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MOTOROLA
SEMICONDUCTOR TECHNICAL DATA
Hex Contact Bounce Eliminator
The MC14490 is constructed with complementary MOS enhancement
mode devices, and is used for the elimination of extraneous level changes
that result when interfacing with mechanical contacts. The digital contact
bounce eliminator circuit takes an input signal from a bouncing contact and
generates a clean digital signal four clock periods after the input has
stabilized. The bounce eliminator circuit will remove bounce on both the
"make" and the "break" of a contact closure. The clock for operation of the
MC14490 is derived from an internal R–C oscillator which requires only an
external capacitor to adjust for the desired operating frequency (bounce
delay). The clock may also be driven from an external clock source or the
oscillator of another MC14490 (see Figure 5).
NOTE: Immediately after power–up, the outputs of the MC14490 are in
indeterminate states.
Diode Protection on All Inputs
Six Debouncers Per Package
Internal Pullups on All Data Inputs
Can Be Used as a Digital Integrator, System Synchronizer, or Delay
Line
Internal Oscillator (R–C), or External Clock Source
TTL Compatible Data Inputs/Outputs
Single Line Input, Debounces Both "Make" and "Break" Contacts
Does Not Require "Form C" (Single Pole Double Throw) Input Signal
Cascadable for Longer Time Delays
Schmitt Trigger on Clock Input (Pin 7)
Supply Voltage Range = 3.0 V to 18 V
Chip Complexity: 546 FETs or 136.5 Equivalent Gates
+V DD
A in 1
OSCILLATOR
OSC in 7
AND
TWO–PHASE
CLOCK GENERATOR
OSC out 9
B in 14
C in 3
D in 12
E in 5
F in 10
MC14490
6–210
BLOCK DIAGRAM
DATA
4–BIT STATIC SHIFT REGISTER
SHIFT
LOAD
φ 1
φ 2
IDENTICAL TO ABOVE STAGE
IDENTICAL TO ABOVE STAGE
IDENTICAL TO ABOVE STAGE
IDENTICAL TO ABOVE STAGE
IDENTICAL TO ABOVE STAGE
MC14490
ORDERING INFORMATION
MC14490P
MC14490L
MC14490DW
T A = – 55 to 125 C for all packages.
1/2–BIT
DELAY
φ 1 φ 2
φ 1 φ 2
φ 1
φ 2
2 B out
φ 1
φ 2
13 C out
φ 1
φ 2
4 D out
φ 1
φ 2
11 E out
φ 1
φ 2
6 F out
MOTOROLA CMOS LOGIC DATA
L SUFFIX
CERAMIC
CASE 620
P SUFFIX
PLASTIC
CASE 648
DW SUFFIX
SOIC
CASE 751G
Plastic
Ceramic
SOIC
15 A out
V DD = PIN 16
V SS = PIN 8
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