MC1455, B
Timing Circuit
The MC1455 monolithic 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, time is
precisely controlled by one external resistor and capacitor. 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. 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 NE555 Timers
SEMICONDUCTOR
TECHNICAL DATA
Timing from Microseconds through Hours
Operates in Both Astable and Monostable Modes
Adjustable Duty Cycle
High Current Output Can Source or Sink 200 mA
P1 SUFFIX
PLASTIC PACKAGE
CASE 626
Output Can Drive MTTL
Temperature Stability of 0.005% per °C
8
1
Normally ON or Normally OFF Output
D SUFFIX
PLASTIC PACKAGE
CASE 751
(SO–8)
8
1
ORDERING INFORMATION
Figure 1. 22 Second Solid State Time Delay Relay Circuit
1.0 k
Load
MT2
3
4
2
10 k
0.1 µF
8
6
MC1455
5
0.01 µF
R
7
1.0 µF
1
MT1
G
20 M
C
MC1455P1
MC1455BD
3.5 k
250 V
–
10 µF
+
+
0.01 µF
VCC
8
Reset
5
Control
Voltage
3
Threshold
+
Comp
A
–
5
Control Voltage
7
ICC
Trigger
2
S Inhibit/
Reset
1
Gnd
Plastic DIP
3
ISink
ISource
VCC
8
700
VCC 7
Discharge
MC1455
Threshold
6
Gnd
1
Trigger
Ith
2.0 k
VS
2
Output
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
c) high, apply Reset voltage, and test for current flowing into Pin 7.
c) When Reset is not in use, it should be tied to VCC.
w
v
5k
11–6
VO
Q
+
Comp
–B
SO–8
4
Output
Discharge
Flip
R Flop
5k
SO–8
Figure 3. General Test Circuit
Figure 2. Representative Block Diagram
5k
Plastic DIP
TA = – 40° to +85°C
VR
6
Package
TA = 0° to +70°C
MC1455D
MC1455BP1
1N4740
Operating
Temperature Range
1N4003
–10 V
t = 1.1; R and C = 22 sec
Time delay (t) is variable by
changing R and C (see Figure 16).
Device
117 Vac/60 Hz
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TIMING CIRCUIT
4
Reset
MOTOROLA ANALOG IC DEVICE DATA