This part is a kind of semiconductor called LF398N.

Function of this product has Monolithic Sample-and-Hold Circuits.

Manufacturers : National Semiconductor

Image and pinout :

Some of the text within the PDF file :

LF198/LF298/LF398, LF198A/LF398A Monolithic Sample-and-Hold Circuits May 1998 LF198/LF298/LF398, LF198A/LF398A Monolithic Sample-and-Hold Circuits General Description The LF198/LF298/LF398 are monolithic sample-and-hold circuits which utilize BI-FET technology to obtain ultra-high dc accuracy with fast acquisition of signal and low droop rate. Operating as a unity gain follower, dc gain accuracy is 0.002% typical and acquisition time is as low as 6 µs to 0.01%. A bipolar input stage is used to achieve low offset voltage and wide bandwidth. Input offset adjust is accomplished with a single pin, and does not degrade input offset drift. The wide bandwidth allows the LF198 to be included inside the feedback loop of 1 MHz op amps without having stability problems. Input impedance of 1010Ω [ ... ]

LF398N PDF Datasheet Download