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Naoya WATANABE Fukashi MORISHITA Yasuhiko TAITO Akira YAMAZAKI Tetsushi TANIZAKI Katsumi DOSAKA Yoshikazu MOROOKA Futoshi IGAUE Katsuya FURUE Yoshihiro NAGURA Tatsunori KOMOIKE Toshinori MORIHARA Atsushi HACHISUKA Kazutami ARIMOTO Hideyuki OZAKI
This paper describes an Embedded DRAM Hybrid Macro, which supports various memory specifications. The eDRAM module generator with Hybrid Macro provides more than 120,000 eDRAM configurations. This eDRAM includes a new architecture called Auto Signal Management (ASM) architecture, which automatically adjusts the timing of the control signals for various eDRAM configurations, and reduces the design Turn Around Time. An Enhanced-on-chip Tester performs the maximum 512b I/O pass/fail simultaneous judgments and the real time repair analysis. The eDRAM testing time is reduced to about 1/64 of the time required using the conventional technique. A test chip is fabricated using a 0.18 µm 4-metal embedded DRAM technology, which utilizes the triple-well, dual-Tox, and Co salicide process technologies. This chip achieves a wide voltage range operation of 1.2 V at 100 MHz to 1.8 V at 200 MHz.
Katsumi DOSAKA Akira YAMAZAKI Naoya WATANABE Hideaki ABE Jun OHTANI Toshiyuki OGAWA Kazunori ISHIHARA Masaki KUMANOYA
This paper describes a system integrated memory with direct interface to CPU which integrates an SRAM, a DRAM, and control circuitry, including a tag memory (TAG). This memory realizes a computer system without glue chips, and thus enables a computer system which is low cost, low power, and compact size, but still with sufficient performance. And fast clock cycle time and access time is realized using a newly proposed clock driver and internal signal generator. This memory is fabricated with a quad-polysilicon double-metal 0.55-µm CMOS process which is the same as used in a conventional 16-Mb DRAM. The chip size of 145.3mm2 is only a 12% increase over the conventional 16-Mb DRAM. The maximum operating frequency is 90-MHz and the operating current at cache-hit is 156-mA. This memory is suitable for various types of computer systems such as personal digital assistants(PDA's), personal computer systems, and embedded controller applications.
Takeshi FUJINO Akira YAMAZAKI Yasuhiko TAITO Mitsuya KINOSHITA Fukashi MORISHITA Teruhiko AMANO Masaru HARAGUCHI Makoto HATAKENAKA Atsushi AMO Atsushi HACHISUKA Kazutami ARIMOTO Hideyuki OZAKI
A low power 16 Mb embedded DRAM (eDRAM) macro is fabricated using 0.15 µm logic -based embedded DRAM process technology. A 0.5 µm2 CUB (
Hisashi IWAMOTO Naoya WATANABE Akira YAMAZAKI Seiji SAWADA Yasumitsu MURAI Yasuhiro KONISHI Hiroshi ITOH Masaki KUMANOYA
A multiple-registered architecture is described for 180 MHz 16 Mbit synchronous DRAM. The proposed architecture realizes a flexible control of critical timings such as I/O line busy time and achieves an operation at 180 MHz clock rate with area penalty of only 5.4% over the conventional DRAM.
Masaru HARAGUCHI Tokuya OSAWA Akira YAMAZAKI Chikayoshi MORISHIMA Toshinori MORIHARA Yoshikazu MOROOKA Yoshihiro OKUNO Kazutami ARIMOTO
This paper describes new DDRx SDRAM interface architecture suitable for system-on-chip (SOC) implementation. Our test chip fabricated in a 90-nm CMOS process adopts three key schemes and achieves 960 Mb/s/pin operations with 32 bits width. One of new schemes is to suppress timing skew with rising-edge signal transmission I/O circuit and look-up table type impedance calibration circuit. DQS round-trip-time, propagation delay from rising edge of system clock in SOC to arrival of DQS at input PAD of SOC during read operation, becomes longer than one clock cycle time as for DDR2 interface and beyond. Flexible DQS round-trip-time scheme can allow wide range up to N/2 cycles in N bits burst read operation. In addition, full self loop-backed test scheme is also proposed to measure AC timing parameters without high-end tester. The architecture reported in this paper can be continuously adaptive to realize higher data-rate and cost-efficient DDRx-SDRAM interface for various kinds of SOC.
Akira YAMAZAKI Fukashi MORISHITA Naoya WATANABE Teruhiko AMANO Masaru HARAGUCHI Hideyuki NODA Atsushi HACHISUKA Katsumi DOSAKA Kazutami ARIMOTO Setsuo WAKE Hideyuki OZAKI Tsutomu YOSHIHARA
The voltage margin of an embedded DRAM's sense operation has been shrinking with the scaling of process technology. A method to estimate this margin would be a key to optimizing the memory array configuration and the size of the sense transistor. In this paper, the voltage margin of the sense operation is theoretically analyzed. The accuracy of the proposed voltage margin model was confirmed on a 0.13-µm eDRAM test chip, and the results of calculation were generally in agreement with the measured results.
Akira YAMAZAKI Takeshi FUJINO Kazunari INOUE Isamu HAYASHI Hideyuki NODA Naoya WATANABE Fukashi MORISHITA Katsumi DOSAKA Yoshikazu MOROOKA Shinya SOEDA Kazutami ARIMOTO Setsuo WAKE Kazuyasu FUJISHIMA Hideyuki OZAKI
A 23.3 mm2 32 Mb embedded DRAM (eDRAM) macro has been fabricated using 0.18 µm triple-well 4-metal embedded DRAM process technology to realize an accelerated 3-D graphics controller. The array architecture, using a dual-port sense amplifier, achieves the column access latency of two cycles at 222 MHz and a peak data rate of 14.2 4 GB/s at 4 macros. The process cost has been kept low by using VT-MOS circuit technology and taking advantage of a characteristic of dual-gate oxide process technology. A tRAC of 11.6 ns at 2.0 V is achieved using a 'pre-detect redundancy' circuit.
Akira YAMAZAKI Tadato YAMAGATA Yutaka ARITA Makoto TANIGUCHI Michihiro YAMADA
The features for the integration of 1Tr/1C DRAM and logic for graphic and multimedia applications are surveyed. The key circuit/process technology for large scale embedded DRAM cores is described. The methods to improve transistor performance and gate density are shown. Noise immunity design and easy customization techniques are also introduced.