Wataru Wakamiya

A 34-ns 16-Mb DRAM with controllable voltage down-converter

A high-speed 16-Mb DRAM with high reliability is reported. A multidivided column address decoding scheme and a fully embedded sense-amplifier driving scheme were used to meet the requirements for high speed. A low-power hybrid internal power supply voltage converter with an accelerated life-test function is also proposed and was demonstrated. A novel substrate engineering technology, a retrograded well structure formed by a megaelectronvolt ion-implantation process, provides a simple process sequence and high reliability in terms of soft error and latch-up immunity. >

A 60-ns 3.3-V-only 16-Mbit DRAM with multipurpose register

A single 3.3-V 16-Mbit DRAM with a 135-mm/sup 2/ chip size has been fabricated using a 0.5- mu m twin-well process with double-metal wiring. The array architecture, based on the twisted-bit-line (TBL) array, includes suitable dummy and space word-line configurations which suppress the inter-bit-line noise and bring yield improvement. The multipurpose register (MPR) designed for the hierarchical data bus structure provides a line-mode test (LMT), copy write, and cache access capability. The LMT with on-chip test circuits using the MPR and a comparator creates a random test pattern and reduces the test time to 1/1000. A field shield isolation and a T-shaped stacked capacitor allow the layout of a 4.8- mu m/sup 2/ cell size with a storage capacitance of 35 fF. These techniques enable the 3.3-V 16-Mbit DRAM to achieve a 60-ns RAS access time and 300-mW power dissipation at 120-ns cycle time. >

A 60 ns 3.3 V 16 Mb DRAM

The authors describe a single 3.3-V, 16-Mb DRAM (dynamic RAM) fabricated in a 0.5- mu m, twin-well CMOS technology and packaged in a 400-mil small-outline J-leaded package. The design features are an array architecture based on the twisted-bit-line (TBL) technique and a multipurpose register (MPR) enabling an effective line mode test (LMT), copy write, and high-speed cache access capability. Under typical conditions at V/sub cc/=3.3 V, a row-address-strobe access time of 60 ns was obtained. Features of the RAM are summarized.<<ETX>>