the TO-3 but smaller TO-92: Plastic-encapsulated package with three leads TO-99: Metal can package with eight radial leads TO-100 TO-126: Plastic-encapsulated package with three leads and a hole for mounting on a heat sink TO-220: Through-hole plastic package with a (usually) metal heat sink tab and three leads TO-226 TO-247: Plastic-encapsulated package with three leads and a hole for mounting on a heat sink TO-251: Also called IPAK: SMT package similar to the DPAK but with longer leads for SMT or TH mounting TO-252: (also called SOT428, DPAK): SMT package similar to the DPAK but smaller TO-262: Also called I2PAK: SMT package similar to the D2PAK but with longer leads for SMT or TH mounting TO-263: Also called D2PAK: SMT package similar to the TO-220 without the extended tab and mounting hole TO-274: Also called Super-247: SMT package similar to the TO-247 without the mounting hole Dimension reference Surface-mount C Clearance between IC body and PCB H Total height T Lead thickness L Total carrier length LW Lead width LL Lead length P Pitch Through-hole C Clearance between IC body and board H Total height T Lead thickness L Total carrier length LW Lead width LL Lead length P Pitch WB IC body width WL Lead-to-lead width Package dimensions All measurements below are given in mm. To convert mm to mils, divide mm by 0.0254 (i.e., 2.54 mm / 0.0254 = 100 mil). C Clearance between package body and PCB. H Height of package from pin tip to top of package. T Thickness of pin. L Length of package body only. LW Pin width. LL Pin length from package to pin tip. P Pin pitch (distance between conductors to the PCB). WB Width of the package body only. WL Length from pin tip to pin tip on the opposite side. Dual row Quad rows LGA Multi-chip packages A variety of techniques for interconnecting several chips within a single package have been proposed and researched: SiP (system in package) PoP (package on package) 3D-SICs, Monolithic 3D ICs, and other three-dimensional integrated circuits Multi-chip module WSI (wafer-scale integration) Proximity communication By terminal count Surface-mount components are usually smaller than their counterparts with leads, and are designed to be handled by machines rather than by humans. The electronics industry has standardized package shapes and sizes (the leading standardisation body is JEDEC). The codes given in the chart below usually tell the length and