Architecture
SAT is NP-complete and appears throughout AI planning, drug discovery, scheduling, and chip design automation. MEDUSA uses oscillator-based analog dynamics to find solutions in microseconds rather than the milliseconds typical of digital solvers. Two mixed-signal compute tiles, each with 200 oscillator-based spin cells and 508 programmable clause cells, connect to a RISC-V digital supervisor. Each tile accepts arbitrary k-SAT instances directly, with no preprocessing or connectivity restrictions.
Operation
Each Boolean variable maps to a gated relaxation oscillator. Make/Break feedback injects current to nudge oscillators toward satisfying assignments: when a clause is unsatisfied, current pushes the relevant spins toward a fix; when a clause becomes critically satisfied, the satisfying variable locks in place. The asymmetry lets the system keep exploring the solution space while it converges. Digital inter-macro coupling supports tiling for larger problems.
Results
On 1000 runs of 100-variable, 430-clause problems: 14.92 µs mean time to solution, 19.1 nJ mean energy to solution. 2.59 mm² total area (1.29 mm² per tile).