The pad list is finished and counted; now each pad needs a ball, and the balls need an order the board can actually route. The package is the middle of that sandwich, and its choice constrains everything: how many balls exist, how much inductance each supply path carries, and how the board escapes the array. This topic chooses the package at the concept level, assigns the 31 balls by rule on a 6 x 6 array, and runs the review that catches the classic mismatch between the chip's map and the board's netlist.
Lesson | After it you can... |
|---|---|
Choose a package family for NanoSoC and state what the choice costs. | |
Assign every NanoSoC pad to a ball and check the assignment by script. | |
Pass a pinout review with the board team and catch a ball that moved on one side only. |
Suggested order: top to bottom. The package first, because its ball count and inductance bound the assignment; then the assignment; then the review that proves the board can live with it. The power-delivery topic next door prices the supply paths this topic draws.
Because only the integrator sees both sides: which pad needs a quiet neighbour, which supply needs a short path, and which ball the board can route. The vendor draws what it is told; the integrator decides what to tell it.