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< Back FETs for Sensor Applications Introduction Linear Systems provides a variety of FETs (Field Effect Transistors) suitable for use in low noise amplifier applications for photo diodes, accelerometers, transducers, and other types of sensors. In particular, low noise JFETs exhibit low input gate currents that are desirable when working with high impedance devices at the input or with high value feedback resistors (e.g., ≥1MΩ). Operational amplifiers (op amps) with bipolar transistor input stages have much higher input noise currents than FETs. In general, many op amps have a combination of higher noise and input capacitance when compared to some discrete FETs. For example, a typical FET input op amp may have input capacitances of about 20 pF, whereas many discrete FETs have input capacitances of less than 5 pF. Also, there are few low noise FET input op amps that have equivalent input noise voltages density of less than 4 nV/ 𝐻𝑧. However, there are a number of discrete FETs rated at ≤ 2 nV/ 𝐻𝑧 in terms of equivalent Input noise voltage density. For those op amps that are rated as low noise, normally the input stages use bipolar transistors that generate much greater noise currents at the input terminals than FETs. These noise currents flowing into high impedances form added (random) noise voltages that are often much greater than the equivalent input noise. Read More

SINGLE, LOW NOISE, LOW CAPACITANCE, HIGH INPUT IMPEDANCE, N-CHANNEL JFET AMPLIFIER < Back LSK170 Series SINGLE, LOW NOISE, LOW CAPACITANCE, HIGH INPUT IMPEDANCE, N-CHANNEL JFET AMPLIFIER The LSK170 Single, Low Noise, Low Capacitance, High Input Impedance, N-Channel JFET Amplifier is a direct replacement for Toshiba 2SK170. It is ideal for Ultra Low Noise Audio/Acoustic Applications. Available in the TO-92 3L RoHS, SOT-23 3L RoHS and SOT-89 3L RoHS package, as well as in die form. Advanced screening options are available for our diverse product lineup, featuring JFETS, Bipolar transistors, MOSFETs, current regulators, and Diodes. Our special screening covers all the parameters listed in the standard datasheet, including comprehensive package pin-out. Connect with our experienced technical team to discuss your specific needs and tailor your requirements—email us at support@linearsystems.com or call (510) 490-9160. MOQ applies to these specialized services. Ordering Information Below are the options you have when ordering this part series: LSK170A TO-92 3L RoHS LSK170B TO-92 3L RoHS LSK170C TO-92 3L RoHS LSK170D TO-92 3L RoHS LSK170A SOT-23 3L RoHS LSK170B SOT-23 3L RoHS LSK170C SOT-23 3L RoHS LSK170D SOT-23 3L RoHS LSK170A SOT-89 3L RoHS LSK170B SOT-89 3L RoHS LSK170C SOT-89 3L RoHS LSK170D SOT-89 3L RoHS LSK170A Die LSK170B Die LSK170C Die LSK170D Die Datasheet Spice Model Application Notes

MONOLITHIC DUAL AND SINGLE, PNP TRANSISTOR < Back LS3550 Series MONOLITHIC DUAL AND SINGLE, PNP TRANSISTOR Previous Next

LOW NOISE, LOW CAPACITANCE SINGLE P-CHANNEL JFET < Back LSJ289 LOW NOISE, LOW CAPACITANCE SINGLE P-CHANNEL JFET The LSJ289 is a Low Noise, Low Capacitance, Single P-Channel JFET. Available in the TO-92 3L RoHS and SOT-23 3L RoHS package, as well as die form. Advanced screening options are available for our diverse product lineup, featuring JFETS, Bipolar transistors, MOSFETs, current regulators, and Diodes. Our special screening covers all the parameters listed in the standard datasheet, including comprehensive package pin-out. Connect with our experienced technical team to discuss your specific needs and tailor your requirements—email us at support@linearsystems.com or call (510) 490-9160. MOQ applies to these specialized services. Ordering Information Below are the options you have when ordering this part series: LSJ289 TO-92 3L RoHS LSJ289 SOT-23 3L RoHS LSJ289 Die Datasheet Spice Model Application Notes

MONOLITHIC DUAL, NPN TRANSISTOR < Back IT120 Series MONOLITHIC DUAL, NPN TRANSISTOR Previous Next

< Back What are Current Regulating Diodes Linear Systems Oct 7, 2024 Current regulating diodes, also known as constant current diodes or current limiting diodes, are electronic components that control the amount of electrical current flowing through a circuit. They work by maintaining a constant voltage across themselves despite changes in the load resistance. Current Regulating Diodes Current regulating diodes, also known as constant current diodes or current limiting diodes, are electronic components that control the amount of electrical current flowing through a circuit. They work by maintaining a constant voltage across themselves despite changes in the load resistance. How do they work? A standard diode allows current to flow freely in one direction and blocks it in the other direction. In contrast, a current regulating diode has a larger depletion region and a lower reverse breakdown voltage, which allows for more precise control of the current flow. When used in series with a load, the current regulating diode maintains a stable voltage drop across itself by varying its own resistance depending on the current flow. This means that as the load resistance changes, the voltage drop across the diode remains constant and therefore maintains a consistent current flow. Applications Current regulating diodes are commonly used in circuits where stable and precise current control is necessary, such as in LED lighting systems, battery charging circuits, and laser diode drivers. They can also be used as protection devices to limit the amount of current flowing through sensitive components. In addition, these diodes are often utilized in adjustable power supplies to regulate the output current and prevent damage to connected devices. Types of Current Regulating Diodes There are two main types of current regulating diodes: Zener diodes and avalanche diodes. Zener diodes operate in the reverse breakdown region, where they maintain a constant voltage despite changes in current flow. This makes them ideal for use as voltage regulators. Avalanche diodes, on the other hand, operate in the avalanche breakdown region and are used for higher voltage applications. They have a steeper current-voltage characteristic compared to Zener diodes, allowing for more precise control of the current flow. Advantages and Disadvantages The main advantage of using current regulating diodes is their ability to provide stable and accurate current control without the need for additional external components. This saves space and simplifies circuit design. However, one disadvantage is that these diodes can be sensitive to changes in temperature, which can affect their current regulation capabilities. In addition, they have a limited maximum current handling capacity, so they may not be suitable for high power applications. Conclusion In conclusion, current regulating diodes are essential components in many electronic circuits where precise and stable current control is necessary. They come in various types and offer advantages such as simplicity of use and compact size. However, care must be taken when using these diodes to ensure proper operation under different conditions. With continued advancements in technology, it is likely that we will see further improvements and developments in the field of current regulating diodes. So next time you encounter a circuit that requires precise current control, consider using a current regulating diode to achieve optimal performance. With their unique properties and benefits, these diodes are sure to play a significant role in the future of electronics. With the ever-growing demand for more efficient and reliable electronic devices, it is important to have a thorough understanding of different electronic components such as current regulating diodes. By having knowledge about their operation, advantages and limitations, you can make informed decisions when designing circuits for various applications. So keep exploring and learning about these fascinating components and discover new ways to incorporate them into your designs.

Discover an extensive array of application notes and white papers authored by the talented minds at Linear Systems, as well as contributions from our esteemed colleagues and friends. Immerse yourself in our carefully curated selection to stay informed and inspired. Articles & Books This is a space to tell users about yourself and your business. Let them know who you are, what you do, and what this website is all about. Double click to start editing. Articles FET Principles and Circuits, Part 1 to 4, by Ray Martson, Nuts and Volt 5/2000 Ray Marston Read More JFETs The New Frontier Part 1 Erno Borbely Read More Books Designing with Field Effect Transistors (Second Edition) 1990 ISBN 007057537-1 FET Technology and Applications 1989 ISBN 0824780507 View Read More Analog Circuit Design - A Tutorial Guide to Applications and Solution Analog Circuit Design, Volume 2 – Immersion in the Black Art of Analog Design Analog Circuit Design, Volume 3 – Design Note Collection View Read More An Introduction to Field Effect Transistors-by J. Watson PHD, University of Wales, Swansea-1970 Designing with Field Effect Transistors (First Edition) 1981 ISBN 9780070574496 View Read More Some Tips on Making a FETching Discrete Amplifier View Read More Designing Audio Power Amps, 2010, ISBN 007164024X The Audio Power Amplifier Design Handbook (Fifth Edition) View Read More Designing Audio Power Amps, 2010, ISBN 007164024X View Read More Piezoelectric Accelerometers with Integral Electronics includes noise analysis of JFET and MOSFET amplifier circuits ISBN 978-331908-0772 View Read More

SINGLE P-CHANNEL JFET SWITCH < Back LSJ/SST94 SINGLE P-CHANNEL JFET SWITCH The LSJ/SST94 Single, Ultra-Low noise, P-Channel JFET Amplifier is a direct replacement for the Toshiba 2SJ94. It is ideal for Ultra-Low Noise Audio/Acoustic Applications. Available in the TO-92 3L RoHS, SOT-89 3L RoHS, as well as in die form. Advanced screening options are available for our diverse product lineup, featuring JFETS, Bipolar transistors, MOSFETs, current regulators, and Diodes. Our special screening covers all the parameters listed in the standard datasheet, including comprehensive package pin-out. Connect with our experienced technical team to discuss your specific needs and tailor your requirements—email us at support@linearsystems.com or call (510) 490-9160. MOQ applies to these specialized services. Ordering Information: Below are the options you have when ordering this part series: LSJ94 TO-92 3L RoHS SST94 SOT-23 3L RoHS LSJ94 Die Datasheet Spice Model Application Notes

< Back LSK489 Press Release Linear Systems Mar 17, 2023 Low-Capacitance Dual N-Channel JFET NEWS RELEASE FOR INFORMATION CONTACT: Linear Systems, Inc. Sales Department Phone: (510) 490-9160 Email: sales@linearsystems.com Linear Systems Announces the Availability of the LSK489 Low-Noise, Low-Capacitance Dual N-Ch JFET Designed for All (Audio & Non-Audio) Low-Noise Applications FREMONT, CALIFORNIA – December 10, 2012 – Linear Systems, a leading full-service manufacturer of specialty linear semiconductors, announces the immediate availability of its LSK489 1.8 nV/√Hz @ 1kHz, low-capacitance, N-Channel Monolithic Dual JFET. This is part of a family of ultra-low-noise dual JFETs specifically designed to provide users with better-performing, less-time-consuming, and cost-effective solutions for obtaining tighter IDSS matching and better thermal tracking than matching individual JFETs. Available in surface-mount and RoHS-compliant versions, the LSK489 is an ideal improved functional replacement for similar JFETs with inferior noise characteristics and higher gate-to-drain capacitance, making it suitable for space-limited circuits in audio and instrumentation applications. The LSK489 offers designers a significant increase in capabilities for a wide range of low-noise applications. Its lower capacitance, 4pF compared to 25pF in similar products, enables simpler circuit designs without the need for a cascode configuration, which can introduce higher circuit noise. Like the LSK389, the LSK489 features a unique design construction of interleaving both JFETs on the same piece of silicon, providing excellent matching, thermal tracking, and nearly zero popcorn noise. The LSK489 is available in surface-mount SOIC-8, thru-hole TO-71, and smaller SOT23-6 packages. Lead-free, RoHS-compliant versions are available. Linear Systems' domestic factory stock guarantees short lead times, ensuring no disruption in production schedules. Summary of Features: - Low Noise (typically 1.8 nV/√Hz @ 1kHz) - Nearly Zero Popcorn Noise - IDSS matching to 10% max - Low Offset/Tight Matching (|Vgs1 - Vgs2| = 20mV max) - Low Capacitance (CISS = 4pF) - High Input Impedance - High Breakdown Voltage (BVGSS = 40V Min) - Low-noise, reduced device count alternative for the classic Dual JFET Cascode Configuration - Improved replacement for Siliconix U401 series and the Linear Systems 844 series - Available in surface-mount SOIC-8, smaller SOT23-6 packages - Lead-Free/RoHS Compliant versions available Applications: - Microphone amplifiers - Phono preamplifiers - Audio amplifiers and preamps - Discrete low-noise operational amplifiers - Battery-operated audio preamps - Audio mixer consoles - Acoustic sensors - Sonic imaging - Instrumentation amplifiers - Wideband differential amplifiers - High-speed comparators - Impedance converters Pricing and Availability: - Price: $5.38 each (1,000 pcs) - Availability: Sampling now in SOIC-8, TO-71, and SOT23-6 package options - Delivery: Factory Stock About Linear Systems Founded in 1987, Linear Systems is a full-service, privately-held designer and manufacturer of small-signal discrete semiconductors. The Fremont, CA-based company was founded by John H. Hall, co-founder of Intersil and founder of Micro Power Systems. Linear Systems' product line includes Ultra-Low-Noise N-Channel and P-Channel Dual and Single JFETs, High-Speed Lateral DMOS Switches, Bipolar Transistors, BIFET Amplifiers, Current-Regulating Diodes, Low-Leakage Diodes, and MOSFETs. Datasheets, application notes, SPICE models, and additional information can be downloaded at www.linearsystems.com. For more information, contact Linear Systems at sales@linearsystems.com or call (510) 490-9160.

< Back Bipolar Transistors Linear Systems Jul 16, 2024 Linear Systems’ Monolithic Dual NPN and PNP transistors consist of two transistors on the same piece of silicon resulting in better matching and better performance over temperature. These parts are designed for general purpose amplifier and switching applications. Bipolar Transistors by Linear Systems Bipolar transistors are electronic devices that can amplify or switch electric signals. They consist of three layers of a semiconductor material, each with different properties. The two most common types of bipolar transistors are NPN and PNP. Linear Systems is a company known for producing high-quality bipolar transistors. Founded in 1984, it has become one of the leading manufacturers in the industry. In this article, we will discuss the features and benefits of using bipolar transistors by Linear Systems. Features One of the key features of bipolar transistors by Linear Systems is their low noise and high gain characteristics. This makes them ideal for use in audio amplifiers and other applications where low distortion is critical. Another feature of Linear Systems' bipolar transistors is their high current handling capability. They are designed to handle large currents, making them suitable for power electronics applications. Benefits The low noise and high gain properties of Linear Systems' bipolar transistors result in improved signal quality and better performance in electronic circuits. This is especially important in communication systems, where even the slightest amount of distortion can cause significant issues. Furthermore, due to their high current handling capability, these transistors provide efficient power management in electronic devices. This leads to lower power consumption and longer battery life. Applications Linear Systems' bipolar transistors have a wide range of applications in various industries. Some common uses include: Audio amplifiers and preamplifiers Power supplies Switching circuits Motor control circuits LED drivers These transistors are also used in communication systems, such as cell phones, radios, and televisions. Conclusion In conclusion, Linear Systems' bipolar transistors offer superior performance and reliability compared to other options on the market. Their low noise and high gain characteristics make them ideal for critical applications where signal quality is essential. Additionally, their high current handling capability allows for efficient power management and longer battery life. With a track record of excellence in the industry, it is no surprise that Linear Systems' bipolar transistors are trusted and widely used in a variety of electronic devices and systems. So, these transistors are an excellent choice for engineers and designers looking for high-quality components for their electronic projects. So, next time you need a bipolar transistor, consider using one from Linear Systems to ensure optimal performance and reliability in your circuit design. With their advanced technology and commitment to quality, you can trust that Linear Systems' bipolar transistors will meet your needs and exceed your expectations. Overall, these transistors offer numerous benefits and have a wide range of applications, making them an essential component in many electronic systems. View our Bipolar Transistors

HIGH INPUT IMPENDANCE, SINGLE, BIFET AMPLIFIER < Back LS320 HIGH INPUT IMPENDANCE, SINGLE, BIFET AMPLIFIER The LS320 Single, high Input Impedance, BIFET Amplifier is a direct replacement for Amperex equivalent part. It is ideal for High Impedance Sensor Amplifier Applications. Available in the TO-72 4L RoHS, TO-92 3L RoHS and SOT-23 3L RoHS package, as well as bare die. Advanced screening options are available for our diverse product lineup, featuring JFETS, Bipolar transistors, MOSFETs, current regulators, and Diodes. Our special screening covers all the parameters listed in the standard datasheet, including comprehensive package pin-out. Connect with our experienced technical team to discuss your specific needs and tailor your requirements—email us at support@linearsystems.com or call (510) 490-9160. MOQ applies to these specialized services. Ordering Information Below are the options you have when ordering this part series: LS320 TO-72 4L RoHS LS20 TO-92 3L RoHS LS320 SOT-23 3L RoHS LS320 DIE Datasheet Spice Model Application Notes

< Back BIFET Amplifiers Linear Systems Sep 26, 2024 BIFET amplifiers are a type of operational amplifier (op-amp) that use bipolar junction field-effect transistors (BJFETs) as their input stage. Introduction BIFET amplifiers are a type of operational amplifier (op-amp) that use bipolar junction field-effect transistors (BJFETs) as their input stage. These types of amplifiers have been popular for many years because they offer low bias currents, high input impedance and excellent linearity. In this article, we will discuss the key features of BIFET amplifiers, how they differ from other op-amps, and some common applications where they are used. What is a BIFET Amplifier? As mentioned earlier, BIFET amplifiers use BJFETs as their input stage instead of traditional MOSFETs or BJTs. BJFETs are known for their high input impedance and low noise, making them suitable for use in audio amplifiers and other sensitive applications. One of the main advantages of BIFET amplifiers is their low bias currents, which can be as low as a few femtoamps (10^-15 amps). This allows for higher precision in measuring small signals without introducing additional error. How do BIFET Amplifiers Differ from Other Op-Amps? BIFET amplifiers have several key differences compared to traditional op-amps. These include: Input Stage: As mentioned earlier, BIFET amplifiers use BJFETs instead of MOSFETs or BJTs as their input stage. This allows for higher input impedance and lower bias currents. Biasing: BIFET amplifiers typically use a single positive power supply, unlike other op-amps which may require dual supplies. This makes them more convenient to use in certain applications. Output Stage: The output stage of a BIFET amplifier is usually a MOSFET or BJT, providing high output current and low output impedance. This allows for driving larger loads without significant signal loss. Applications of BIFET Amplifiers BIFET amplifiers are commonly used in audio applications due to their low noise and high linearity. They are also popular in medical and scientific instrumentation where precision measurements are required. Other applications of BIFET amplifiers include: Sensor Signal Conditioning: The high input impedance and low bias currents make BIFET amplifiers ideal for conditioning signals from sensors such as thermocouples, strain gauges, and photodiodes. Active Filters: BIFET amplifiers can be used to create active filters with better performance compared to traditional op-amps. They also have lower power consumption, making them suitable for battery-powered applications. Data Acquisition Systems: BIFET amplifiers are commonly used in data acquisition systems due to their low noise and high precision. They can amplify small signals from sensors before being digitized for processing. Conclusion BIFET amplifiers offer several advantages over traditional op-amps, making them suitable for a variety of applications. They provide high input impedance, low bias currents, and high output current capabilities. These features make BIFET amplifiers ideal for use in audio, sensor signal conditioning, active filters, and data acquisition systems. As technology continues to advance, we may see further improvements in BIFET amplifier design and their application in various industries. So, it is important to stay updated with the latest developments in this field to fully utilize the potential of BIFET amplifiers.