MC3456 Motorola, MC3456 Datasheet - Page 8

• Manufacturer Part Number: MC3456
• Description: DUAL TIMING CIRCUIT
• Manufacturer: Motorola

Pulse Width Modulation
monostable mode of operation, the charge time of the
capacitor can be varied by changing the control voltage at
Pin 3. In this manner, the output pulse width can be
modulated by applying a modulating signal that controls the
threshold voltage.
8
If the timer is triggered with a continuous pulse train in the
9.1 k
Threshold
Discharge
1.0 F
Figure 22. Pulse Width Modulation Waveforms
V CC
Trigger
(R A = 10 kW, C = 0.02 mF, V CC = 15 V)
MC3456
Modulation Input Voltage 5.0 V/cm
1/2
Clock Input Voltage
Capacitor Voltage
Output Voltage
t = 0.5 ms/cm
Reset
Gnd
5.0 V/cm
5.0 V/cm
5.0 V/cm
Control
Output
0.01 F
Load
0.001 F
27 k
Figure 24. Sequential Timing Circuit
Threshold
9.1 k
Discharge
5.0 F
Trigger
V CC
MC3456
MC3456
1/2
Gnd
Reset
Test Sequences
sequential timing. An example is shown in Figure 24 where
the sequence is started by triggering the first timer which runs
for 10 ms. The output then switches low momentarily and
starts the second timer which runs for 50 ms and so forth.
Control
Output
Several timers can be connected to drive each other for
0.01 F
Load
Output
Clock
Input
0.001 F
Figure 23. Pulse Width Modulation Circuit
27 k
R L
Output
Trigger
+V CC (5.0 V to 15 V)
MOTOROLA ANALOG IC DEVICE DATA
5 (9)
6 (8)
Discharge
Threshold
50 k
5.0 F
Trigger
Reset
4 (10)
Gnd
MC3456
V CC
1/2
MC3456
V CC
1/2
7
Gnd
14
Reset
Discharge
1 (13)
Threshold
2 (12)
Control
3 (11)
Control
Output
0.01 F
V CC (5.0 V to 15 V)
Modulation
R A
Load
Input
C