Linear Systems Reintroduces LSK389 Ultra-Low Noise N-Channel JFET

February 26 2020, 00:20
Linear Systems has reintroduced its most popular part, the LSK389, which the Silicon Valley company calls the industry’s first 100% noise tested, ultra-low noise (en = 1.3nV/√Hz (typ), f = 1.0kHz and NBW = 1.0Hz), monolithic dual, n-channel JFET. New test capability screens to a billionth of a ​volt (​nV​/√Hz) of noise now ensures that all ​LSK389s devices produce no burst (RTN or popcorn) noise and ​meet or exceed 1/f and broadband noise specifications.

The LSK389 is the lowest noise Junction Field Effect Transistor (JFET) in its class and has been used in ultra-high-end audio applications for over a decade. The LSK389 enables developers to create the lowest noise signal chains possible for sensors, professional audio equipment and other applications. 

Now, Linear Systems is releasing the LSK389 after creating the capability for individual screening of small-signal discrete components to levels below a billionth of a volt (nV/√Hz) of noise in quantities up to tens of thousands of parts. This testing capability – the only one in existence worldwide – ensures all LSK389s leaving the factory produce no burst (RTN or popcorn) noise and meet or exceed 1/f and broadband noise specifications. 

"The LSK389, Ultra-Low Noise, Monolithic Dual, N-Channel JFET provides designers with a better-performing solution for obtaining tighter IDSS matching and better thermal tracking than using individual JFETs or non-monolithic dual JFETs," Linear Systems President Tim McCune says. The part is an ideal combination of high transconductance, ultra-low noise and relatively low input capacitance. 

The LSK389 is the lead part of Linear Systems’ family of low-noise JFETs. The LSK170 is the N-channel single version of the LSK389, and the LSJ74 is the P-channel counterpart to the LSK170. The N-channel dual LSK489 has slightly higher noise but lower input capacitance than the LSK389, and the LSJ689 is its P-channel dual counterpart. In addition to the LSK-series, all Linear Systems’ JFET standard products have substantially lower noise than those made by other manufacturers and are marketed under the Improved Standard Products trademark.

“The LSK389 is the key to building the world’s lowest-noise signal chains for many applications,” adds McCune. “Creating our new testing capability enables us to guarantee each part we ship meets our ultra-low noise spec, and that no manufacturer will ever have to scrap a circuit board because these parts didn’t work correctly.”

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 specializes in the development and manufacture of precision, ultra-low noise small-signal discrete components. Its parts 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 high-end test and measurement, medical and audio equipment. In addition to providing parts and technical support for new designs, Linear Systems supplies pin-for-pin replacements for more than 2,000 discrete devices currently offered or discontinued by National Semiconductor, Siliconix-Vishay, Intersil, Motorola, Fairchild and Toshiba.

Price: 1,000+ pieces of the LSK389A SOIC 8L package is $4.67 (USD) each. 1,000+ pieces of the LSK389A TO-71 6L package is $6.70 (USD) each. Prices vary based on grade (A, B, C and D) and quantity. Production quantities are available now.

Click here to download the application note: LSK389 Dual Monolithic JFET For Ultra Low Noise Applications by: Bob Cordell
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