 REQUEST SAMPLES, DATASHEETS OR VOLUME PRICING HERE! A Word From Our CEO “The LSBF862 gives design engineers and procurement departments higher performance and long-term supply continuity.”— Cindy Johnson, CEO, Linear Integrated Systems Learn More Explore the full details in our official press release here:🔗 https://www.prnewswire.com/news-releases/linear-integrated-systems-introduces-lsbf862-superior-lower-noise-n-channel-jfet-replacement-for-discontinued-nxp-bf862-302630759.html?tc=eml_cleartime

When you’re trying to detect tiny signals at the bottom of the ocean, the front end of your signal chain can make or break the entire system. Towed arrays, hull-mounted sonars, and underwater acoustic modems all share one unforgiving requirement: you don’t get a second chance at the data . Once noise, drift, or mismatch pollutes a hydrophone’s output, there’s no DSP magic that can fully restore what’s been lost. That’s why so many designers working with hydrophones and piezoelectric transducers are turning to the LSK389 , a monolithic dual N-channel JFET engineered specifically for ultra-low-noise, high-integrity signal capture . Why the Front-End JFET Matters So Much Underwater Hydrophones and underwater acoustic sensors often deal with: Extremely low signal levels  from distant or low-amplitude sources Long cable runs  in noisy, harsh EMI environments Wide temperature swings , especially in deep or varying thermocline conditions High source impedance , which magnifies the impact of input noise and leakage In these systems, the very first active device — typically a JFET or JFET-input stage — sets the noise floor and stability for everything downstream. A poorly matched or noisy device at the front end can lead to: Elevated system noise floor Channel-to-channel mismatch across arrays DC offset drift that complicates calibration and beamforming Reduced detection range and degraded SNR This is exactly the class of problem the LSK389  is designed to solve. The LSK389: Built for Hydrophones & Acoustic Arrays The LSK389  is a monolithic dual JFET that delivers: Ultra-low thermal noise: Ideal for very low-level signals at the hydrophone output, helping extend detection range and preserve fine detail. Exceptional VGS tracking: Because both JFETs are on the same die, they track closely over temperature and time. This is especially important in differential and balanced front ends  common in towed array systems. Lower offset for cleaner, more stable baselines: Reduced offset makes it easier to calibrate and maintain stable references over long deployments, cutting down on re-trims and compensation complexity. High input impedance for piezoelectric sensors: The LSK389’s very high input impedance allows your hydrophones and transducers to operate as intended, with minimal loading and minimal loss of low-frequency information. Put simply: the LSK389 is designed to capture more of the ocean — and less of your own system noise. Ideal Applications in Underwater Acoustics The LSK389 is a strong fit anywhere low noise, high stability, and tight matching  are required, especially in: Towed array hydrophone preamplifiers Use the LSK389 as the input device in differential or charge amplifier topologies to maximize SNR and maintain consistent performance across many channels. Sonar front ends From passive listening systems to active sonar receive paths, the LSK389 helps ensure that reflections and echoes aren’t masked by front-end noise. Underwater acoustic modems Modems operating in noisy or bandwidth-constrained environments benefit from clean, low-noise analog front ends that preserve constellation integrity and reduce bit error rates. Transducer conditioning modules JFET-based front ends with the LSK389 can be used in compact, sealed modules right at the sensor to minimize cable-induced noise. Design Considerations: Getting the Best from the LSK389 While every design is different, here are a few general tips when using the LSK389 in hydrophone and acoustic applications: Leverage the monolithic dual Use both JFETs in matched configurations (differential pairs, cascoded stages, or balanced inputs) to take full advantage of tight VGS tracking. Pay attention to layout and shielding Even with a low-noise device, poor PCB layout or ground strategy can ruin performance. Keep sensitive nodes short, use solid ground planes, and route noisy digital lines away from the front end. Optimize biasing for your noise and bandwidth targets Bias current affects noise performance. Dial in your operating point for the best trade-off between noise, linearity, and power consumption. Control temperature where possible While the LSK389 is designed for stability, any analog front end benefits from good thermal management, especially in high-density array electronics. Try the LSK389 in Your Next Towed Array or Hydrophone Design If you’re designing: Towed arrays Hull-mounted sonar systems Distributed hydrophone networks Underwater acoustic modems or transducer modules …the LSK389  is an excellent candidate for your front-end JFET. We’re currently making the LSK389 available to evaluate at no cost , so you can see its performance in your own hydrophone or acoustic array design. 📩 Request samples here  and our team will follow up with you to get the right configuration into your lab.

For more than three decades, designers have turned to JFETs for their ability to deliver precision, low-noise performance in sensitive analog circuits. Unlike bipolar junction transistors (BJTs), which operate as current-controlled devices, JFETs function as voltage-controlled current sources , giving designers a unique balance of flexibility, stability, and ultra-high input impedance. Why JFETs Matter JFETs provide giga-ohm-level input impedances and picoamp-level input leakage currents — characteristics that make them ideal for applications demanding high sensitivity and low noise. These traits make them indispensable in instrumentation, sensor interfaces, and high-end audio designs. Key parameters engineers evaluate include: IDSS  (drain-source saturation current) VGS(OFF)  (pinch-off voltage) Gfs  (transconductance) en  (voltage noise density) CISS and CRSS  (input and reverse transfer capacitances) Each of these influences circuit gain, linearity, and noise performance — meaning design engineers often balance one characteristic against another to meet specific performance goals. Matched Dual JFETs for Precision Design When circuit matching and temperature tracking are critical — such as in differential amplifier stages — monolithic dual JFETs  are the best choice. Linear Integrated Systems’ matched pairs like the LSK389, LSK489, and LSJ689  are fabricated on the same chip, ensuring tight parameter tracking and ultra-low noise performance. These devices deliver exceptional common-mode rejection ratio (CMRR)  and minimal offset voltage, making them the preferred choice for low-noise amplifiers, sensor preamps, and precision audio front ends. Applications That Benefit from JFETs JFETs excel in both high-performance and low-power environments, including: Audio:  Microphone and phono preamplifiers for dynamic, ribbon, or electret transducers Instrumentation:  Vibration and piezoelectric sensor amplifiers Scientific and medical:  Photodiode, Geiger tube, or ECG/EKG front-end circuits Low-Power Designs:  Battery or energy-harvesting circuits powered by solar, thermal, or motion energy Beyond Amplification — Switching and Oscillation JFETs aren’t limited to amplification. They can also function as voltage-controlled resistors or switches , as in the LS26VPS , or serve in ultra-low-power oscillator circuits , such as those using the LSK170A . These designs can operate with supply voltages as low as 20 mV, making JFETs viable in applications where every microamp matters. In Summary From high-end audio and RF front ends to precision instrumentation and energy-scarce systems, JFETs remain unmatched for small-signal design flexibility and low-noise performance . Whether configured as amplifiers, oscillators, or variable resistors, Linear Integrated Systems’ JFETs provide the control, precision, and reliability engineers demand. 🔗 Learn more: LSK389 Series Datasheet, LSK489 Series Datasheet, LSJ689 Series Datasheet, Comparing JFETs Application Note

Ultra-Low Noise, High Input Impedance, N-Channel JFET Amplifier < Back LS BF862 Ultra-Low Noise, High Input Impedance, N-Channel JFET Amplifier The LSBF862 Single, Ultra-Low Noise, High Input Impedance, N-Channel JFET Amplifier is a direct, improved replacement for the discontinued NXP BF862. It is designed for applications requiring exceptional noise performance and high-impedance signal amplification. Engineered for precision and reliability, the LSBF862 provides superior noise characteristics, higher breakdown voltage, and greater flexibility through selectable testing and screening options. It is ideal for low-noise audio, acoustic, and sensor front-end applications. Available in the SOT-23 3L RoHS package, as well as in custom die form, the LSBF862 supports both legacy and next-generation designs. Key Features Ultra-Low 10 Hz Noise High Input Impedance, Low Capacitance Higher −40 V Gate-Source Breakdown Voltage Radiation Tolerant (No Special Hardening Required) Symmetrical Geometry — Source/Drain Interchangeable Special Testing Available for VGS, IDSS, and Other DC Parameters Benefits Superior Noise Performance for Audio, Acoustic, Instrumentation and Sensor Applications Seamless Drop-In Replacement for the BF862 — No Redesign Required Supports Repairs and Spares for Legacy Designs Available Customization by Specialized Screening and Selection Applications Audio & Acoustic Amplifiers Charge, Buffer, and Sample-and-Hold Circuits Discrete Operational Amplifiers Transimpedance Amplifiers (TIAs) Photodiode and Piezoelectric Preamplifiers Microphone, Hydrophone, and Sonar Front-Ends Medical Instrumentation: ECG, EEG, EKG, MRI, PET High-Impedance Probes and Spectrum Analyzers Frequently Asked Questions (FAQ) Is the LSBF862 a direct BF862 replacement? Yes. It is a drop-in, improved replacement with lower noise, higher breakdown, and long term availability. Is it in active production? Yes. Current available inventory of SOT-23 3 Lead package and Die Form, with no plans to discontinue. Is the LSBF862 available with special sorting or matching? Yes. 100% Special testing is offered Additional Special Screening & Customization Options Special screening is available across Linear Systems’ product lineup — including JFETs, MOSFETs, Bipolar Transistors, Current Regulators, and Diodes. Available in the SOT-23 3L RoHS package, as well as in die form. Connect with our technical team to tailor your requirements: Email support@linearsystems.com or call (510) 490-9160 MOQ applies to all specialized services. Click Here to Request Free LSBF862 Samples Ordering Information Below are the available configurations for the LSBF862 series: Standard Part Call-Out Select Part Call-Out (Select Parts Include SEL + 4 Digit Numeric Code) LSBF862 SOT-23 3L RoHS LSBF862 SOT-23 3L RoHS SELXXXX LSBF862 Die LSBF862 Die SELXXXX When ordering, include the full Linear Systems part number and package type. Custom screening selections (VGS, IDSS, etc.) available upon request. Datasheet Spice Model Application Notes

Linear Systems’ line of ultra-low-noise, low-noise and standard product JFET singles provide the industry’s widest range of design choices. JFET Amplifiers - Singles Linear Systems’ line of ultra-low-noise, low-noise and standard product JFET singles provide the industry’s widest range of design choices. LS BF862 Ultra-Low Noise, High Input Impedance, N-Channel JFET Amplifier Read More 2N/PN/SST4416 Series SINGLE, HIGH FREQUENCY, N-CHANNEL JFET AMPLIFIER Read More 4117DFN SERIES SINGLE, LOW CAPACITANCE, ULTRA-HIGH INPUT IMPEDANCE N-CHANNEL JFET AMPLIFIER - DFN Read More J/SST210 Series LOW NOISE N-CHANNEL JFET GENERAL PURPOSE AMPLIFIER Read More LSK170X ULTRA LOW NOISE, HIGH IDSS SINGLE N-CHANNEL JFET AMPLIFIER Read More LS190 GENERAL PURPOSE Read More LSK170 Series SINGLE, LOW NOISE, LOW CAPACITANCE, HIGH INPUT IMPEDANCE, N-CHANNEL JFET AMPLIFIER Read More 2N/PN/SST4117 Series SINGLE, LOW CAPACITANCE, ULTRA-HIGH INPUT IMPEDANCE, N-CHANNEL JFET AMPLIFIER Read More LSBF510 GENERAL PURPOSE, LOW-NOISE, LOW-COST, SINGLE N-CHANNEL JFET, REPLACEMENT FOR THE BF510 Read More LS/PF/SST5301 SINGLE, HIGH INPUT IMPEDANCE, N-CHANNEL JFET AMPLIFIER Read More LSK189 SINGLE, LOW-NOISE, LOW-LEAKAGE, N-CHANNEL JFET AMPLIFIERS Read More LS846 SINGLE, LOW-LEAKAGE, LOW-NOISE, N-CHANNEL JFET AMPLIFIER Read More LSJ/SST74 Series SINGLE, ULTRA-LOW NOISE, P-CHANNEL JFET AMPLIFIER Read More LSJ289 LOW NOISE, LOW CAPACITANCE SINGLE P-CHANNEL JFET Read More J/SST201 Series SINGLE, LOW NOISE, HIGH GAIN, N-CHANNEL JFET AMPLIFIER Read More J/SST/U308 Series SINGLE, HIGH FREQUENCY, N-CHANNEL JFET AMPLIFIER Read More LS5301 HIGH INPUT IMPEDANCE, N-CHANNEL JFET AMPLIFIER Read More

Linear Systems has been designing, manufacturing, and distributing high-performance JFET Amplifiers, DMOS Switches, Current Regulating Diodes, Bipolar Transistors, and JFET Switches since 1987. Our specialty semiconductors are recognized as the best in their class for precision, reliability, and performance. Building Excellence, One Part at a Time Since 1987, Linear Systems has been a leader in manufacturing specialty semiconductors. Operating from three Silicon Valley fabrication facilities, we serve a wide range of industries, including defense, aerospace, professional audio, and more. Our components are integral to applications such as military underwater surveillance, space telescope cameras, high-fidelity audio equipment, and advanced aerospace sensors. Our dedicated team is committed to delivering high-quality, reliable components, ensuring timely delivery to meet our customers' needs. Request a Quote Tailored Solutions to Meet Your Exact Specifications Get Started Connect with our expert technical team to discuss your project today: Call (510) 490-9160 or Email support@linearsystems.com How We Help You At Linear Systems, we understand that every application has unique demands. That’s why we offer advanced screening and customization options across our full product range, including N-Channel and P-Channel JFETs, High-Speed N-Channel Lateral DMOS Switches, Single and Quad Current-Regulating Diodes, Ultra Low-Leakage Diodes, NPN and PNP Bipolar Transistors, N-Channel and P-Channel Small Signal MOSFETs, and BIFET devices. Our advanced screening process allows for precise parameter selection, covering all specifications listed in our standard data sheets, including detailed package pin-outs. Whether you need tighter tolerances, specific performance metrics, or custom sorting, we can tailor our parts to meet your exact requirements. Let’s build exactly what you need. View Products High-Performance Components for Demanding Applications At Linear Systems, we specialize in precision analog components engineered for exceptional performance in the most demanding industries. Our flagship LSK series of ultra-low-noise JFETs—including the LSK389 and LSK170—delivers industry-leading noise performance trusted in critical applications worldwide. These monolithic dual and single N-Channel JFETs provide outstanding performance at competitive prices, complemented by a wide range of high-performance Improved Standard JFETs. For high-speed switching, our lateral DMOS switches set the standard for speed and reliability. Available as single and quad nanosecond switches with or without protection diodes, they enable fast, precise switching in demanding applications. Our PAD/JPAD/SSTPAD ultra-low-leakage diodes protect sensitive circuit inputs with leakage currents as low as -1 pA (PAD1). They’re ideal for op-amps, ADC analog inputs, analog multiplexers, and RS485 line receivers. The SST500 series of current-regulating diodes ensures consistent performance in high-reliability environments, such as test equipment, medical devices, and instrumentation. Using JFET technology, these diodes simplify circuit integration while maintaining precision. From precision JFETs to specialized diodes and switches, Linear Systems delivers components that meet the highest standards of performance and reliability. Explore our: Low-Noise JFETS Explore our: Low Leakage Diodes & Current Regulating Diodes Explore our: High-Speed DMOS Switches