WEDPN4M64V-XBX
4Mx64 Synchronous DRAM
FEATURES
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High Frequency = 100, 125MHz
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Package:
鈥?219 Plastic Ball Grid Array (PBGA), 21 x 21mm
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Single 3.3V 鹵0.3V power supply
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Fully Synchronous; all signals registered on positive edge
of system clock cycle
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Internal pipelined operation; column address can be
changed every clock cycle
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Internal banks for hiding row access/precharge
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Programmable Burst length 1,2,4,8 or full page
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4096 refresh cycles
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Commercial, Industrial and Military Temperature Ranges
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Organized as 4M x 64
鈥?User Configurable as 2 x 4M x 32 or 4 x 4M x 16
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Weight: WEDPN4M64V-XBX - 2 grams typical
GENERAL DESCRIPTION
The 32MByte (256Mb) SDRAM is a high-speed CMOS, dy-
namic random-access ,memory using 4 chips containing
67,108,864 bits. Each chip is internally configured as a quad-
bank DRAM with a synchronous interface. Each of the chip鈥檚
16,777,216-bit banks is organized as 4,096 rows by 256
columns by 16 bits.
Read and write accesses to the SDRAM are burst oriented;
accesses start at a selected location and continue for a pro-
grammed number of locations in a programmed sequence.
Accesses begin with the registration of an ACTIVE com-
mand, which is then followed by a READ or WRITE com-
mand. The address bits registered coincident with the AC-
TIVE command are used to select the bank and row to be
accessed (BA0, BA1 select the bank; A0-11 select the row).
The address bits registered coincident with the READ or
WRITE command are used to select the starting column lo-
cation for the burst access.
The SDRAM provides for programmable READ or WRITE burst
lengths of 1, 2, 4 or 8 locations, or the full page, with a
burst terminate option. An AUTO PRECHARGE function may
be enabled to provide a self-timed row precharge that is
initiated at the end of the burst sequence.
The 256Mb SDRAM uses an internal pipelined architecture
to achieve high-speed operation. This architecture is com-
patible with the 2n rule of prefetch architectures, but it also
allows the column address to be changed on every clock
cycle to achieve a high-speed, fully random access.
Precharging one bank while accessing one of the other three
banks will hide the precharge cycles and provide seam-
less, high-speed, random-access operation.
The 256Mb SDRAM is designed to operate in 3.3V, low-
power memory systems. An auto refresh mode is provided,
along with a power-saving, power-down mode.
BENEFITS
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58% SPACE SAVINGS
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Reduced part count
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Low Profile: 2.20 mm (0.087) Max
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Reduced trace lengths for lower parasitic capacitance
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Laminate interposer for optimum TCE match
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Suitable for hi-reliability applications
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Upgradeable to 8M x 64 (contact factory for availability)
*This product is subject to change without notice.
11.9
Discrete Approach
ACTUAL SIZE
21
WEDPN4M64V-XBX
22.3
54
TSOP
54
TSOP
54
TSOP
54
TSOP
21
S
A
V
I
N
G
S
58%
Area
4 x 265mm
2
= 1061mm
2
441mm
2
November 2003 Rev. 7
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White Electronic Designs Corporation 鈥?(602) 437-1520 鈥?www.whiteedc.com
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