LMC555_06 Datasheet, PDF (7/12 Pages) National Semiconductor (TI) – CMOS Timer

Application Information (Continued)
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V_CC = 5V
Top Trace: Modulation 1 V/Div.
TIME = 0.2 ms/Div. Bottom Trace: Output Voltage 2 V/Div.
R_A = 9.1 kΩ
C = 0.01 µF
FIGURE 9. Pulse Width Modulator Waveforms
PULSE POSITION MODULATOR
This application uses the timer connected for astable opera-
tion, as in Figure 10, 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. Figure 11 shows the waveforms
generated for a triangle wave modulation signal.
V_CC = 5V
TIME = 0.1 ms/Div.
R_A = 3.9 kΩ
R_B = 3 kΩ
C = 0.01 µF
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Top Trace: Modulation Input 1 V/Div.
Bottom Trace: Output Voltage 2 V/Div.
FIGURE 11. Pulse Position Modulator Waveforms
50% DUTY CYCLE OSCILLATOR
The frequency of oscillation is
f = 1/(1.4 R_CC)
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FIGURE 10. Pulse Position Modulator
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FIGURE 12. 50% Duty Cycle Oscillator
micro SMD Marking Orientation
Top View
Bumps are numbered counter-clockwise
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