General Description
High-speed DDR4 SDRAM modules use DDR4 SDRAM devices with two or four internal
memory bank groups. DDR4 SDRAM modules utilizing 4- and 8-bit-wide DDR4 SDRAM
devices have four internal bank groups consisting of four memory banks each, provid-
ing a total of 16 banks. 16-bit-wide DDR4 SDRAM devices have two internal bank
groups consisting of four memory banks each, providing a total of eight banks. DDR4
SDRAM modules benefit from DDR4 SDRAM's use of an 8n-prefetch architecture with
an interface designed to transfer two data words per clock cycle at the I/O pins. A single
READ or WRITE operation for the DDR4 SDRAM effectively consists of a single 8n-bit-
wide, four-clock data transfer at the internal DRAM core and eight corresponding n-bit-
wide, one-half-clock-cycle data transfers at the I/O pins.
DDR4 modules use two sets of differential signals: DQS_t and DQS_c to capture data
and CK_t and CK_c to capture commands, addresses, and control signals. Differential
clocks and data strobes ensure exceptional noise immunity for these signals and pro-
vide precise crossing points to capture input signals.
Fly-By Topology
DDR4 modules use faster clock speeds than earlier DDR technologies, making signal
quality more important than ever. For improved signal quality, the clock, control, com-
mand, and address buses have been routed in a fly-by topology, where each clock, con-
trol, command, and address pin on each DRAM is connected to a single trace and ter-
minated (rather than a tree structure, where the termination is off the module near the
connector). Inherent to fly-by topology, the timing skew between the clock and DQS sig-
nals can be easily accounted for by using the write-leveling feature of DDR4.
Module Manufacturing Location
Micron Technology manufactures modules at sites world-wide. Customers may receive
modules from any of the following manufacturing locations:
Table 7: DRAM Module Manufacturing Locations
Manufacturing Site Location Country of Origin Specified on Label
Boise, USA USA
Aguadilla, Puerto Rico Puerto Rico
Xian, China China
Singapore Singapore
8GB (x64, SR) 260-Pin DDR4 SODIMM
General Description
CCMTD-1725822587-9885
atf8c1gx64hz.pdf – Rev. F 9/16 EN
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