< 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

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

< Back LSJ689 App Note Introduction The dual monolithic P-channel LSJ689 is the complement to the N-channel LSK489. Both devices feature low offset, low noise and low capacitance. They enable the efficient implementation of fully complementary input stages without many of the device matching requirements when pairs of discrete devices are employed. Used alone, the LSJ689 also enables the implementation of more traditional differential input stages in applications where P-channel devices are preferred. Features of the LJ689 include: Low noise on the order of 2 nV/Hz Low gate-drain capacitance, typically 3pF Low gate leakage current typically 3pA (Vds = 15V, Id = 1mA) Breakdown voltage of 50V o IDSS range of 5-20 mA Typical transconductance of 3mS at Id = 1mA This note covers the full-complementary input stage application for the LSJ689 in combination with the LSK489. Read More

< Back Jaime Cook: VP of Operations & Market Development Linear Systems Nov 21, 2024 Jaime Cook Appointed VP of Operations & Market Development at Linear Systems, Inc. Fremont, CA – October 1, 2024 – Linear Integrated Systems, Inc. is pleased to announce the appointment of Jaime L. Cook as Vice President of Operations and Market Development. In this pivotal role, Jaime will oversee all operational functions and spearhead market development initiatives. Jaime Cook has been a valued member of the Linear Systems team since 2009. Before stepping into her new role, Jaime served as Sales Manager, Director of Sales, and VP of Operations, gaining extensive experience across multiple facets of the company. Jaime brings a wealth of knowledge and expertise to her position as VP of Operations & Market Development. She holds bachelor's degrees in Real Estate and Land Use, as well as Strategic Management. Her education, certifications, and work experience have honed her skills in strategic planning, negotiation, and relationship building—qualities that significantly contribute to her expanded responsibilities at Linear Systems. “I’m incredibly proud to have built my career at Linear Systems and to be part of a team of exceptional individuals committed to producing the industry’s best specialty linear semiconductors while consistently meeting the highest standards of performance and reliability,” said Cook. “I am excited to expand my responsibilities, drive operational excellence, and lead efforts to explore new market opportunities.” Cindy L. Johnson, CEO of Linear Systems, stated, “Jaime’s leadership in operations and market development is pivotal as we aim to expand our product reach and strengthen customer relationships. Her strategic vision is vital to our mission of delivering ultra-reliable JFETs and other components that enable our clients to achieve outstanding performance in their designs.” Founded 37 years ago by John M. Hall, Cindy L. Johnson, and John H. Hall, Linear Integrated Systems, Inc. is a privately held designer and manufacturer of small-signal discrete semiconductors based in Fremont, CA. John H. Hall, a co-founder of Intersil and the founder of Micro Power Systems, brought significant expertise and innovation to the company. Linear Systems offers a diverse product line, including Dual JFET Amplifiers , Single JFET Amplifiers , JFET Switches , DMOS High Speed Switches , Low Leakage Diodes , Current Regulating Diodes , Bipolar Transistors , MOSFETs , Voltage Controlled Resistors and BIFET Amplifiers . Visit www.linearsystems.com to download our 2024 Data Book , Cross Reference Guide , datasheets, SPICE models, application notes , and more. Stay connected and join our growing LinkedIn community for updates and insights. You can also follow us on YouTube , Facebook , Instagram and X .

Learn about Linear Systems’ commitment to quality, including our ISO 9001 certified processes, rigorous testing, and focus on reliable, high-performance analog semiconductors. Quality At Linear Systems, quality is not just a standard; it's a commitment we uphold at every step of our operations. We are proud to have our quality management system certified to ISO 9001:2015, a testament to our unwavering dedication to excellence. Our commitment to quality is reflected in our rigorous internal audit processes, ensuring that every aspect of our operations meets the highest standards. Through our Continuous Improvement Program (CIP), we continuously review and refine our processes, building on past successes to implement best practices across the board. Our ultimate goal is zero defects, and we achieve this by conducting thorough failure analysis and root cause determination at every stage of development and production. By leveraging cutting-edge quality-analysis tools and methods, we ensure that our products consistently meet and exceed expectations. ISO Certificate

TIGHTLY MATCHED, MONOLITHIC DUAL, NPN TRANSISTOR < Back LS3250 Series - Dual TIGHTLY MATCHED, MONOLITHIC DUAL, NPN TRANSISTOR Previous Next

MONOLITHIC DUAL, PNP TRANSISTOR < Back IT130 Series MONOLITHIC DUAL, PNP TRANSISTOR The IT130 Series Monolithic Dual, PNP Transistor is a direct replacement for the Intersil IT130 Series. It is ideal for Small Signal Transistor Amplifier & Switching Applications. It is available the in TO-71 6L RoHS, TO-78 6L RoHS, PDIP 8L ROHS and SOIC 8L 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 st andard 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: IT130A TO-71 6L RoHS IT130 TO-71 6L RoHS IT131 TO-71 6L RoHS IT132 TO-71 6L RoHS IT130A TO-78 6L RoHS IT130 TO-78 6L RoHS IT131 TO-78 6L RoHS IT132 TO-78 6L RoHS IT130A PDIP 8L RoHS IT130 PDIP 8L RoHS IT131 PDIP 8L RoHS IT132 PDIP 8L RoHS IT130A SOIC 8L RoHS IT130 SOIC 8L RoHS IT131 SOIC 8L RoHS IT132 SOIC 8L RoHS IT130A Die IT130 Die IT131 Die IT132 Die Datasheet Spice Model Application Notes

< Back 3N163 App Note Introduction Wireless real-time radiation sensors networks offer the general public and those that work in high radiation areas greater protection against radiation hazards. Combined with real-time localized and global heat mapping of radiation levels, these radiation networks will help give government and environmental agencies the ability to understand the radiation landscape and respond quickly to radiation changes before they become life-threatening. Low-cost, low-power and no-power radiation sensors, also known as RADFETs (radiation field effect transistors) or dosimeters, are necessary for the implementation of these networks. The RADFET is unique because it does not need a power source to detect radiation. It is also unique in that it records the amount of actual radiation exposure and, as a non-volatile analog memory device, stores the level of radiation exposure as a change in threshold voltage. RADFETs are relatively simple circuits, consisting of only a PMOS transistor. The LS 3N163 PMOS (P-Channel) MOSFET transistor can be used to design RADFETs to meet different design requirements like cost, sensitivity, linearity, and power. The ability to optimize a RADFET for these different design requirements give network designers the ability to construct wireless radiation sensor networks that can also be optimized for cost and performance on a wide scale. Radiation detector principles PMOS MOSFET radiation detectors work on the principle that electron-hole pairs form when radiation or an ionizing particle strikes the MOSFET. This in turn results in shifts to the threshold voltage and drain current parameters of the MOSFET device. Because the change in threshold voltage with radiation exposure is highly linear in a PMOS device, PMOS devices such as the LS 3N163 are commonly used as a radiation detector. In a typical application, the LS 3N163 is operated in unbiased mode (no-power mode) and exposed to radiation. The change in threshold voltage is then measured and the corresponding radiation exposure level determined. In another application, where higher levels of sensitivity are needed, the LS 3N163 is operated in biased mode (power mode). 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

< Back Cloud Microphones Linear Systems Mar 17, 2023 Keeping the Family Business Going Cloud Microphones Among the more lamented departures from the world of electronics was RCA's microphone business. A few years ago I visited the college radio station where I'd worked in the 80s, and one of my former professors was proudly showing off an RCA 44A ribbon microphone the school had acquired. Though it had a few dents and scratches, it was a work of art. Soon after I saw it, the university's music department borrowed the mic for recording sessions and never gave it back. A typical RCA 44A ribbon microphone(Source: Wikipedia) Like original McIntosh MC275 amps, old ribbon microphones are collected because, when used correctly, they produce sounds hard to get elsewhere. But eventually even the vintage electronics section of eBay runs dry.One of the companies helping to provide new ribbon microphones and preamps, Cloud Microphones, has been able to continue the work RCA did through collaboration between a musician/businessman, Rodger Cloud, and Stephen Sank, son of RCA's ribbon microphone designer Jon R. Sank.Jon Sank had done design work at RCA that included the BK-10A and the BK-11. When he passed away in 1998, he left Stephen with the knowledge and other tools to continue the ribbon microphone work that RCA had left behind.Cloud came to Tucson as a singer/songwriter and started getting involved with bands and recording music. Sank moved into an office suite next door to Cloud's studio, and in 2006 they started working together.“So we collaborated on the initial designs of some of the mics, and I worked with him first refurbishing the vintage mics and so forth, and I really fell in love with the technology as it was in the 1930s and 1940s. It was just pretty darn great,” Cloud told me. “However, there were certainly challenges with the technology, most notably those types of microphones had a really weak sensitivity and are really difficult to deal with in terms of amplifying them.”Cloud said that even with exceptional amplifiers, it was very difficult to use ribbon microphones to record some softer sounds because of the gain requirements. This led Sank and Cloud to develop the JRS-34 ribbon microphone, named in honor of Sank's father and noting the year he was born. Rodger Cloud with his version of the RCA mic “As we worked on it, I really felt the need for an active microphone,” Cloud said. “And we really pushed ourselves to come up with something. We weren't just coming up with something that was OK. It had to be absolutely audiophile quality.” The result was a ribbon microphone that uses a Linear Systems LSK389 monolithic dual n-channel JFET to amplify the signal. Cloud wanted a dual JFET that would provide common-mode rejection in his amplifier, and settled on the LSK389. “It's just the JFET that we like the best. The power requirements for the circuit are low. We tested all of them, and this is the one that seemed to give us the results we were looking for.”Wiley Ross, who runs the recording studio at the University of Arizona, is a big fan of the Cloud's gear. “I use the Cloudlifter almost always when recording from a passive microphone,” he wrote in a recent email to me.“I don't use it because I need the gain, I have plenty with my Millennia Media HV-3R, but because the sound is better; richer, more depth,” Ross wrote. “With the Cloudlifter Z it's like having your mic locker expand to do all the different sonic possibilities afforded.”Ross added that Cloud's JRS-34 is a “main-stay” ribbon microphone. “I love it on all wind and brass instruments. Listening tests with other fine ribbons with faculty, students, and staff confirm its superiority.” The Cloudlifter Using a JFET-based circuit wasn't an obvious solution at first, Cloud said. “We were looking at several options with the microphones, and I was the one who suggested that we try the JFET technology. We were also looking at chip-based technology, different ways we could activate the mic. One of the problems with a chip-based design was we were going to have to use a couple of nine-volt batteries. We just couldn't figure out a way to get it to work on the phantom.”Using the Linear Systems' LSK389, which combines ultra-low noise with low IDSS , enabled Cloud and Sank to build a phantom-powered active ribbon microphone. Cloud said the prototype of the active circuitry was set up in a test box to enable testing various microphones. “And it only took a few moments to realize that this box is cool. And that's how the Cloudlifter accidently came to be.”The Cloudlifter is the active part of the company's ribbon microphone broken out into a format that can be used with many microphones people already have, and it soon became the company's best-selling product. “It's a game-changer, or more accurately a 'gain-changer,' because it allows people to use microphones that they normally would not even consider for softer sources, acoustic instruments, because the problem in the past has always been defeating the noise floor of the preamplifier.”The Cloudlifter is a standalone product customers could use to boost the gain of other microphones. It plugs into the line coming from a microphone and uses any standard phantom powered microphone input device to provide up to 25dB of “ultra-clean, transparent gain.”The Cloudlifter is recommended for: recording direct into a digital audio workstation interface; working with noisy or low gain preamps; using mixers/preamps that impair the sound at higher gain settings; working with passive ribbon microphones or low-output dynamic microphones; capturing softer sound sources such as acoustic instruments and voice; and when using long cable runs.When Cloud and his colleagues were first designing the circuit, they used Toshiba JFETs. “We found out about Linear Systems' products so we tried and we compared it,” says Cloud. “We liked it better than Toshiba. It was still an improvement, and I liked what it did for the Cloudlifter — it seemed to drop the noise floor even further, which is always a good thing when you're dealing with really low-sensitivity microphones.”Cloud said that after sales increased for the Cloudlifter, it became too labor intensive to match the single LSK170 JFETs. “It was becoming almost a full-time job to hand-match these little JFETs, so we started looking at the duals, and we went to the surface-mount technology, and I've got to say the Linear Systems duals are awesome. We can't match them that closely by hand, and the failure rate of the entire card as a whole is less than one in a thousand now. And we couldn't achieve that making them by hand.”The common-mode rejection enables the Cloudlifter to “pass clean audio in the worst of circumstances, next to a radio tower, in EMI hell,” according to Cloud.

SINGLE, LOW NOISE, HIGH GAIN, N-CHANNEL JFET AMPLIFIER < Back J/SST201 Series SINGLE, LOW NOISE, HIGH GAIN, N-CHANNEL JFET AMPLIFIER The J/SST201 Series Single, Low Noise, High Gain, N-Channel JFET Amplifier is a direct replacement for the Fairchild, NXP, and Siliconix-Vishay equivalent part. It is ideal for High Gain, Low Noise Applications. Available in the TO-92 3L 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: J201 TO-92 3L RoHS J202 TO-92 3L RoHS J204 TO-92 3L RoHS SST201 SOT-23 3L RoHS SST202 SOT-23 3L RoHS SST204 SOT-23 3L RoHS J201 Die J202 Die J204 Die Datasheet Spice Model Application Notes

< Back Interfacing Sensors & Transducers Introduction Abstract: A discussion of methods of amplifying and signal-conditioning for sensors with low level outputs in the presence of high ambient electrical noise sources. Advantages and disadvantages of some common amplifier circuits are considered. Read More