SN74LS221 查看數據表（PDF） - Motorola => Freescale
零件编号
产品描述 (功能)
生产厂家
SN74LS221 Datasheet PDF : 7 Pages
| |||
SN54 / 74LS221
AC CHARACTERISTICS (VCC = 5.0 V, TA = 25°C)
Symbol
From
(Input)
To
(Output)
Limits
Min Typ Max Unit
tPLH
A
Q
B
Q
45
70
ns
35
55
tPHL
A
Q
B
Q
50
80
ns
40
65
tPHL
tPLH
Clear
Clear
Q
35
55
ns
Q
44
65
ns
70 120 150
tW(out)
A or B
Q or Q
20
47
70
ns
600 670 750
6.0 6.9 7.5 ms
AC SETUP REQUIREMENTS (VCC = 5.0 V, TA = 25°C)
Symbol
dv/dt
Parameter
Rate of Rise or Fall of Input Pulse
tW
ts
Rext
Cext
Input Pulse Width
Clear-Inactive-State Setup Time
External Timing Resistance
External Timing Capacitance
Output Duty Cycle
Schmitt, B
Logic Input, A
A or B, tW(in)
Clear, tW (clear)
54
74
RT = 2.0 kΩ
RT = MAX Rext
Test Conditions
Cext = 80 pF, Rext = 2.0 Ω
CL = 15 pF,
See Figure 1
Cext = 80 pF, Rext = 2.0 Ω
Cext = 0, Rext = 2.0 kΩ
Cext = 100 pF, Rext = 10 kΩ
Cext = 1.0 µF, Rext = 10 kΩ
Limits
Min
Typ
Max
1.0
1.0
40
40
15
1.4
70
1.4
100
0
1000
50
90
Unit
V/s
V/µs
ns
ns
kΩ
µF
%
FAST AND LS TTL DATA
5-383
Share Link: 