Direct RDRAM
™
Page 1
K4R271669B/K4R441869B
Version 1.11 Oct. 2000
Overview
The Rambus Direct RDRAM™ is a general purpose highperformance 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 128/144-Mbit Direct Rambus DRAMs (RDRAM) are
extremely high-speed CMOS DRAMs organized as 8M
words by 16 or 18 bits. The use of Rambus Signaling Level
(RSL) technology 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 organization are general and can be used for additional storage and
bandwidth or for error correction.
Features
♦ 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 simultaneously at full bandwidth data rates
♦ Low latency features
- Write buffer to reduce read latency
- 3 precharge mechanisms for controller flexibility
- Interleaved transactions
♦ Advanced power management:
- Direct RDRAM operates from a 2.5 volt supply
- Multiple low power states allows flexibility in power
consumption versus time to transition to active state
- Power-down self-refresh
♦ Organization: 1Kbyte pages and 32 banks, x 16/18
- x18 organization allows ECC configurations or
increased storage/bandwidth
- x16 organization for low cost applications
♦ Uses Rambus Signaling Level (RSL) for up to 800MHz
operation
The 128/144-Mbit Direct RDRAMs are offered in a CSP
horizontal package suitable for desktop as well as lowprofile add-in card and mobile applications.
Key Timing Parameters/Part Numbers
a.“32s” - 32 banks which use a “split” bank architecture.
b.“N” - normal package, “M” - mirrored package.
c.“C” - RDRAM core uses normal power self refresh.
Figure 1: Direct RDRAM CSP Package
Organization
Speed
Part Number
Bin
I/O
Freq.
MHz
t
RAC
(Row
Access
Time) ns
256Kx16x32sa-CK8 800 45
K4R271669B-Nb(M)CcK8
-CK7 711 45
K4R271669B-N(M)CK7
-CG6 600 53.3
K4R271669B-N(M)CG6
256Kx18x32sa-CK8 800 45
K4R441869B-N(M)CK8
-CK7 711 45
K4R441869B-N(M)CK7
-CG6 600 53.3
K4R441869B-N(M)CG6
a. Normal Package b. Mirrored Package
K4Rxxxx69B-Nxxx
SAMSUNG 050
M
K4Rxxxx69B-Mxxx
SAMSUNG 050