TO-250 hermetic microelectronic packages can be manufactured in a variety of combinations.
They feature a cold-rolled-steel frame with hermetic seals made with alloy #52 or copper-cored alloy #52 pins in a compression glass seal or ceramic terminal. Bottom choices include OFHC copper, copper-moly, and copper-tungsten or glidcop. Braze material is 72% Ag, 28% Cu (BT braze).
CPS Technologies Corp., 111 S. Worcester St., Norton MA, 02766, (508) 222-0614, alsic.com