K4E660411D, K4E640411D
NOTES
CMOS DRAM
1. An initial pause of 200us is required after power-up followed by any 8 RAS-only refresh or CAS-before-RAS refresh cycles
before proper device operation is achieved.
2. V
IH
(min) and V
IL
(max) are reference levels for measuring timing of input signals. Transition times are measured between
V
IH
(min) and V
IL
(max) and are assumed to be 2ns for all inputs.
3. Measured with a load equivalent to 2 TTL load and 100pF.
4. Operation within the
t
RCD
(max) limit insures that
t
RAC
(max) can be met.
t
RCD
(max) is specified as a reference point only.
If
t
RCD
is greater than the specified
t
RCD
(max) limit, then access time is controlled exclusively by
t
CAC
.
5. Assumes that
t
RCD
≥
t
RCD
(max).
6. This parameter defines the time at which the output achieves the open circuit condition and is not referenced to V
oh
or V
ol
.
7.
t
WCS
,
t
RWD
,
t
CWD
and
t
AWD
are non restrictive operating parameters. They are included in the data sheet as electrical char-
acteristics only. If
t
WCS
≥
t
WCS
(min), the cycle is an early write cycle and the data output will remain high impedance for the
duration of the cycle. If
t
CWD
≥
t
CWD
(min),
t
RWD
≥
t
RWD
(min) and
t
AWD
≥
t
AWD
(min), then the cycle is a read-modify-write cycle
and the data output will contain the data read from the selected address. If neither of the above conditions is satisfied, the
condition of the data out is indeterminate.
8. Either
t
RCH
or
t
RRH
must be satisfied for a read cycle.
9. These parameters are referenced to CAS falling edge in early write cycles and to W falling edge in OE controlled write cycle
and read-modify-write cycles.
10. Operation within the
t
RAD
(max) limit insures that
t
RAC
(max) can be met.
t
RAD
(max) is specified as a reference point only.
If
t
RAD
is greater than the specified
t
RAD
(max) limit, then access time is controlled by
t
AA
.
11. These specifications are applied in the test mode.
12. In test mode read cycle, the value of
t
RAC
,
t
AA
,
t
CAC
is delayed by 2ns to 5ns for the specified values. These parameters
should be specified in test mode cycles by adding the above value to the specified value in this data sheet.
13.
t
ASC
≥6ns,
Assume t
T
= 2.0ns
14. If RAS goes high before CAS high going, the open circuit condition of the output is achieved by CAS high going. If CAS goes
high before RAS high going, the open circuit condition of the output is achieved by RAS high going.
15. If
t
RASS
≥100us,
then RAS precharge time must use
t
RPS
instead of
t
RP
.
16. For RAS-only refresh and burst CAS-before-RAS refresh mode, 4096(4K/8K) cycles of burst refresh must be executed within
64ms before and after self refresh, in order to meet refresh specification.
17. For distributed CAS-before-RAS with 15.6us interval CAS-before-RAS refresh should be executed with in 15.6us immedi-
ately before and after self refresh in order to meet refresh specification.
SAMSUNG [ SAMSUNG SEMICONDUCTOR ]
