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extended data output DRAM (EDO-DRAM)

Extended Data Output (EDO) is a technique developed in 1994 to accelerate the access speed ofmain memories. This technique shortens the read cycle by internally already processing the following address

for access, while at the outputs the read data is delayed by minimal time periods. This parallel processing increases the access speed. The data read time for the four Q-words is 9 clocks in the burst cycle 5-2-2. The EDO technique, which operates asynchronously and does not require a clock signal, is used with RAMs and DRAMs. EDO-capable motherboards

are a prerequisite; other motherboards do not support the functions of the EDO modules. Access times

aresaid to improve by 20% or more with EDO technology

.

Thus, with an EDO DRAM the data transfer rates are between 50 ns and 70 ns and the clock frequencies between 33 MHz and 75 MHz. Such a memory device operates with supply voltages between 3.3 V (3V3) and 5.0 V (5V) and has 72 pins

.

64 MB EDO DRAM as SIMM module, photo: leugimnet.galeon.com

64 MB EDO DRAM as SIMM module, photo: leugimnet.galeon.com

EDO, also known as Hyper Page Mode (HPM), has replaced the older Fast Page Mode (FPM). In the mid-1990s, the transition from EDO DRAM to the faster Synchronous Dynamic RAMs (SDRAM) takes place.

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Englisch: extended data output DRAM - EDO-DRAM
Updated at: 23.12.2011
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Translations: DE