Today at the IEEE International Electron Devices Meeting in San Francisco, IBM [ieee.org] reported a new 8-bit analog chip. But the true development was less about analog chips catching up to their digital peers and more a radical rethink of chip architecture: this chip is the first to perform 8-bit calculations right where information is stored.
In traditional von Neumann chip architecture, data constantly shuttles between memory and processing, which consumes valuable energy and time. IBM’s new analog chip is based on phase-change memory. The key ingredient is a material that can undergo phase changes in response to electrical current. Typically, these are alloys of germanium, tellurium, and antimony. In one phase, which is conductive, the atoms are lined up nicely. In the other phase, which doesn’t conduct electricity, the atoms move around, heated locally by current, and become jumbled.