LMC555CM National Semiconductor, LMC555CM Datasheet - Page 7

• Manufacturer Part Number: LMC555CM
• Description: IC, TIMER, SINGLE, 3MHZ, 15V, 8-SOIC
• Manufacturer: National Semiconductor

Specifications of LMC555CM

• Operating Mode: Astable
• No. Of Timers: 1
• Clock External Input: Yes
• Supply Voltage Range: 2V To 15V
• Digital Ic Case Style: SOIC
• No. Of Pins: 8
• Frequency: 3MHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

V
TIME = 0.2 ms/Div. Bottom Trace: Output Voltage 2 V/Div.
R
C = 0.01 µF
PULSE POSITION MODULATOR
This application uses the timer connected for astable opera-
tion, as in
to the control voltage terminal. The pulse position varies with
the modulating signal, since the threshold voltage and hence
the time delay is varied.
erated for a triangle wave modulation signal.
CC
A
= 9.1 kΩ
= 5V
FIGURE 9. Pulse Width Modulator Waveforms
FIGURE 10. Pulse Position Modulator
Figure
10, with a modulating signal again applied
Top Trace: Modulation 1 V/Div.
Figure 11
shows the waveforms gen-
866915
866921
7
V
TIME = 0.1 ms/Div.
R
R
C = 0.01 µF
50% DUTY CYCLE OSCILLATOR
The frequency of oscillation is
CC
A
B
= 3.9 kΩ
= 3 kΩ
= 5V
FIGURE 11. Pulse Position Modulator Waveforms
f = 1/(1.4 R
FIGURE 12. 50% Duty Cycle Oscillator
micro SMD Marking Orientation
C
C)
Bottom Trace: Output Voltage 2 V/Div.
Top Trace: Modulation Input 1 V/Div.
Top View
866926
866916
www.national.com
866906