Cypress CY7C0251AV Manual De Usuario
CY7C024AV/024BV/025AV/026AV
CY7C0241AV/0251AV/036AV
Document #: 38-06052 Rev. *J
Page 10 of 19
Data Retention Mode
The CY7C024AV/024BV/025AV/026AV and
CY7C0241AV/0251AV/036AV are designed for battery backup.
Data retention voltage and supply current are guaranteed over
temperature. The following rules ensure data retention:
CY7C0241AV/0251AV/036AV are designed for battery backup.
Data retention voltage and supply current are guaranteed over
temperature. The following rules ensure data retention:
1. Chip Enable (CE) must be held HIGH during data retention,
within V
CC
to V
CC
– 0.2V.
2. CE must be kept between V
CC
– 0.2V and 70 percent of V
CC
during the power up and power down transitions.
3. The RAM can begin operation >t
RC
after V
CC
reaches the
minimum operating voltage (3.0V).
Notes
25. For information on port to port delay through RAM cells from writing port to reading port, refer to
.
26. Test conditions used are Load 2.
27. t
27. t
BDD
is a calculated parameter and is the greater of t
WDD
– t
PWE
(actual) or t
DDD
– t
SD
(actual).
28. CE = V
CC
, V
in
= GND to V
CC
, T
A
= 25
°C. This parameter is guaranteed but not tested.
t
PWE
Write Pulse Width
15
20
ns
t
SD
Data Setup to Write End
15
15
ns
t
HD
Data Hold From Write End
0
0
ns
t
HZWE
R/W LOW to High Z
12
15
ns
t
LZWE
R/W HIGH to Low Z
3
0
ns
t
WDD
Write Pulse to Data Delay
45
50
ns
t
DDD
[25]
Write Data Valid to Read Data Valid
30
35
ns
Busy Timing
t
BLA
BUSY LOW from Address Match
20
20
ns
t
BHA
BUSY HIGH from Address Mismatch
20
20
ns
t
BLC
BUSY LOW from CE LOW
20
20
ns
t
BHC
BUSY HIGH from CE HIGH
17
17
ns
t
PS
Port Setup for Priority
5
5
ns
t
WB
R/W HIGH after BUSY (Slave)
0
0
ns
t
WH
R/W HIGH after BUSY HIGH (Slave)
15
17
ns
t
BDD
BUSY HIGH to Data Valid
20
25
ns
Interrupt Timing
t
INS
INT Set Time
20
20
ns
t
INR
INT Reset Time
20
20
ns
Semaphore Timing
t
SOP
SEM Flag Update Pulse (OE or SEM)
10
12
ns
t
SWRD
SEM Flag Write to Read Time
5
5
ns
t
SPS
SEM Flag Contention Window
5
5
ns
t
SAA
SEM Address Access Time
20
25
ns
Switching Characteristics
Over the Operating Range (continued)
[20]
Parameter
Description
CY7C024AV/024BV/025AV/026AV
CY7C0241AV/0251AV/036AV
Unit
-20
-25
Min
Max
Min
Max
Timing
Parameter
Test Conditions
Max
Unit
ICC
DR1
at VCC
DR
= 2V
50
μA
Data Retention Mode
3.0V
3.0V
V
CC
> 2.0V
V
CC
to V
CC
– 0.2V
V
CC
CE
t
RC
V
IH