Dual-ended or Single-ended read

1. Dual ended when read/write ports are shared (6T cell)

2. Dual ended when you want to read fast; use a diff-sense-amp to sense a very small voltage difference.

Vias

rectangular vias better than square vias - why?

except in the case of - small interconnects (wires) (eg: M1) since rectangular vias have bigger side-wall caps. This would dominate the small wire capacitance.

Golden rule of thumb for small wires: close to driver - rectangular & close to load - square