HD74LS640 Datasheet, PDF (3/7 Pages) Hitachi Semiconductor – Octal Bus Transceivers(inverted 3-state outputs)

HD74LS640
Switching Characteristics
Item
Propagation delay time
Output enable time
Output disable time
(V_CC = 5 V, Ta = 25°C)
Symbol Inputs Outputs min. typ. max. Unit Condition
A
t_PLH
B
B
—
6
10
ns
A
—
6
10
ns
A
t_PHL
B
G
t_ZL
G
B
—
8
15
ns
A
—
8
15
ns C_L = 45 pF,
A
—
31
40
ns
R_L = 667 Ω
B
—
31
40
ns
G
A
—
23
40
ns
t_ZH
G
B
—
23
40
ns
G
A
—
15
25
ns
t_LZ
G
B
—
15
25
ns
C_L = 5 pF,
G
A
—
15
25
ns
R_L = 667 Ω
t_HZ
G
B
—
15
25
ns
Rev.2.00, Feb.18.2005, page 3 of 6