Memory devices are used to store information in various processing systems, such as computer systems, handheld devices, and other electronic devices or systems. The stored information is retrieved by microprocessors or microcontrollers to perform various tasks in the systems. With improved technology, the operating speeds of microprocessors and microcontrollers have increased dramatically, which has increased demand for faster and larger memory subsystems.
Memory devices are typically coupled to a memory bus. Traditionally, memory devices are coupled to the memory bus in a multi-drop arrangement, in which a group of signal lines (making up the memory bus) is connected to multiple memory devices at multiple points. Each connection point of a memory device(s) to the memory bus is referred to as a drop. Multiple connections thus correspond to multiple drops. Memory capacity can be added by adding more “drops”—that is, additional connection points of memory device(s) to the memory bus.
However, as more memory devices are added to a multi-drop memory bus, capacitive loading is increased that may slow down memory device operation. Also, the peak data rate on a multi-drop memory bus is reduced due to impedance mismatches associated with discontinuities on the multi-drop memory bus. Multi-drop memory buses also have other electrical characteristics that reduce memory bus performance.