New Ultra Low Noise Monolithic Dual JFETs (Audio Microphones, Amplifiers, Acoustic Sensors)

Paul Norton, Marketing Director
Linear Integrated Systems, Inc.

115 KB PDF LSK389 datasheet
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FREMONT, Calif. - January 12, 2006 - Linear Integrated Systems, a leading full-service manufacturer of specialty linear semiconductors, announces the immediate availability of its LSK389 series of 1nV N-Channel Monolithic Dual JFETs.  A monolithic dual version of the recently released LSK170 Single N-Channel JFET. this family of ultra low noise dual JFETs was specifically designed to provide users a better performing, less time consuming, and cheaper solution for obtaining tighter IDSS matching, and better thermal tracking, than matching individual JFETs.  Available packaged in surface mount, ROHS compliant versions, the LSK389 is an ideal improved functional replacement for the through-hole Toshiba 2SK389, within space limited circuits for audio and instrumentation applications.

The LSK389's features incorporates three grades of IDSS:  2.6-6.5mA, 6.0-12mA, 10-20mA, with an IDSS match of 10%, a gate threshold offset of 20mV, a voltage noise (en) of 1nv/hz @ 1khz, 2nv/hz @ 10hz typical, with a Gain of 22ms, and 22pf of capacitance.

Great for maximizing battery operated applications by providing a wide output swing, and a high signal to noise ratio as a result of the LSK389's tightly matched gate threshold voltages and low gate threshold voltages.  The uniquely linear VGS transfer function is highly desirable for producing low intermodulation in audio front-ends.  The 40 volt breakdown provides maximum linear headroom in high transient program content amplifiers.  The LSK389 provides a low input noise to capacitance product that has nearly zero popcorn noise.  The narrow ranges of the IDSS electrical grades combined with the superior matching performance of the LSK389's monolithic dual construction promote ease of device tolerancing in low voltage applications, as compared to matching single jfets.  Additionally, LIS offers custom screening for users who require different ranges of IDSS, VGS or other DC parameters than found in the datasheet.

Packaged in surface mount SOIC-8 and thru-hole TO-71 packages.  Lead-Free, ROHS compliant versions are available.

Now a Domestic Source for Low Noise JFETs

"Our new LSK389 series features a unique design construction of interleaving both JFETs on the same piece of silicon that provides excellent matching and thermal tracking, as well a low noise profile having nearly zero popcorn noise," says Dr. John Hall, Linear Integrated Systems founder and president.

Linear Integrated Systems domestic in-factory stock guarantees short lead times, ensuring no disruption in production schedules.

Summary of Features:

  • Low Noise (en <1 nv/hz @ 1khz, 2 nv/hz @ 10hz typ)
  • Nearly Zero Popcorn Noise
  • Availability in narrow IDSS grades/ranges (2.6-6mA, 6.0=12mA and 10-20mA)
  • IDSS matching to 10% max
  • Low Offset/Tight Matching (|Vgs1- Vgs2| = 20mV max)
  • Low Capacitance (20pf typ)
  • High Input Impedance
  • High Gain (Yfs = 22mS typ)
  • High Breakdown Voltage (BVGSS = 40V Min)
  • Improved Functional replacement (not pin for pin) for Toshiba 2SK389
  • Surface mount SOIC versions (not offered by Toshiba 2SK389)
  • Lead-Free ROHS Compliant versions available

Audio amplifiers and preamps, discrete low-noise operational amplifiers, battery-operated audio preamps, audio mixer consoles, acoustic sensors, sonic imaging, instrumentation amplifiers, microphones, sonobouys, hydrophones, chemical and radiation detectors.

Price: US$3.00 each (1,000 pcs.)

Availability: Sampling now in SOIC-8, and TO-71 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



About Linear Integrated Systems Linear Integrated Systems, Inc. is a U.S.-based, full service manufacturer of specialty linear products founded in 1987 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 DMSO 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.

Linear Integrated Systems has more than 35 years of design and process expertise in JFET and transistor manufacturing.  The company's founder, Dr. John Hall, has an established track record of leadership within various segments of the semiconductor industry, including the founding of Intersil and Micro Power Systems, development of the first 1 Volt CMOS digital watch and numerous related semiconductor patents.

Engineers are invited to contact Linear Integrated Systems for assistance with application or special testing issues.