Am28F256A 25
AC Characteristics—Write/Erase/Program Operations
Notes:
1. Read timing characteristics during read/write operations are the same as during read-only operations. Refer to AC
Characteristics for Read Only operations.
2. Embedded program operation of 14 µs consists of 10 µs program pulse and 4 µs write recovery before read. This is the
minimum time for one pass through the programming algorithm.
3. Embedded erase operation of 5 sec consists of 4 sec arra y pre-programming time and 1 sec arra y erase time. This is a typical
time for one embedded erase operation.
4. Not 100% tested.
Parameter Symbo ls
Parameter Description
Am28F256A Speed Options
UnitJEDEC Standard -70 -90 -120 -150 -200
t
AVAV
t
WC
Write Cycle Time (Note 4) Min 70 90 120 150 200 ns
t
AVWL
t
AS
Address Setup Time Min00000ns
t
WLAX
t
AH
Address Hold Time Min 45 45 50 60 75 ns
t
DVWH
t
DS
Data Setup Time Min 45 45 50 50 50 ns
t
WHDX
t
DH
Data Hold Time Min 10 10 10 10 10 ns
t
OEH
Output Enable Hold Time for
Embedded Algorithm only
Min 10 10 10 10 10 ns
t
GHWL
Read Recovery Time before WriteMin00000µs
t
ELWLE
t
CSE
Chip Enable Embedded Algorithm
Setup Time
Min 20 2 0 2 0 20 20 ns
t
WHEH
t
CH
Chip Enable Hold Time Min00000ns
t
WLWH
t
WP
Write Pulse Width Min 45 45 50 60 60 ns
t
WHWL
t
WPH
Write Pulse Width HIGH Min 20 20 20 20 20 ns
t
WHWH3
Embedded Programming Operation
(Note 2)
Min 14 14 14 14 14 µs
t
WHWH4
Embedded Erase Operation (Note3)Typ55555sec
t
VPEL
V
PP
Setup Time to Chip Enable LOW
(Note 4)
Min 100 100 100 100 100 ns
t
VCS
V
CC
Setup Time to Chip Enable LOW
(Note 4)
Min 50 50 50 50 50 µs
t
VPPR
V
PP
Rise Time 90% V
PPH
(Note 4) Min 500 500 500 500 500 ns
t
VPPF
V
PP
Fall Time 90% V
PPL
(Note 4) Min 500 500 500 500 500 ns
t
LKO
V
CC
< V
LK O
to Reset (Note 4) Min 100 100 100 100 100 ns
