Data retention mode, Timing, Switching characteristics – Cypress CY7C028V User Manual
Page 8
CY7C027V/027VN/027AV/028V
CY7C037V/037AV/038V
Document #: 38-06078 Rev. *B
Page 8 of 18
Data Retention Mode
The CY7C027V/027VN/027AV/028V and
CY7037V/037AV/038V are designed with battery backup in
mind. 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% of V
CC
during
the power up and power down transitions.
3. The RAM can begin operation >t
RC
after V
CC
reaches the mini-
mum operating voltage (3.0 volts).
t
HD
Data Hold From Write End
0
0
0
ns
t
HZWE
R/W LOW to High Z
10
12
15
ns
t
LZWE
R/W HIGH to Low Z
3
3
3
ns
t
WDD
Write Pulse to Data Delay
30
40
50
ns
t
DDD
Write Data Valid to Read Data Valid
25
30
35
ns
Busy Timing
t
BLA
BUSY LOW from Address Match
15
20
20
ns
t
BHA
BUSY HIGH from Address Mismatch
15
20
20
ns
t
BLC
BUSY LOW from CE LOW
15
20
20
ns
t
BHC
BUSY HIGH from CE HIGH
15
16
17
ns
t
PS
Port Setup for Priority
5
5
5
ns
t
WB
R/W HIGH after BUSY (Slave)
0
0
0
ns
t
WH
R/W HIGH after BUSY HIGH (Slave)
13
15
17
ns
t
BDD
[13]
BUSY HIGH to Data Valid
15
20
25
ns
Interrupt Timing
t
INS
INT Set Time
15
20
20
ns
t
INR
INT Reset Time
15
20
20
ns
Semaphore Timing
t
SOP
SEM Flag Update Pulse (OE or SEM)
10
10
12
ns
t
SWRD
SEM Flag Write to Read Time
5
5
5
ns
t
SPS
SEM Flag Contention Window
5
5
5
ns
t
SAA
SEM Address Access Time
15
20
25
ns
Switching Characteristics
Over the Operating Range
[6]
(continued)
Parameter
Description
CY7C027V/027VN/027AV/028V/
CY7C037V/037AV/038V
Unit
-15
-20
-25
Min
Max
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
Notes
11. For information on port-to-port delay through RAM cells from writing port to reading port, refer to
waveform.
12. Test conditions used are Load 1.
13. t
BDD
is a calculated parameter and is the greater of t
WDD
–t
PWE
(actual) or t
DDD
–t
SD
(actual).
14. CE = V
CC
, V
in
= GND to V
CC
, T
A
= 25
° C. This parameter is guaranteed but not tested.