
Rev.1
Page 14 
Notes :
  1. AC measurements assume t
T 
= 2ns.
 2. An initial pause of 100 
 is required after power up, and it followed by a minimum of eight
initialization cycles (RAS - only refresh cycle or CAS - before - RAS refresh cycle). If the internal
refresh counter is used, a minimun of eight CAS - before - RAS refresh cycles are required.
3. In delayed write or read-modify-write cycles, OE must disable output buffer prior to applying data to
the device.
4. All the V
CC 
and V
SS
 pins shall be supplied with the same voltages. 
5. t
RAS
(min) = t
RWD
(min)+t
RWL
(min)+t
T
 in read-modify-write cycle.
6. t
CAS
(min) = t
CWD
(min)+t
CWL
(min)+t
T
 in read-modify-write cycle.
7. t
ASC
(min), t
RCS
(min), t
WCS
(min), and t
RPC
 are determined by the falling edge of CAS .
8. t
RCD
(max) is specified as a reference point only, and  t
RAC
(max) can be met with the t
RCD
(max) limit.
Otherwise, t
RAC
 is controlled exclusively by t
CAC 
if  t
RCD
 is greater than the specified t
RCD
(max) limit.  
9. t
RAD
(max) is specified as a reference point only, and t
RAC
(max) can be met with the t
RAD
(max) limit.
Otherwise, t
RAC 
is controlled exclusively by t
AA 
if t
RAD 
is greater than the specified t
RAD
(max) limit.  
10. t
CRP
, t
CHR
, t
RCH
, t
CPA
 and t
CPW
 are determined by the rising edge of  CAS .
 11. V
IH
(min) and V
IL
(max) are reference levels for measuring timing or input signals. Therefore, transition
time is measured between V
IH
 and V
IL
.
   12. Assumes that t
RCD
 t
RCD
(max) and t
RAD
 t
RAD
(max). If t
RCD
 or t
RAD
 is greater than the maximum 
recommended value shown in this table, t
RAC
 exceeds the value shown.
≥
 13. Assumes that 
(max) and
(max). 
 14. Access time is determined by the maximum of t
AA
, t
CAC
,  t
CPA
.
 15. Assumes that 
(max) and 
(max). 
 16. Either t
RCH
 or t
RRH
 must be satisfied for a read cycle.
 17. t
OFF
(max) and t
OEZ
(max) define the time at which the output achieves the open circuit condition (high
impedance). t
OFF
 is determined by the later rising edge of RAS or CAS.
 18. t
WCS
, t
RWD
, t
CWD
, and t
AWD
 are not restrictive operating parameters. They are included in the data
sheet as electrical characteristics only. If 
(min), the cycle is an early write cycle and the
data out will remain open circuit (high impedance) throughout the entire cycle. If 
(min),
(min),   
(min) and  
(min), the cycle is a read-modify-write and
the data output will contain data read from the selected cell. If neither of the above sets of conditions
is satisfied, the condition of the data output (at access time) is indeterminate.
 19. These parameters are referenced to CAS separately in an early write cycle and to WE edge in a
delayed write or a read-modify-write cycle.
  20.  t
RASP
 defines RAS pulse width in EDO page mode cycles.
μ
s
≤
≤
t
RCD
t
RCD
t
RAD
t
RAD
≤
t
RCD
t
RCD
≤
t
RAD
t
RAD
≥
t
WCS
t
WCS
≥
t
RWD
t
RWD
≥
t
CWD
t
CWD
≥
t
AWD
t
AWD
≥
t
CPW
t
CPW
≥