Method and circuit for scalable cross point switching using 3-D die stacking

A cross-point switch having stacked switching dies on a component die is disclosed. The cross point switch allows scalability by adding switching dies. The switching dies include ingress switches that are coupled to multiplexers to a middle stage switches. The inputs and outputs of the ingress switches are connected to the switching interface region via through silicon vias (TSVs). The outputs of the ingress switches are also coupled by TSVs to multiplexers for routing to middle stage switches on a switching die above. If the switching die is stacked on another switching die, the outputs of the ingress switches are coupled by TSVs to the multiplexers for routing to the middle stage switches of the switching die below. By adding switching dies, the switch is configurable to increase the number of ports as well as the width of the ports.