Order this document by MC3456/D
Dual Timing Circuit
The MC3456 dual timing circuit is a highly stable controller capable of
producing accurate time delays, or oscillation. Additional terminals are
provided for triggering or resetting if desired. In the time delay mode of
operation, the time is precisely controlled by one external resistor and
capacitor per timer. For astable operation as an oscillator, the free running
frequency and the duty cycle are both accurately controlled with two external
resistors and one capacitor per timer. The circuit may be triggered and reset
on falling waveforms, and the output structure can source or sink up to
200 mA or drive MTTL circuits.
•
Direct Replacement for NE556/SE556 Timers
MC3456
DUAL TIMING CIRCUIT
SEMICONDUCTOR
TECHNICAL DATA
•
•
•
•
•
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Timing from Microseconds through Hours
Operates in Both Astable and Monostable Modes
Adjustable Duty Cycle
High Current Output can Source or Sink 200 mA
Output can Drive MTTL
Temperature Stability of 0.005% per
°C
Normally “On” or Normally “Off” Output
Dual Version of the Popular MC1455 Timer
P SUFFIX
PLASTIC PACKAGE
CASE 646
D SUFFIX
PLASTIC PACKAGE
CASE 751
(SO–14)
PIN CONNECTIONS
Discharge A
Threshold A
1
2
3
4
5
6
7
14
13
12
11
10
9
8
VCC
Discharge B
Threshold B
Control B
Reset B
Output B
Trigger B
Figure 1. 22 Second Solid State Time Delay Relay Circuit
1.0 k
MT2
3
10 k
5
0.01
µF
4
2
8
1/2
MC3456
1
6
7
1.0
µF
C
–10 V
t = 1.1; R and C = 22 sec
Time delay (t) is variable by
changing R and C (see Figure 16).
1N4740
3.5 k
250 V
1N4003
–
10
µF
+
R
20 M
G
MT1
Load
117 Vac/60 Hz
Control A
Reset A
Output A
Trigger A
Gnd
0.1
µF
(Top View)
ORDERING INFORMATION
Device
MC3456P
Operating
Temperature Range
0° to +70°C
Package
Plastic DIP
SO–14
Figure 3. General Test Circuit
VR
Reset
5
Control
Voltage
3
Output
VO
ISink
ISource
Gnd
1
2
6 (8)
4
8
VCC
1/2
MC3456
7
Discharge
Threshold
6
Trigger
Ith
2.0 k
VS
2 (12)
Threshold
3 (11)
Control Voltage
ICC
700
VCC
NE556D
Figure 2. Block Diagram
(1/2 Shown)
VCC
14
5k
+
Comp
A
–
5k
+
Comp
–B
5k
7
Gnd
4 (10)
Reset
Flip
R Flop
Q
S Inhibit/
Reset
5 (9)
Output
1 (13)
Discharge
+
0.01
µF
Trigger
Test circuit for measuring DC parameters (to set output and measure parameters):
a) When VS
2/3 VCC, VO is low.
b) When VS 1/3 VCC, VO is high.
c) When VO is low, Pin 7 sinks current. To test for Reset, set VO high,
c)
apply Reset voltage, and test for current flowing into Pin 7. When Reset
c)
is not in use, it should be tied to VCC.
w
v
©
Motorola, Inc. 1996
Rev 2
MOTOROLA ANALOG IC DEVICE DATA
1
MOTOROLA [ MOTOROLA, INC ]
