Sophon PFG-1: a monolithic-3D AI ASIC with 330 GB on-die DRAM and no HBM
Summary
PhantaField's Sophon PFG-1 whitepaper describes a monolithic-3D AI accelerator with 330 GB on-die 2T0C DRAM and pure digital CIM. It claims 4,200 TFLOPS FP8 and 2,100 TFLOPS BF16 on-die, a 0.620 pJ per BF16 forward MAC and 0.310 pJ per FP8 MAC, and a refresh power of ~0.08 W at 1 Hz, enabled by 1 fA/µm off-current. The paper argues this architecture eliminates off-die HBM, details scaling roadmap to 2034, and compares economics and energy against NVIDIA Rubin and AMD Instinct MI455X.