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Hiroyuki KOHNO Yasuyuki NAKAMURA Takahiro MIKI Hiroyuki AMISHIRO Keisuke OKADA Tadashi SUMI
High-end graphic systems with 3 million pixels require 8-bit D/A converters with more than 300-MS/s conversion rate. Furthermore, D/A converters need to operate with low supply voltage when they are integrated with large-scale digital circuits on a harf-micron CMOS process. This paper describes a 350-MS/s 8-bit CMOS D/A converter with 3.3-V power supply. A current source circuit with a delayed driving scheme is developed. This driving scheme reduces a fluctuation of internal node voltage of the current source circuit and high-speed swiching is realized. In addition to this driving scheme, two stages of latches are inserted into matrix decoder for reducing glitch energy and for enhancing decoding speed. The D/A converter is fabricated in a 0.5-µm CMOS process with single poly-silicon layer and double aluminum layers. Its settling time is less than 2.4 ns and it successfully operates at 350 MS/s.