Introduction
The dual monolithic P-channel LSJ689 is the complement to the N-channel LSK489. Both devices feature low offset, low noise and low capacitance. They enable the efficient implementation of fully complementary input stages without many of the device matching requirements when pairs of discrete devices are employed. Used alone, the LSJ689 also enables the implementation of more traditional differential input stages in applications where P-channel devices are preferred.
Features of the LJ689 include:
Low noise on the order of 2 nV/Hz
Low gate-drain capacitance, typically 3pF
Low gate leakage current typically 3pA (Vds = 15V, Id = 1mA) Breakdown voltage of 50V o IDSS range of 5-20 mA
Typical transconductance of 3mS at Id = 1mA
This note covers the full-complementary input stage application for the LSJ689 in combination with the LSK489.