HD74LS122 Datasheet, PDF (5/8 Pages) Hitachi Semiconductor – Retriggerable Monostable Multivibrators(with Clear)

HD74LS122
Typical Application Data for HD74LS122
For pulse widths when C_ext ≤ 1000 pF, See Figure 3.
The output pulse is primarily a function of the external capacitor and resistor. For C_ext > 1000 pF, the output pulse
width (t_w) is defined as: t_w(out) = K • R_ext • C_ext; See Figure 4.
V_CC
Rext
+
– ^Cext
to Cext to Rext/Cext
Rext (kΩ)
Cext (pF)
t_w(out) (ns)
Figure 2
Timing Component Connections
100,000
10,000
Rext = 160kΩ
Figure 3
1,000
100
10
1
Rext = 80kΩ
40kΩ
20kΩ
10kΩ
5kΩ
10
100
1,000
External capacitance Cext (pF)
Typical Output Pulse Width (Cext ≤ 1000 pF)
0.5
0.4
0.3
0.2
0.1
V_CC = 5V
Ta = 25°C
0
10³ 2 3 5 710⁴ 2 3 5 710⁵ 2 3 5 710⁶ 2 3 5 710⁷
Timing capacitance Cext (pF)
Figure 4
C_ext vs. K (C_ext > 1000 pF)
Rev.2.00, Feb.18.2005, page 5 of 7