# sch-rnd - use cases

## The Packaging problem

### Setup

- sch -> pcb flow
- generic (light) symbol in the schematics (e.g. a generic IC)
- footprint attribute set to a generic package (e.g. a generic BGA256)

### Problems

- the pin numbering of the IC is arbitrary
- the pin numbering of the Package is arbitrary
- a Package+IC doesn't determine the pinout: there are various IC devices with different pinouts with the same footprint
- number of logical pins may not match number of physical pins; unused pins, multiple pins connected, power and ground rings,passive componnents
- Package designers will also use cschem to design the package
- IC designers will also use cschem to design the bonding diagram