1.1.3. Foam for J-Lead Devices and QFP Devices in Carriers
Foam provides extra cushioning and restricts movement inside the tube to prevent device pins from bending. To support the devices evenly, the foam must be nearly as wide as the tubes. You must not use foam in any full tube containing special stoppers, as shown in the Proper Orientation of Special Stoppers figure. When you use the foam, place the foam at each end of the tube between the stoppers and devices, as shown in the following figure.
Foam must be antistatic, non-corrosive, and free of contaminants. Place foam in tubes containing the following:
- A gap inside the tube measuring 1/4 inch or greater (for both J-Lead and QFP devices in carriers)
- Plastic J-Lead Chip Carrier (PLCC) devices with 44 or more pins (full tubes containing PLCC devices with 28 or fewer pins generally do not require foam)
- Ceramic J-Lead Chip Carrier (JLCC) devices
The following figure shows the position of the stopper, foam, and devices in a tube.