DocumentCode
1545278
Title
A 126.6-mm2 AND-type 512-Mb flash memory with 1.8-V power supply
Author
Ishii, Tatsuya ; Oshima, Kazuyoshi ; Sato, Hiroshi ; Noda, Satoshi ; Kishimoto, Jiro ; Kotani, Hiroaki ; Nozoe, Atsushi ; Furusawa, Kazunori ; Yoshitake, Takayuki ; Kato, Masataka ; Takahashi, Masahito ; Sato, Akihiko ; Kubono, Shoji ; Manita, Kiichi ; Ko
Author_Institution
Device Dev. Center, Hitachi Ltd., Tokyo, Japan
Volume
36
Issue
11
fYear
2001
fDate
11/1/2001 12:00:00 AM
Firstpage
1707
Lastpage
1712
Abstract
A 512-Mb flash memory, which is applicable to removable flash media of portable equipment such as audio players, has been developed. The chip is fabricated with a 0.18-μm CMOS process on a 126.6-mm2 die, and uses a multilevel technique (2 bit/1 cell). The memory cell is AND-type, which is suitable for multilevel operation. This paper reports new techniques adopted in the 512-Mb flash memory. First, techniques for low voltage operation are described. The charge pump, control of pumps, and the reference voltage generator are improved to generate internal voltage stably for multilevel flash memory. Next, a method for reducing total memory cost in the removable flash media is described. A new operation mode named read-modify-write is introduced on the chip. This feature makes the memory system simple, because the controller does not have to track sector-erase information
Keywords
CMOS memory circuits; flash memories; low-power electronics; 1.8 V; 126.6 mm; 512 Mbit; AND-type flash memory; CMOS process; audio players; charge pump; control of pumps; low voltage operation; multilevel technique; portable equipment; read-modify-write mode; reduced total memory cost; reference voltage generator; removable flash media; stable internal voltage generation; CMOS process; Capacitors; Charge pumps; Circuits; Costs; Flash memory; Low voltage; Parasitic capacitance; Portable media players; Power supplies;
fLanguage
English
Journal_Title
Solid-State Circuits, IEEE Journal of
Publisher
ieee
ISSN
0018-9200
Type
jour
DOI
10.1109/4.962292
Filename
962292
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