Semiconductor MSC23V43257D
Notes: 1. A start-up delay of 200µs is required after power-up, followed by a minimum of eight initializati on cycles
(/RAS only r efresh or /CAS before /RAS ref r esh) before proper device operation is achiev ed.
2. The AC characteristics assume t
T
= 2ns.
3. V
IH
(Min.) and VIL(Max.) are reference level s for measuring input ti ming signals. Transition times (tT) are
measured between V
IH
and VIL.
4. This paramet er is measured with a load ci r c uit equivalent to 1 TTL load and 100pF.
The output timing reference levels are V
OH
= 2.0V and V
OL
= 0.8V.
5. Operation wit hin the t
RCD
(Max.) limi t ensures 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
the access tim e is controlled by t
CAC
.
6. Operation wit hin the t
RAD
(Max.) limi t ensures 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
the access tim e is controlled by t
AA
.
7. t
CEZ
(Max.), t
REZ
(Max.), t
WEZ
(Max.) and t
OEZ
(Max.) def i ne the ti m e at which the out put achieves the open
circui t condition and are not referenced to output voltage levels.
8. t
CEZ
or t
REZ
must be satisfied for open circuit condition.
9. t
RCH
or t
RRH
must be satisfi ed for a read cycle.
10. t
WCS
, t
CWD
, t
RWD
, t
AWD
and t
CPWD
are not restricti v e operati ng parameter s. They are incl uded in the data
sheet as electric al characteristics only. If t
WCS ≥ tWCS
(Min.), then t he cycle is an early write cycle and the
data out will remain open circuit (high i mpedance) throughout the enti r e cycle. If t
CWD
≥ t
CWD
(Min.), t
RWD
≥ t
RWD
(Min.), t
AWD
≥ t
AWD
(Min.) and t
CPWD
≥ t
CPWD
(Min.), then the cycl e is a read modif y write cycle and
data ou t w ill c on ta in d a ta r ead from the selected cell; if neither of the above sets of conditions is satisfied,
then the condition of the data out (at access time) is indeterminate.
11. These parameters are referenced to the /CAS leading edge in an early write cycle, and to the /WE
leading edge in an /OE control write cycle, or a read modify write cycle.
12. The test mode is initiated by performing a /WE and /CAS before /RAS ref resh cycle. This mode is
latched and remains in effect until the exit cycle is generated. The test mode specified in this data sheet
is an 8-bit parallel test functi on. CA0, CA1 and CA10 are not used. In a read cycle, if all internal bits are
equal, the DQ pin will indic ate a hig h le vel. If an y in te rn al b its a re no t equal, the DQ pin will indica te a lo w
levels. The test mode is cleared and the memory device returned to its normal operating state by
performing a /RAS only refresh cycle or a /CAS before /RAS refresh cycle.
13. In a test mode read cycle, the value of access time parameters is delayed for 5ns for the specified value.
These parameters should be specifi ed in test m ode cycle by adding the abov e v alue t o the specif ied
value in this data sheet.