A 1.3-GHz fifth-generation SPARC64 microprocessor

A fifth-generation SPARC64 processor is fabricated in 130-nm partially depleted silicon-on-insulator CMOS with eight layers of Cu metallization. At V-dd = 1.2 V and T-alpha = 25degreesC, it runs at 1.3 GHz and dissipates 34.7 W. The chip contains 191 M transistors with 19 M logic circuits in an area of 18.14 mm x 15.99 mm and is covered with 5858 bumps, of which 269 are for I/O signals. It is mounted in a 1360-pin land-grid-array package. The 16-byte-wide system bus operates with a 260-MHz clock in single-data-rate or double-data-rate modes. This processor implements an error-detection mechanism for execution units and data path logic circuits in addition to on-chip arrays to detect data corruption. Intermittent errors detected in execution units and data paths are recovered via instruction retry. A soft barrier clocking scheme allows amortization of the clock skew and jitter over multiple cycles and helps to achieve high clock frequency. Tunability of the clock timing makes timing closure easier. A relatively small amount of custom circuit design and the use of mostly static circuits contributes to achieve short development time.