Switching characteristics – Cypress CY7C138 User Manual
Page 5
CY7C138, CY7C139
Document #: 38-06037 Rev. *D
Page 5 of 17
Figure 2. AC Test Loads and Waveforms
3.0V
GND
90%
90%
10%
< 3 ns
< 3 ns
10%
ALL INPUT PULSES
(a) Normal Load (Load 1)
R1 = 893
Ω
5V
OUTPUT
R2 = 347
Ω
C = 30 pF
R
TH
= 250
Ω
V
TH
= 1.4V
OUTPUT
C = 30pF
(b) Thé venin Equivalent(Load 1)
(c) Three-State Delay (Load 3)
C = 30 pF
OUTPUT
Load (Load 2)
R1 = 893
Ω
R2 = 347
Ω
5V
OUTPUT
C = 5 pF
Note
8. Tested initially and after any design or process changes that may affect these parameters.
Switching Characteristics
Over the Operating Range
Parameter
Description
7C138-15
7C139-15
7C138-25
7C139-25
7C138-35
7C139-35
7C138-55
7C139-55
Unit
Min
Max
Min
Max
Min
Max
Min
Max
READ CYCLE
t
RC
Read Cycle Time
15
25
35
55
ns
t
AA
Address to Data Valid
15
25
35
55
ns
t
OHA
Output Hold From Address Change
3
3
3
3
ns
t
ACE
CE LOW to Data Valid
15
25
35
55
ns
t
DOE
OE LOW to Data Valid
10
15
20
25
ns
t
LZOE
OE Low to Low Z
3
3
3
3
ns
t
HZOE
OE HIGH to High Z
10
15
20
25
ns
t
LZCE
CE LOW to Low Z
3
3
3
3
ns
t
HZCE
CE HIGH to High Z
10
15
20
25
ns
t
PU
CE LOW to Power-Up
0
0
0
0
ns
t
PD
CE HIGH to Power-Down
15
25
35
55
ns
WRITE CYCLE
t
WC
Write Cycle Time
15
25
35
55
ns
t
SCE
CE LOW to Write End
12
20
30
40
ns
t
AW
Address Set-Up to Write End
12
20
30
40
ns
t
HA
Address Hold From Write End
2
2
2
2
ns
t
SA
Address Set-Up to Write Start
0
0
0
0
ns
t
PWE
Write Pulse Width
12
20
25
30
ns
t
SD
Data Set-Up to Write End
10
15
15
20
ns