1. Chip size. You need to know what kinds of package will be used. # m; y: x5 c. i" C# |* W2. Pad location. You need to confirm with supplier about the bond wire bonding.7 c7 K" r2 E$ Z: [+ s
3. ESD and latchup consideration. * R, \3 A+ B" x: d4 k2 ]0 y- b4. Any noisy circuit inside the circuit. If yes, you may need to isolate those noisy circuits with double guard ring or individual ground and power path.6 H* I* n9 S# ~* w$ K4 r
5. The current consumption on the whole circuit. It will affect the metal width of each building block and the whole circuit.1 L! w% C# c+ y. w) z! u& V
6. Make sure there is no softcon connection.& Z0 z7 x$ n$ }; ]6 r- G
7. How many metal layers could be used ?. N3 |' R1 F' ~6 N& u$ o8 t
8. Metal Density consideration.