CY7C027V/028V
CY7C037V/038V
Document #: 38-06078 Rev. *A
Page 8 of 18
Data Retention Mode
The CY7C027V/028V and CY7037V/038V are designed with
battery backup in mind. Data retention voltage and supply cur-
rent are guaranteed over temperature. The following rules en-
sure data retention:
1. Chip enable (CE) must be held HIGH during data retention, with-
in VCC to VCC – 0.2V.
2. CE must be kept between VCC – 0.2V and 70% of VCC
during the power-up and power-down transitions.
3. The RAM can begin operation >tRC after VCC reaches the min-
imum operating voltage (3.0 volts).
tHD
Data Hold From Write End
0
0
0
ns
tHZWE
[14, 15]
R/W LOW to High Z
10
12
15
ns
tLZWE
[14 ,15]
R/W HIGH to Low Z
3
3
3
ns
tWDD
[41]
Write Pulse to Data Delay
30
40
50
ns
tDDD
[41]
Write Data Valid to Read Data Valid
25
30
35
ns
Busy Timing[16]
tBLA
BUSY LOW from Address Match
15
20
20
ns
tBHA
BUSY HIGH from Address Mismatch
15
20
20
ns
tBLC
BUSY LOW from CE LOW
152020
ns
tBHC
BUSY HIGH from CE HIGH
15
16
17
ns
tPS
Port Set-Up for Priority
5
5
5
ns
tWB
R/W HIGH after BUSY (Slave)
000
ns
tWH
R/W HIGH after BUSY HIGH (Slave)
13
15
17
ns
tBDD
[18]
BUSY HIGH to Data Valid
15
20
25
ns
Interrupt Timing[16]
tINS
INT Set Time
15
20
20
ns
tINR
INT Reset Time
15
20
20
ns
Semaphore Timing
tSOP
SEM Flag Update Pulse (OE or SEM)10
10
12
ns
tSWRD
SEM Flag Write to Read Time
5
5
5
ns
tSPS
SEM Flag Contention Window
5
5
5
ns
tSAA
SEM Address Access Time
15
20
25
ns
Switching Characteristics Over the Operating Range[11](continued)
Parameter
Description
CY7C037V/038V
Unit
-15
-20
-25
Min.
Max.
Min.
Max.
Min.
Max.
Timing
Parameter
Test Conditions[19]
Max.
Unit
ICCDR1
@ VCCDR = 2V
50
µA
16. For information on port-to-port delay through RAM cells from writing port
to reading port, refer to Read Timing with Busy waveform.
17. Test conditions used are Load 1.
18. tBDD isacalculatedparameterandisthegreateroftWDD–tPWE(actual)ortDDD–tSD
(actual).
19. CE = VCC, Vin = GND to VCC, TA = 25° C. This parameter is guaranteed
but not tested.
Data Retention Mode
3.0V
3.0V
VCC > 2.0V
VCC to VCC – 0.2V
VCC
CE
tRC
V
IH
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