Data retention mode, Timing, Switching characteristics – Cypress CY7C0251AV User Manual
Page 10
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:
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
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
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