WEDPN16M64V-XB3X
128MB – 16Mx64 Synchronous DRAM
FEATURES
High Frequency = 100, 125, 133MHz
Package:
• 219 Plastic Ball Grid Array (PBGA), 21 x 21mm
Single 3.3V power supply
Fully Synchronous; all signals registered on positive edge
of system clock cycle
Internal pipelined operation; column address can be
changed every clock cycle
Internal banks for hiding row access/precharge
Programmable Burst length 1,2,4,8 or full page
8,192 refresh cycles
Commercial, Industrial and Military Temperature Ranges
Organized as 16M x 64
• User configurable as 2 x 16M x 32 and 4 x 16M x 16
Weight: WEDPN16M64V-XB3X - 2.0 grams typical
GENERAL DESCRIPTION
The 128MByte (1Gb) SDRAM is a high-speed CMOS, dynamic
random-access, memory using 4 chips containing 268,435,456
bits. Each chip is internally con
fi
gured as a quad-bank DRAM with
a synchronous interface. Each of the chip’s 67,108,864-bit banks
is organized as 8,192 rows by 512 columns by 16 bits.
Read and write accesses to the SDRAM are burst oriented;
accesses start at a selected location and continue for a programmed
number of locations in a programmed sequence. Accesses begin
with the registration of an ACTIVE command, which is then followed
by a READ or WRITE command. The address bits registered
coincident with the ACTIVE command are used to select the bank
and row to be accessed (BA0, BA1 select the bank; A0-12 select
the row). The address bits registered coincident with the READ or
WRITE command are used to select the starting column location
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 1Gb SDRAM uses an internal pipelined architecture to achieve
high-speed operation. This architecture is compatible 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
seamless, high-speed, random-access operation.
The 1Gb 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.
All inputs and outputs are LVTTL compatible. SDRAMs offer
substantial advances in DRAM operating performance, including
the ability to synchronously burst data at a high data rate with
automatic column-address generation, the ability to interleave
between internal banks in order to hide precharge time and the
continued on page 4
BENEFITS
58% SPACE SAVINGS
Reduced part count
Reduced trace lengths for lower parasitic capacitance
Suitable for hi-reliability applications
Laminate interposer for optimum TCE match
Upgradeable to 32M x 64 density (W332M64V-XBX)
* This product is subject to change without notice.
DENSITY COMPARISONS
Discrete Approach (mm)
11.9
11.9
11.9
11.9
WEDPN16M64V-XB3X
21
22.3
WEDPN16M64V-XB3X
21
S
A
V
I
N
G
S
58%
Area
4 x 265mm
2
= 1,060mm
2
441mm
2
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WEDPN16M64V-XB3X
FIGURE 1 – PIN CONFIGURATION
TOP VIEW
CAS
0
#
CS
0
#
WE
0
#
RAS
0
#
RAS
1
#
CAS
1
#
WE
1
#
CS
1
#
CS
3
#
CAS
3
# RAS
3
#
WE
3
#
RAS
2
#
WE
2
#
CS
2
#
CAS
2
#
NOTE:
DNU = Do Not Use; to be left unconnected for future upgrades.
NC = Not Connected Internally.
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December 2015
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WEDPN16M64V-XB3X
FIGURE 2 – FUNCTIONAL BLOCK DIAGRAM
WE0#
RAS0#
CAS0#
WE# RAS# CAS#
A0-12
DQ0
•
BA0-1
•
CLK
•
U0
CKE
•
•
CS#
•
DQML
DQ15
DQMH
A0-12
BA0-1
CLK0
CKE0
CS0#
DQML0
DQMH0
DQ0
•
•
•
•
•
•
DQ15
WE1#
RAS1#
CAS1#
CLK1
CKE1
CS1#
DQML1
DQMH1
WE# RAS# CAS#
A0-12
DQ0
•
BA0-1
•
CLK
•
U1
CKE
•
•
CS#
•
DQML
DQ15
DQMH
DQ16
•
•
•
•
•
•
DQ31
WE2#
RAS2#
CAS2#
CLK2
CKE2
CS2#
DQML2
DQMH2
WE# RAS# CAS#
A0-12
DQ0
•
BA0-1
•
CLK
•
U2
CKE
•
CS#
•
•
DQML
DQ15
DQMH
DQ32
•
•
•
•
•
•
DQ47
WE3#
RAS3#
CAS3#
CLK3
CKE3
CS3#
DQML3
DQMH3
WE# RAS# CAS#
A0-12
DQ0
•
BA0-1
•
CLK
•
U3
CKE
•
•
CS#
•
DQML
DQ15
DQMH
DQ48
•
•
•
•
•
•
DQ63
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December 2015
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WEDPN16M64V-XB3X
capability to randomly change column addresses on each clock
cycle during a burst access.
FUNCTIONAL DESCRIPTION
Read and write accesses to the SDRAM are burst oriented;
ac cess es start at a selected location and continue for a
programmed number of locations in a programmed sequence.
Accesses begin with the registration of an ACTIVE command which
is then followed by a READ or WRITE command. The address
bits registered coincident with the ACTIVE command are used to
select the bank and row to be accessed (BA0 and BA1 select the
bank, A0-12 select the row). The address bits (A0-8) registered
coincident with the READ or WRITE command are used to select
the starting column location for the burst access.
Prior to normal operation, the SDRAM must be initialized. The
following sections provide detailed information covering device
initialization, register definition, command descriptions and device
operation.
The Mode Register must be loaded when all banks are idle, and
the controller must wait the specified time before initiating the
subsequent operation. Violating either of these requirements will
result in unspeci
fi
ed operation.
BURST LENGTH
Read and write accesses to the SDRAM are burst oriented, with
the burst length being programmable, as shown in Figure 3. The
burst length determines the maximum number of column locations
FIGURE 3 – MODE REGISTER DEFINITION
A
12
A
11
A
10
A
9
A
8
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
Address Bus
12 11 10 9 8
Reserved*
7
6 5
4 3
BT
2 1
0
Mode Register (Mx)
WB Op Mode
CAS Latency
Burst Length
INITIALIZATION
SDRAMs must be powered up and initialized in a predefined
manner. Operational procedures other than those speci
fi
ed may
result in unde
fi
ned operation. Once power is applied and the clock
is stable (stable clock is defined as a signal cycling within timing
constraints specified for the clock pin), the SDRAM requires a
100μs delay prior to issuing any command other than a COMMAND
INHIBIT or a NOP. Starting at some point during this 100μs period
and continuing at least through the end of this period, COMMAND
INHIBIT or NOP commands should be applied.
Once the 100μs delay has been satisfied with at least one
COMMAND INHIBIT or NOP command having been applied, a
PRECHARGE command should be applied. All banks must be
precharged, thereby placing the device in the all banks idle state.
Once in the idle state, two AUTO REFRESH cycles must be
performed. After the AUTO REFRESH cycles are complete, the
SDRAM is ready for Mode Register programming. Because the
Mode Register will power up in an unknown state, it should be
loaded prior to applying any operational command.
*Should program
M12, M11, M10 = 0, 0, 0
to ensure compatibility
with future devices.
Burst Length
M2 M1 M0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
M3 = 0
1
2
4
8
Reserved
Reserved
Reserved
Full Page
M3 = 1
1
2
4
8
Reserved
Reserved
Reserved
Reserved
M3
0
1
Burst Type
Sequential
Interleaved
M6 M5 M4
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
CAS Latency
Reserved
Reserved
2
3
Reserved
Reserved
Reserved
Reserved
REGISTER DEFINITION
MODE REGISTER
The Mode Register is used to define the specific mode of operation
of the SDRAM. This definition includes the selec-tion of a burst
length, a burst type, a CAS latency, an operating mode and a
write burst mode, as shown in Figure 3. The Mode Register is
programmed via the LOAD MODE REGISTER command and will
retain the stored information until it is programmed again or the
device loses power.
Mode register bits M0-M2 specify the burst length, M3 specifies
the type of burst (sequential or interleaved), M4-M6 specify the
CAS latency, M7 and M8 specify the operating mode, M9 speci
fi
es
the WRITE burst mode, and M10 and M11 are reserved for future
use. Address A12 (M12) is undefined but should be driven LOW
during loading of the mode register.
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M9
0
1
M8
0
-
M7
0
-
M6-M0
Defined
-
Operating Mode
Standard Operation
All other states reserved
Write Burst Mode
Programmed Burst Length
Single Location Access
that can be accessed for a given READ or WRITE command.
Burst lengths of 1, 2, 4 or 8 locations are available for both the
sequential and the interleaved burst types, and a full-page burst
is available for the sequential type. The full-page burst is used in
conjunction with the BURST TERMINATE command to generate
arbitrary burst lengths.
Reserved states should not be used, as unknown operation or
incompatibility with future versions may result.
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WEDPN16M64V-XB3X
When a READ or WRITE command is issued, a block of columns
equal to the burst length is effectively selected. All accesses for
that burst take place within this block, meaning that the burst will
wrap within the block if a boundary is reached. The block is uniquely
selected by A1-8 when the burst length is set to two; by A2-8 when
the burst length is set to four; and by A3-8 when the burst length
is set to eight. The remaining (least significant) address bit(s) is
(are) used to select the starting location within the block. Full-page
bursts wrap within the page if the boundary is reached.
piece of output data. The latency can be set to two or three clocks.
If a READ command is registered at clock edge n, and the latency
is m clocks, the data will be available by clock edge n+m. The I/
Os will start driving as a result of the clock edge one cycle earlier
(n + m - 1), and provided that the relevant access times are met,
the data will be valid by clock edge n + m. For example, assuming
that the clock cycle time is such that all relevant access times are
met, if a READ command is registered at T0 and the latency is
programmed to two clocks, the I/Os will start driving after T1 and the
data will be valid by T2. Table 2 indicates the operating frequencies
at which each CAS latency setting can be used.
Reserved states should not be used as unknown operation or
incompatibility with future versions may result.
BURST TYPE
Accesses within a given burst may be programmed to be either
sequential or interleaved; this is referred to as the burst type and
is selected via bit M3.
The ordering of accesses within a burst is determined by the burst
length, the burst type and the starting column address, as shown
in Table 1.
OPERATING MODE
The normal operating mode is selected by setting M7and M8 to
zero; the other combinations of values for M7 and M8 are reserved
for future use and/or test modes. The programmed burst length
applies to both READ and WRITE bursts.
Test modes and reserved states should not be used because
unknown operation or incompatibility with future versions may
result.
TABLE 1 – BURST DEFINITION
Burst
Length
2
A1
0
0
1
1
A2
A1
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
n = A0-9/8/7
(location 0-y)
Starting Column
Address
A0
0
1
A0
0
1
0
1
A0
0
1
0
1
0
1
0
1
Order of Accesses Within a Burst
Type = Sequential
Type = Interleaved
0-1
1-0
0-1-2-3
1-2-3-0
2-3-0-1
3-0-1-2
0-1-2-3-4-5-6-7
1-2-3-4-5-6-7-0
2-3-4-5-6-7-0-1
3-4-5-6-7-0-1-2
4-5-6-7-0-1-2-3
5-6-7-0-1-2-3-4
6-7-0-1-2-3-4-5
7-0-1-2-3-4-5-6
Cn, Cn + 1, Cn + 2
Cn + 3, Cn + 4...
…Cn - 1, Cn…
0-1
1-0
0-1-2-3
1-0-3-2
2-3-0-1
3-2-1-0
0-1-2-3-4-5-6-7
1-0-3-2-5-4-7-6
2-3-0-1-6-7-4-5
3-2-1-0-7-6-5-4
4-5-6-7-0-1-2-3
5-4-7-6-1-0-3-2
6-7-4-5-2-3-0-1
7-6-5-4-3-2-1-0
Not Supported
TABLE 2 - CAS LATENCY
ALLOWABLE OPERATING
FREQUENCY (MHz)
SPEED
-100
-125
-133
4
CAS LATENCY = 2
-75
-100
-100
CAS LATENCY = 3
-100
-125
-133
8
WRITE BURST MODE
When M9 = 0, the burst length programmed via M0-M2 applies
to both READ and WRITE bursts; when M9 = 1, the programmed
burst length applies to READ bursts, but write accesses are single-
location (nonburst) accesses.
Full
Page (y)
COMMANDS
The Truth Table provides a quick reference of available commands.
This is followed by a written description of each command. Three
additional Truth Tables appear following the Operation section;
these tables provide current state/next state information.
NOTES:
1. For full-page accesses: y = 512.
2. For a burst length of two, A1-8 select the block-of-two burst; A0 selects the starting column
within the block.
3. For a burst length of four, A2-8 select the block-of-four burst; A0-1 select the starting column
within the block.
4. For a burst length of eight, A3-8 select the block-of-eight burst; A0-2 select the starting column
within the block.
5. For a full-page burst, the full row is selected and A0-8 select the starting column.
6. Whenever a boundary of the block is reached within a given sequence above, the following
access wraps within the block.
7. For a burst length of one, A0-8 select the unique column to be accessed, and Mode Register bit
M3 is ignored.
COMMAND INHIBIT
The COMMAND INHIBIT function prevents new commands from
being executed by the SDRAM, regardless of whether the CLK
signal is enabled. The SDRAM is effectively deselected. Operations
already in progress are not affected.
CAS LATENCY
The CAS latency is the delay, in clock cycles, between the
registration of a READ command and the availability of the
fi
rst
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NO OPERATION (NOP)
The NO OPERATION (NOP) command is used to perform a NOP
to an SDRAM which is selected (CS# is LOW). This prevents
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