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SKU: LSK 389B SOIC 8L Category:


LSK 389B Ultra Low Noise JFET

The LSK389 is Linear Systems’ premier ultra-low-noise part. This monolithic, N-Channel dual JFET is available in four Idss grades and is used in a variety of ultra-high-end audio and sensor applications.

This product corresponds to two pieces of LSK 170B and they are completely matched in the same capsule.


Polarity: N
(VGDS ) : 40 V
Max (IDSS):  12 mA
Min (IDSS):  6 mA
Vgs(off): 0,5 V
(PD): 400 mW
Capsel: SOIC 8L
RoHS Compliant: Yes


Data Sheet

Application Note

LSK 170 and LSJ 74 is a classic transistor. Toshiba once launched the 2SK170/2SJ74 but they are no longer available. Nowadays, Linear Systems manufactures these products.
These low-noise transistors are found in many professional devices, but there are also lots of constructions for the DIY market. A truly classic application is the phono amplifier, which requires a low noise figure.

Linear Systems presents a full line of single, dual, N-Channel and P-Channel ultra-low-noise JFETs to create low-noise, high-performance applications ranging from sensors to audio amplifiers. Members of the company’s design and production staff each have over 40 years’ experience making these parts, and as a group they are the most talented working in this area today.

Linear Systems has unique expertise in designing and producing monolithic dual JFETs, with related intellectual property dating back to the beginning of the company over 30 years ago. Monolithic dual JFETs have a very real and significant thermal tracking advantage over two discrete die selected for match in the same package. Selecting two dice for VGS match isn’t hard, but it is far more difficult to select VGS match over a temperature span.

Linear Systems’ monolithic dual designs overcome the typical problem with this approach – parasitic capacitance – to create the highest performance parts in their class. Our proprietary JFET designs also create the lowest noise parts of their type in the industry.


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