Flat Package, whose base material is Kovar, is mainly used for intensively assembled hybrid integrated circuits, which is suitable for surface mounting.
Frame leads or cylindrical leads are introduced from one side, two sides or four sides of package.
Compared with Uni-body Plug-in Package which has the same size, distance between two leads of flat package could be closer up to 1.27mm. As a result, more leads could be realized and the maximum could be more than 180 leads.
Package could be entirely gold plated or surface nickel plated and leads gold plated. Applied sealing method of Uni-body Plug-in package is parallel seam welding, and etched step type lids are used as package covers.