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SDRAM
High-Performance Memory |
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SDRAM (Synchronous DRAM) is the common term to classify PC66 (1997), PC100
(1998) and PC133 SDRAM (1999/2000). SDRAMs are based on standard dynamic RAM
chips, but have sophisticated features that make them considerably faster.
First, SDRAM chips are fast enough to be synchronized with the CPU's clock,
which eliminates wait states. Second, the SDRAM chip is divided into two cell
blocks, and data is interleaved between the two so that while a bit in one
block is being accessed, the bit in the other is being prepared for access.
This allows SDRAM to burst the second and subsequent, data bits at a rate
of 10ns, compared to 60ns for the first character. SDRAM chips use a power
supply voltage of 3.3 volts.
- Scalability of Speeds to Reach 133 Mhz.
- Available in both Unbuffered and ECC Registered Versions
- Available in 168 DIMM and 144 pin So-DIMM Form Factors
- 3.3 Volt Operating Voltage
- High density: Up to 2GB
- Ideal for Legacy Designs and Embedded Systems Designs that use simpler
DRAM Controllers
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There are two standard speeds for SDRAM products: PC-100 and PC-133.
PC-100 modules operate at a 100Mhz clock frequency and achieve a peak bandwidth
of 800MB/s.
PC-133 modules operate at a 133 Mhz clock frequency and achieve a peak bandwidth
of 1066MB/s.
SDRAM chips use a clock which is synchronized with the CPU's clock. The SDRAM
chip is divided into two cell blocks and data is interleaved between the two
so that while a bit in one block is being accede, the bit in the other is being
prepared for access. This allows the SDRAM to burst the second and subsequent
characters at a rate of 10 nsec. (PC-100) or 7.5 nsec. (PC-133).
| WILL SDRAM WORK ON MY SYSTEM? |
SDRAM is an older interface technology that has been superseded by DDR,
DDR2, or DDR3 in many applications. It may still be the right choice
for designs using older microprocessors or chipsets that were designed
several years ago. It may also be the right choice for use as an upgrade
for systems that have already been installed in the field. You should
refer to your system or microprocessor documentation to see if it does
use the SDRAM interface. SDRAM modules will not work in DDR or DDR2 sockets
or vice-versa so it is important to use exactly the type of module that
was originally intended for your application.
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