K4E661612C,K4E641612C
16.
t
CWL
is specified from W falling edge to the earlier CAS rising edge.
17.
t
CSR
is referenced to earlier CAS falling before RAS transition low.
18.
t
CHR
is referenced to the later CAS rising high after RAS transition low.
CMOS DRAM
RAS
LCAS
UCAS
t
CSR
t
CHR
19.
t
DS
is specified for the earlier CAS falling edge and
t
DH
is specified by the later CAS falling edge in early write cycle.
LCAS
UCAS
t
DS
DQ0 ~ DQ15
Din
t
DH
20. If RAS goes high before CAS high going, the open circuit condition of the output is achieved by CAS high going.
21.
t
ASC
鈮?ns,
Assume t
T
=2.0ns, if t
ASC
鈮?ns,
then t
HPC
(min) and t
CAS
(min) must be increased by the value of "6ns-t
ASC
".
22. If
t
RASS
鈮?00us,
then RAS precharge time must use
t
RPS
instead of
t
RP
.
23. For RAS-only-Refresh and Burst CAS-before-RAS refresh mode, 4096 cycles(4K/8K) of burst refresh must be executed within
64ms before and after self refresh, in order to meet refresh specification.
24. For distributed CAS-before-RAS with 15.6us interval, CBR refresh should be executed with in 15.6us immediately before and
after self refresh in order to meet refresh specification.