EDJ1108BABG, EDJ1116BABG
ODT during Reads
As the DDR3 SDRAM cannot terminate and drive at the same time, RTT must be disabled at least half a clock cycle
before the read preamble by driving the ODT pin low appropriately. RTT may nominally not be enabled until one
clock cycle after the end of the post-amble as shown in the example in the figure below.
Note that ODT may be disabled earlier before the Read and enabled later after the Read than shown in this example
in the figure below.
ODT must be disabled externally during Reads by driving ODT low.
(example: CL = 6; AL = CL - 1 = 5; RL = AL + CL = 11; CWL = 5; ODTLon = CWL + AL -2 = 8;
ODTLoff = CWL + AL - 2 = 8)
T0 T1 T2 T3 T4 T5 T6 T7
T8 T9 T10 T11 T12 T13 T14 T15 T16 End
CK
/CK
READ
Command
Address
A
RL = AL + CL
ODT
ODTLoff = WL – 2 = CWL + AL – 2
ODTLon = WL – 2 = CWL + AL – 2
tAOF (max.)
tAOF (min.)
tAON (min.)
tAON (max.)
RTT
RTT
DRAM_RTT
DQS, /DQS
DQ
out out out out out out out out
0
1
2
3
4
5
6
7
Example of ODT during Reads
Data Sheet E1248E40 (Ver. 4.0)
133
ELPIDA [ ELPIDA MEMORY ]
