Direct RDRAM™
256/288-Mbit (512Kx16/18x32s) Preliminary
Overview
The Rambus Direct RDRAM™ is a general purpose high-
performance memory device suitable for use in a broad
range of applications including computer memory, graphics,
video, and any other application where high bandwidth and
low latency are required.
The 256/288-Mbit Direct Rambus DRAMs (RDRAM)are
extremely high-speed CMOS DRAMs organized as 16M
words by 16 or 18 bits. The use of Rambus Signaling Level
www.DataSh(eReSt4LU).ctoemchnology permits 600MHz to 800MHz transfer
rates while using conventional system and board design
technologies. Direct RDRAM devices are capable of
sustained data transfers at 1.25 ns per two bytes (10ns per
sixteen bytes).
The architecture of the Direct RDRAMs allows the highest
sustained bandwidth for multiple, simultaneous randomly
addressed memory transactions. The separate control and
data buses with independent row and column control yield
over 95% bus efficiency. The Direct RDRAM's 32 banks
support up to four simultaneous transactions.
System oriented features for mobile, graphics and large
memory systems include power management, byte masking,
and x18 organization. The two data bits in the x18 organiza-
tion are general and can be used for additional storage and
bandwidth or for error correction.
Features
0 Highest sustained bandwidth per DRAM device
- 1.6GB/s sustained data transfer rate
- Separate control and data buses for maximized
efficiency
- Separate row and column control buses for
easy scheduling and highest performance
- 32 banks: four transactions can take place simul-
taneously at full bandwidth data rates
0 Low latency features
- Write buffer to reduce read latency
- 3 precharge mechanisms for controller flexibility
- Interleaved transactions
0 Advanced power management:
- Multiple low power states allows flexibility in power
consumption versus time to transition to active state
- Power-down self-refresh
0 Organization: 2Kbyte pages and 32 banks, x 16/18
- x18 organization allows ECC configurations or
increased storage/bandwidth
- x16 organization for low cost applications
0 Uses Rambus Signaling Level (RSL) for up to 800MHz
operation
Figure 1: Direct RDRAM uBGA Package
The 256/288-Mbit Direct RDRAMs are offered in a uBGA
package suitable for desktop as well as low-profile add-in
card and mobile applications.
Direct RDRAMs operate from a 2.5 volt supply.
Key Timing Parameters / Part Numbers
Organizationa
I/O Freq. Core Access Time
MHz
(ns)
512Kx16x32s
600
53
512Kx16x32s
512Kx16x32s
711
800
45
45
512Kx16x32s
512Kx18x32s
512Kx18x32s
512Kx18x32s
512Kx18x32s
800
600
711
800
800
40
53
45
45
40
Part
Number
HY5R256HC653
HY5R256HC745
HY5R256HC845
HY5R256HC840
HY5R288HC653
HY5R288HC745
HY5R288HC845
HY5R288HC840
a. The bank “32s” designation indicates that this RDRAM core is
composed of 32 banks which use a “split” bank architecture.
Rev. 0.9 / Dec.2000
1
This document is a general product description and is subject to change without notice. Hynix Semiconductor Inc. does not assume any responsibility for use of
circuits described. No patent licenses are implied.
