A String-in-string-out 256 Bits eFuse Using Full-custom Design in 55nm Process

Electrically programmable fuse (eFuse) is a one-time programmable memory and compatible with CMOS process. eFuse permanently store the key information and adopts parallel structure in large-scale integrated circuits. However, this structure causes area problem with decoder circuit. Therefore, this paper proposes an eFuse scheme without decoder to save area. This work adopts the full customization method and the idea of series connection to design an eFuse circuit with serial data input and serial output. This article finished under 55nm craft, test the stability of its read-write function. In the programming mode, the programming current reaches more than 15mA, which theoretically shows that the fuse is blown. In the reading mode, the reading current is less than 50uA, the leakage current is less than 2uA, the influence on the electric fuse is negligible. The stability meets the requirements.