MO SEL VITELIC
V53C8125H
Fast Page Mode provides sustained data rates
up to 53 MHz for applications that require high data
rates such as bit-mapped graphics or high-speed
signal processing. The following equation can be
used to calculate the maximum data rate:
Power-On
After application of the V
supply, an initial
CC
pause of 200 µs is required followed by a minimum
of 8 initialization cycles (any combination of cycles
containing a RAS clock). Eight initialization cycles
are required after extended periods of bias without
clocks (greater than the Refresh Interval).
256
Data Rate = ----------------------------------------
t
+ 255 × t
RC
PC
During Power-On, the V current requirement of
CC
the V53C8125H is dependent on the input levels of
RAS and CAS. If RAS is low during Power-On, the
Data Output Operation
The V53C8125H Input/Output is controlled by
OE, CAS, WE and RAS. A RAS low transition en-
ables the transfer of data to and from the selected
row address in the Memory Array. A RAS high tran-
sition disables data transfer and latches the output
data if the output is enabled. After a memory cycle
is initiated with a RAS low transition, a CAS low
transition or CAS low level enables the internal I/O
path. A CAS high transition or a CAS high level dis-
ables the I/O path and the output driver if it is en-
abled. A CAS low transition while RAS is high has
no effect on the I/O data path or on the output driv-
ers. The output drivers, when otherwise enabled,
can be disabled by holding OE high. The OE signal
has no effect on any data stored in the output latch-
es. A WE low level can also disable the output driv-
ers when CAS is low. During a Write cycle, if WE
goes low at a time in relationship to CAS that would
normally cause the outputs to be active, it is neces-
sary to use OE to disable the output drivers prior to
the WE low transition to allow Data In Setup Time
device will go into an active cycle and I will exhibit
DD
current transients. It is recommended that RAS and
CAS track with V or be held at a valid V during
CC
IH
Power-On to avoid current surges.
Table 1. V53C8125H Data Output
Operation for Various Cycle Types
Cycle Type
I/O State
Read Cycles
Data from Addressed
Memory Cell
CAS-Controlled Write
Cycle (Early Write)
High-Z
WE-Controlled Write
Cycle (Late Write)
OE Controlled.
High OE = High-Z I/Os
Read-Modify-Write
Cycles
Data from Addressed
Memory Cell
Fast Page Mode
Read
Data from Addressed
Memory Cell
Fast Page Mode Write
Cycle (Early Write)
High-Z
(t ) to be satisfied.
DS
Fast Page Mode Read-Modify-
Write Cycle
Data from Addressed
Memory Cell
RAS-only Refresh
High-Z
CAS-before-RAS
Refresh Cycle
Data remains as in
previous cycle
CAS-only Cycles
High-Z
V53C8125H Rev. 1.7 August 1998
15
MOSEL [ MOSEL VITELIC, CORP ]
