The LSK489 is a monolithic N-Channel JFET designed and built by Linear Integrated Systems, Inc.LIS Inc, a Fremont, CA company. The part was introduced in 2013[1] [2] and was named by EDN Tech as one of the “2013 EDN Hot 100” electronics industry innovations for the year.[3] In a product review published earlier that year, EDN noted:This JFET is part of a family of ultra-low-noise, dual JFET.[4]
The LSK489 is an N-channel monolithic dual JFET with 1.8 nV per square root Hz noise at 1 kHz and low-capacitance (Ciss= 4pF).[5] The part is not graded with respect to IDSS, with the typical value being 5 mA, a low of 2.5 mA and a high of 15 mA. Characteristics include:
The part achieves very low noise with respect to its transconductance, which is attributed to the producer's ability to eliminate almost all of the generation-recombination noise usually present in JFETs.[6] The part is available in TO-71, SOIC-A, and SOT-23 packages, as well as bare die.
The LSK489 (N-Channel Monolithic Dual JFET) and LSJ689[7] (P-Channel Monolithic Dual JEFT), also produced by Linear Integrated Systems, are complementary pairs. These two parts are the only complementary dual JFETs pair currently in production.[8] [9] The LSK489 is similar in electrical performance when compared to the LS843 series and the U401-403 series (Siliconix), the LSK489 has superior noise characteristics. It has slightly higher noise than the LSK389 (1.8 nV vs. 0.9 nV) but lower CISS (4pF vs. 20pF).[10] [11]
The LSK489 is used in a wide range of front-end signal chain applications, including audio preamps,[12] piezoelectric element preamps and photodiode preamps.[13] The part is also used in high-end sensor systems ranging from hydrophones to the front end of the Large Synoptic Survey Telescope (LSST) being developed by SLAC National Accelerator Laboratory.[14]