Through-hole package

Bare Die Through-Hole Packages Module Assemblies... 

Caution Integrated circuits in through-hole packages are becoming difficult to find as they are displaced by surface-mount equivalents and should be avoided in new designs unless a secure supply of components is available for the production life of the design. 

Connectors comprise approximately 75 to 80 percent of odd-form components. See Fig. 40.6. For example, there are universal serial bus (USB) connectors, dual inline memory module (DIMM) connectors, phone jacks, and zero-insertion-force (ZIF) connectors, as well as a variety of surface-mount connectors. Other odd-form components include sockets, electrolytic capacitors, transformers or large inductors, LEDs, relays, switches, as well as speakers and vibrators for handheld communications devices. In surface-mount technology, odd-form components are most often through-hole packages, including both passive and active devices as well as connectors. When addressing such odd-form components, the first step is to check the availability of an equivalent surface-mount version since there has been a shift toward surface-mount versions of many of these devices. Of course, the materials used to construct the surface-mount replacement must survive the reflow furnace environment, and especially the Pb-free reflow temperatures, particularly connectors because of their complex internal construction. In some cases, it has been possible to replace the through-hole connector with one of a variety of solderless products. 

Measure off a length of fuse that wilt give the desired delay. Thread this through Hole in bottom of eoniainer so that it penetrates into the black pow der package. 

Insert fuse through hole In end of cardboard container Be sure It goes into Uack powder package. 

Thread fuse through hole in end cap and place package in end cap. Screw end cap onto pipe, being careful that black powder package is not caught between the threads ... 

Figure 4 shows an example of a pin grid array (PGA), developed to accommodate IC s with 84 or more pins. The original PGA s were ceramic packages, but several techniques are now used to produce them in plastic. The PGA s can be through-hole mounted on the printed wiring board, or can be socketed and surface mounted. 

For many years the standard package was the Dual In Line (DIP) and the plated through hole (PTH) glass... 

Fix package in envelope firmly and thread string through hole. 

FIGURE 8.128 Some typical IC packages for through-hole applications. 

In addition to bare die and surface mount techniques, there are still the older device packages for through-hole applications, where the lead of the package goes through the printed wiring board (see Fig. 8.128 and Fig. 8.129). Modules are also available that are assemblies of either packaged parts or die. 

Vertical mount package (VPAK), a package conceptuahy hke a zig-zag package (ZIP) except instead of through-hole leads it has surface-mount leads (L shaped leads). This package was introduced by Texas Instruments in late 1991 for 4- and 16-Mb direct random access memories (DRAMs). 

---