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< Back Low Leakage Diodes Introduction In circuit designs for sensor signal conditioning, the design engineer must protect the input section from over current and over voltage conditions. Op amps, ADC analog inputs, analog multiplexers, and [RS485] line receivers represent classes of devices that need protection. Often, the manufacturers of such devices specify the acceptable input range for voltage, or, in the case of an overvoltage condition, the allowable input current above which semiconductor or bonding wires may be damaged. Read More

< Back LS844 App Note Introduction Introduction For circuits designed to work with high impedance sources, ranging from electrometers to microphone preamplifiers, the use of a low-noise, high-impedance device between the input and the op amp is needed in order to optimize performance. At first glance, one of Linear Systems’ most popular parts, the LSK389 ultra-low-noise dual JFET would appear to be a good choice for such an application. The part’s high input impedance (1 T) and low noise (1 nV/√Hz at 1kHz and 2mA drain current) enables power transfer while adding almost no noise to the signal. But further examination of the LSK389’s specification shows an input capacitance of over 20pF. This will cause intermodulation distortion as the circuit’s input signal increases in frequency if the source impedance is high. This is because the JFET junction capacitances are nonlinear. This will be especially the case where common source amplifier arrangements allow the Miller effect to multiply the effective value of the gatedrain capacitance. Further, the LSK389’s input impedance will fall to a lower value as the frequency increases relative to a part with lower input capacitance. A better design choice is Linear Systems’ LS844. Though the LS844 has slightly higher noise (2.5 nV/√Hz vs. 1.0 nV/√Hz) its much lower input capacitance of only 4pF means that it will maintain its high input impedance as the frequency of the input signal rises. More importantly, using the lower-capacitance LS844 will create a circuit that is much less susceptible to intermodulation distortion than one using the LSK389. The LS844’s lower gate-to-drain capacitance enables more effective, elegant audio circuit designs. The relatively high capacitance of the LSK389 often requires designers to use a cascode circuit to provide the ability to handle higher bandwidths without intermodulation distortion. The cascode does this by eliminating the Miller effect that can multiply the effective gate-drain capacitance and its associated nonlinear effects. However, the cascode adds complexity and noise contributed by the cascode transistors. The LS844 is an N-channel dual low-noise, lowcapacitance, tightly matched monolithic field effect transistor. It features: • 3ms transconductance at 2mA drain current • 1000 G input impedance • 60V breakdown voltage • gate-drain capacitance of only 1.5pF • 4pF input capacitance • 2.5 nV/√Hz noise at 1kHz • best low-noise/low-capacitance combination in the industry • lowest input capacitance per unit gate length in the industry • lowest noise for a given gate length in the industry • tight Vgs matching at operating bias The LS844 is particularly well suited to low-noise, highgain audio and instrumentation circuits operating from battery voltages up to 60 volts. 48V phantom-powered circuits, like those used in microphone preamplifiers, are especially benefited by the features of the LS844. Low operating Vgs, high gm, tight matching, low noise and low capacitance make it well-suited to numerous audio and instrumentation applications. Sensors, which play such an important role in today’s world, benefit greatly from the performance delivered by the LS844. Such sensor technologies include piezo, quartz, condenser, electret, and MEMs devices. These devices benefit from the LS844’s combination of low input capacitance and low noise. Electrometer applications also benefit from these characteristics. Read More

< Back DMOS App Note Introduction This Application Note describes in detail the principle of operation of the SD210/5000 series of high-speed analog switches and switch arrays. It contains an explanation of the most important switch characteristics, application examples, test data, and other application hints. Read More

LOW LEAKAGE, MONOLITHIC DUAL, PICO-AMP DIODE < Back DPAD/SSTDPAD Series JPAD SERIES SINGLE, PICO AMP, LOW LEAKAGE DIODES The DPAD Series Low Leakage, Monolithic Dual, Pico-Amp Diode is a direct replacement for the Siliconix-Vishay part series. It is ideal for Pico Amp, Ultra Low Leakage, Protection Diode Applications. This part series is available in the TO-72 4L RoHS, TO-78 5L RoHS and SOIC 8L 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: DPAD1 TO-72 4L RoHS DPAD2 TO-72 4L RoHS DPAD5 TO-72 4L RoHS DPAD10 TO-72 4L RoHS DPAD20 TO-72 4L RoHS DPAD50 TO-72 4L RoHS DPAD100 TO-72 4L RoHS DPAD1 TO-78 5L RoHS DPAD2 TO-78 5L RoHS DPAD5 TO-78 5L RoHS DPAD10 TO-78 5L RoHS DPAD20 TO-78 5L RoHS DPAD50 TO-78 5L RoHS DPAD100 TO-78 5L RoHS DPAD1 SOIC 8L RoHS DPAD2 SOIC 8L RoHS DPAD5 SOIC 8L RoHS DPAD10 SOIC 8L RoHS DPAD20 SOIC 8L RoHS DPAD50 SOIC 8L RoHS DPAD100 SOIC 8L RoHS DPAD1 Die DPAD2 Die DPAD5 Die DPAD10 Die DPAD20 Die DPAD50 Die DPAD100 Die Datasheet Spice Model Application Notes

GENERAL PURPOSE < Back LS190 GENERAL PURPOSE The LS190 is a General Purpose Single N-Channel JFET Amplifier. This part is available in the TO-92 3L package, as well as the SOT-89 3L package. 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. Datasheet Spice Model Application Notes

< Back High Temp Products Linear Systems Mar 17, 2023 High Temp Discrete Products High Temperature Product Capability Original Post: https://www.prnewswire.com/news-releases/linear-systems-to-showcase-high-temperature-product-capability-at-the-offshore-technology-conference-2019-300839508.html FREMONT, Calif., April 29, 2019 /PRNewswire/ -- Linear Integrated Systems, Inc. (Linear Systems) will be showcasing its High Temperature Products capability at the Trendsetter Electronics Booth #4728 , at the Offshore Technology Conference (OTC) being held May 7 through May 9 at the NGR Park, Houston, Texas. These High Temperature Discrete Products enable designers to create custom discrete operational amplifiers when seeking a solution to improve the performance of their applications, when off the shelve operational amplifiers are not good enough. The Linear Systems' JFET product line is one of the largest in the industry and continues to expand. The unique Linear Systems' monolithic dual construction allows for two JFETs to be located on one piece of silicon, as compared to two individual pieces of silicon. The result is improved room temperature matching as well as improved matching/tracking over high temperature. Linear Systems' JFETs are available in various types: Ultra Low Noise (1.9nv-typ), High Impedance, Pico Amp Leakage, and High Frequency. The JFET product line includes both N-Channel Monolithic Duals and Singles and P-Channel Monolithic Duals and Singles for Amplifier and Switching Applications. Linear Systems will be available to discuss this capability and its line of precision small-signal discrete components at the OTC event. The event showcases offshore drilling, exploration, production and environmental protection manufacturers. Linear Systems specializes in the development and manufacture of precision, ultra-low-noise small-signal discrete components. Its parts, such as the LSK389 and LSK489, are used in highly demanding sensor systems ranging from the Large-Scale Synoptic Telescope to piezoelectric devices to sonobuoys. These parts also provide the front-end amplification for down hole, high-end test and measurement, sensor, medical and professional audio equipment. Linear Systems is a full-service, privately-held, 32-year-old 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 consists of: Ultra-Low-Noise JFETs: N-Channel and P-Channel Monolithic Dual and Single, High-Speed Lateral DMOS Switches, Bipolar Transistors : Monolithic Dual and Single, BIFET Amplifiers, Current-Regulating Diodes, Pico Amp-Leakage Diodes, MOSFETs: N-Channel and P-Channel Monolithic Dual and Single, PhotoFETS, and Voltage Controlled Resistors. Data sheets, application notes, SPICE models and other information can be downloaded at linearsystems.com . For more information about Linear Systems please contact Ms. Laura Madonna at laura@linearsystems.com . For customer service, please contact Linear Systems at sales@linearsystems.com or call (510) 490-9160. SOURCE Linear Integrated Systems Related Links www.linearsystems.com

SINGLE, HIGH FREQUENCY, N-CHANNEL JFET AMPLIFIER < Back J/SST/U308 Series SINGLE, HIGH FREQUENCY, N-CHANNEL JFET AMPLIFIER The J/SST/U308 Series Single, High Frequency, N-Channel JFET Amplifier is a direct replacement for the Fairchild, NXP and Siliconix-Vishay equivalent part. It is ideal for High Frequency Applications. The series is available in the TO-92 3L RoHS, TO-18 3L RoHS and SOT-23 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: J308 TO-92 3L RoHS J309 TO-92 3L RoHS J310 TO-92 3L RoHS U308 TO-18 3L RoHS U309 TO-18 3L RoHS U310 TO-18 3L RoHS SST308 SOT-23 3L RoHS SST309 SOT-23 3L RoHS SST310 SOT-23 3L RoHS U308 Die U309 Die U310 Die Datasheet Spice Model Application Notes

< Back Military Sensor Signal Chains Introduction Higher-performance sensors are becoming increasingly important to modern battlefield systems. Sensors ranging from sonobuoys to radiation detectors are critical, leading-edge components of C4ISR systems. Better sensor systems enable earlier threat detection and more effective countermeasures. Military systems employ a wide range of sensors – nuclear, biological, and chemical sensing, infrared, electro-optical, laser, radar, and acoustical – that all have one aspect in common: the requirement for ultra-low-noise signal chains to produce the best possible sensor signal. Less-than-optimal front-end amplification means C4ISR clients receive inadequate information and are not able to make effective, real-time decisions. This paper describes techniques to employ to create the lowest-noise, most effect front-end amplification for sensor signal chains. Advanced lithography design and fab process techniques enable the creation of discrete components uniquely capable of performing the critical initial amplification of sensor signals. Integrated circuits contain a wide range of components and can include specialized design features that preclude design optimization for low noise. As this paper documents, ultra-low-noise discrete components added to an IC-based circuit will produce the lowest-noise signal chain. Though this paper focuses on the LSK489 dual monolithic Nchannel JFET, many other Linear Systems parts -- including the LSK389, LSK170 and LSK189 -- also are excellent sensor system components. Linear Systems is the world leader in ultra-low-noise monolithic dual JFETs and other front-end discrete components key to high-performance sensing systems. For over three decades, Linear Systems has led the development of this class of devices, and it continues to advance their design and introduce new sensor-specific parts. Read More

< 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.

SINGLE, LOW LEAKAGE PICO-AMP DIODES < Back J/SST/PAD Series SINGLE, LOW LEAKAGE PICO-AMP DIODES The PAD Series Ultra-Low Leakage, Protection Diode is a direct replacement for the Siliconix-Vishay part series. It is ideal for Pico Amp, Ultra-Low Leakage, Protection Diode Applications. This part series is available in the TO-72 3L RoHS, TO-92 2L 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: PAD1 TO-72 3L RoHS PAD2 TO-72 3L RoHS PAD5 TO-72 3L RoHS PAD10 TO-72 3L RoHS PAD20 TO-72 3L RoHS PAD50 TO-72 3L RoHS PAD100 TO-72 3L RoHS JPAD5 TO-92 2L RoHS JPAD10 TO-92 2L RoHS JPAD20 TO-92 2L RoHS JPAD50 TO-92 2L RoHS JPAD100 TO-92 2L RoHS SSTPAD1 SOT-23 3L RoHS SSTPAD2 SOT-23 3L RoHS SSTPAD5 SOT-23 3L RoHS SSTPAD10 SOT-23 3L RoHS SSTPAD20 SOT-23 3L RoHS SSTPAD50 SOT-23 3L RoHS SSTPAD100 SOT-23 3L RoHS PAD1 Die PAD2 Die PAD5 Die PAD10 Die PAD20 Die PAD50 Die PAD100 Die Datasheet Spice Model Application Notes

Linear Systems designs and manufactures the highest-performance line of monolithic dual JFETs in the industry. Contact us for a quote! Back SST/U421 Series LOW LEAKAGE, LOW DRIFT, MONOLITHIC DUAL, N-CHANNEL JFET The SST/U421 Series Low-Noise, Low-Drift, Monolithic Dual N-Channel JFET Amplifier is designed for a broad spectrum of precision instrumentation and sensor applications. This series is offered in TO-71 6L, TO-78 7L, PDIP 8L, and SOIC 8L RoHS-compliant packages, 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 The following options are available for ordering this part series: U421 TO-71 6L RoHS U422 TO-71 6L RoHS U423 TO-71 6L RoHS U424 TO-71 6L RoHS U425 TO-71 6L RoHS U426 TO-71 6L RoHS U421 TO-78 7L RoHS U422 TO-78 7L RoHS U423 TO-78 7L RoHS U424 TO-78 7L RoHS U425 TO-78 7L RoHS U426 TO-78 7L RoHS SST421 SOIC 8L RoHS SST422 SOIC 8L RoHS SST423 SOIC 8L RoHS SST424 SOIC 8L RoHS SST425 SOIC 8L RoHS SST426 SOIC 8L RoHS U421 Die U422 Die U423 Die U424 Die U425 Die U426 Die Datasheet Spice Model Application Notes

< Back CMR Ratio in Dual JFETs Introduction When choosing the optimal JFET for a new circuit, a characteristic often overlooked is how the part’s design affects the rejection of unwanted inputs while amplifying the signal as accurately as possible. Single JFETs provide excellent impedance matching and low-noise amplification, but lack one important quality of their dual counterparts – dual discrete devices largely reject common signals. This important characteristic – Common Mode Rejection – means that selecting the right dual JFET can be the most cost-effective way of improving signal-to-noise ratio in a design. Read More