IPC-782
Three-Tiers
IPC-782
specification specifies three-tiers to accomodate products having different
requirements for reliability, maintainability and board density.
Here's
a description of each of the three different tiers and when you should use them:
- Most
is for boards that are subjected to high shock/vibration or are involved
in life support such as automotive, aerospace, medical applications. These
boards need to be easily reworked. Performance Class 3 High Reliability
Electronic Products.
- Nominal
is for boards that are in devices that require only average dependability
such as consumer applications, computers, appliances and home entertainment
systems. The pad and courtyard sizes are average. Performance Class 2 Dedicated
Service Electronic Products.
- Least
is for boards that are thrown away if they break or need service such as
Palm Pilots, cell phones, toys, PCMCIA boards or very dense boards. Performance
Class 1 General Electronic Products.