HD74LS77 Datasheet, PDF (3/5 Pages) Hitachi Semiconductor – 4-bit Bistable Latches

HD74LS77
Switching Characteristics
Item
Propagation delay
time
(V_CC = 5 V, Ta = 25°C)
Symbol Inputs Outputs min. typ. max. Unit
Condition
tPLH
D
—
11
19
Q
tPHL
tPLH
G
—
—
9
10
17
18
ns
CL = 15 pF,
RL = 2 kΩ
Q
tPHL
—
10
18
Testing Method
Test Circuit
Input
P.G.
Zout = 50Ω
Input
P.G.
Zout = 50Ω
V_CC Output
D
Q
G
RL
CL
Notes:
1. Test is put into the each latch.
2. C_L includes probe and jig capacitance.
3. All diodes are 1S2074(H).
Waveform
Notes:
t_TLH
1µs
t_THL
1µs
90%
D
1.3 V
10%
90%
1.3 V
10%
3V
1.3 V
0V
t_su
t_h
t_su
t_h
t_TLH
t_THL
G
90% 90%
1.3 V 1.3 V
1.3 V 1.3 V
3V
10% 10%
0V
t_w
t_w
t_PLH
Q
1.3 V
t_PLH
t_PHL
t_PHL
1.3 V
V_OH
V_OL
1. Input pulse; t_TLH ≤ 10 ns, t_THL ≤ 10 ns.
2. When measuring propagation delay times from the D input, the corresponding G input must be
held high.
Rev.3.00, Jul.22.2005, page 3 of 4