LSJ689 Press Release

Paul Norton, Marketing Director
Linear Integrated Systems, Inc.

115 KB PDF LSJ689 datasheet
950KB PDF LSJ689 Application Note
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FREMONT, CALIFORNIA - June 1, 2016 - Linear Integrated Systems, a leading full-service manufacturer of specialty linear semiconductors, announces the immediate availability of its LSJ689, a 1.8 nV/Hz @ 1kHz, low-capacitance, monolithic dual P-Channel JFET. The LSJ689 is a P-Channel complement to our monolithic dual N-Channel JFET, the LSK489. This latest addition to the Linear Systems family of Ultra-Low-Noise JFETs provides users with many more design options than available by using only N-Channel JFETs. Additionally, the monolithic dual construction of the LSJ689 and LSK489 provides better solutions for obtaining tighter Idss (drain-source saturation current) matching and improved thermal tracking than matching individual JFETs.

Historically, P-Channel JFETs availability has declined. Complementary Single N-Channel and P-Channel JFETs have become limited to a few industry standards. Complementary monolithic dual N-Channel and P-Channel JFETs have not been offered for many years, leaving designers under supported. In response, Linear Systems produced Single Complementary N & P Channel JFETs, the LSK170 and LSJ74 family. The LSJ689 and LSK489 provide additional options for designers. The LSJ689/LSK489 have 1/5 the capacitance of the LSK170 and LSJ74, 4pF versus 25pF. A unique Monolithic Dual design construction of interweaving each JFET on the same piece of silicon provide excellent matching and thermal tracking.

When used together, the LSJ689 and LSK489 are ideal for differential input stages for amplifier, phono, and preamplifier designs. Additional applications for the LSJ689 include voltage controlled resistors, thermal stable source followers, sample and hold, and current matched sources.

The LSJ689 is an ideal improved functional replacement for JFETs that have similar noise characteristics with reduced gate-to-drain capacitance. It is available in RoHS compliant SOT-23 6L, SOIC-A 8L and TO-71 6L package options. The LSJ689 SOT-23 6L and SOIC-A 8L packages are ideal for space-limited circuits in audio and instrumentation applications.

Summary of Features:

  • Complement to the Ultra Low Noise Monolithic Dual N-Channel JFET LSK489
  • Ultra Low noise (typically 1.8 nV/Hz @ 1kHz)
  • Nearly zero popcorn noise
  • Idss (drain-source saturation current) matching to 10% max
  • Low offset/tight matching (|Vgs1- Vgs2| = 20mV max)
  • Low capacitance (Ciss=4 pF)
  • High input impedance
  • High breakdown voltage (BVGSS = 40V Min)
  • Monolithic Dual (2 JFETS on one piece of silicon, better matching and thermal tracking)
  • Surface mount SOIC-A 8L versions and the smaller SOT-23 6L package
  • Lead-free/ROHS compliant


Microphone amplifiers, phono preamplifiers, audio amplifiers and preamps, discrete low-noise operational amplifiers, battery-operated audio preamps, audio mixer consoles, acoustic sensors, sonic imaging, and instrumentation amplifiers, wideband differential amplifiers, high speed comparators, impedance converters, voltage controlled resistors, sample and hold, source followers.

Price: US $8.66/ each (1,000+ pcs TO-71 6L)

Availability: Sampling now in SOIC-A 8L, TO-71 6L and SOT-23 6L package options

Delivery: Factory Stock


Linear Integrated Systems for assistance with application or special testing issues.

Toll Free 800-359-4023 Phone: 510-490-9160 Fax: 510-353-0261

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About Linear Integrated Systems
Linear Integrated Systems is a 29-year-old precision semiconductor company providing high-quality discrete components. Expertise brought to Linear Systems is based on processes and products developed at Amelco, Union Carbide, Intersil and Micro Power Systems by company founder John H. Hall. Hall, a protégé of Silicon Valley legend Dr. Jean Hoerni, was the director of IC Development at Union Carbide, co-founder and vice president of R&D at Intersil, and founder/president of Micro Power Systems.
Linear Systems is a U.S.-based, full-service manufacturer of specialty linear products with headquarters in Fremont, California. The company's small-signal discrete product lines are specifically designed to service the new design and second-source requirements of customers in the audio, hybrid, medical, space, test and measurement markets. The product line includes: BIFET Amplifiers, Bipolar Transistors, Current Regulating Diodes, JFETs, High Speed Lateral DMOS Switches, Low Leakage Diodes, and MOSFETs.
Linear Integrated Systems supplies pin for pin replacements for more than 2,000 discrete devices currently offered or discontinued by Interfet, Intersil, Micro Power Systems, Motorola, National, Fairchild, Toshiba, and Siliconix-Vishay.
Engineers are invited to contact Linear Integrated Systems for assistance with application or special testing issues.