LMC555
Application Information
(Continued)
00866916
V
CC
= 5V
00866915
Top Trace: Modulation Input 1 V/Div.
Bottom Trace: Output Voltage 2 V/Div.
TIME = 0.1 ms/Div.
R
A
= 3.9 kΩ
R
B
= 3 kΩ
C = 0.01 µF
V
CC
= 5V
TIME = 0.2 ms/Div.
R
A
= 9.1 kΩ
C = 0.01 µF
Top Trace: Modulation 1 V/Div.
Bottom Trace: Output Voltage 2 V/Div.
FIGURE 11. Pulse Position Modulator Waveforms
FIGURE 9. Pulse Width Modulator Waveforms
PULSE POSITION MODULATOR
This application uses the timer connected for astable opera-
tion, as in
with a modulating signal again applied
to the control voltage terminal. The pulse position varies with
the modulating signal, since the threshold voltage and hence
the time delay is varied.
shows the waveforms
generated for a triangle wave modulation signal.
50% DUTY CYCLE OSCILLATOR
The frequency of oscillation is
f = 1/(1.4 R
C
C)
00866906
00866921
FIGURE 12. 50% Duty Cycle Oscillator
micro SMD Marking Orientation
Top View
FIGURE 10. Pulse Position Modulator
00866923
Bumps are numbered counter-clockwise
7
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