mc33187d Freescale Semiconductor, Inc, mc33187d Datasheet - Page 5

• Manufacturer Part Number: mc33187d
• Description: Long Duration Automotive Timer
• Manufacturer: Freescale Semiconductor, Inc

drive feature of the long duration timer.
are as previously described. Although the circuit is not
intended to be allowed to time out, Rt and Ct need to be
included as it is necessary for the timer to run for the internal
debounce timer to be reset.
momentary type.
run, while R1 ensures that D1 is reverse biassed when the
switch is operated (open). C1 is included to provide a time
constant RinC1 to delay the detection of a toggle input.
toggle input is then recognised and the relay output changes
state assuming that the switch has been released, the
oscillator is stopped and the sequence above can be
repeated.
MC33187
This circuit is designed to just use the toggle and relay
The functions of components Rs, Cs, Rt, Ct, Rin and Dz
The control switch S1 needs to be a normally closed
While it is closed, D1 ensures that the oscillator does not
Thus the operation of the circuit is as follows :
When S1 is operated, the oscillator is allowed to start ; the
D1
Dz
Batt
Ct
Rin
C1
Freescale Semiconductor, Inc.
Rt
For More Information On This Product,
S1
Figure 3.
RC
GND
Relay
Toggle
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Relay Drive and Latch (No Timeout
MOTOROLA
MC33187
R1
N / C
N / C
Vcc
values recommended below, after it has been used to switch
the relay on the circuit will time out and the relay switch off.
No further action takes place until the circuit is reset by
releasing the button.
switch the relay off, nothing happens until the circuit is reset
by releasing the button.
(start up time and basic frequency of oscillator/switch to
toggle delay time) and need to stay in the ratio (1:10).
TS
If the switch is held operated for 9 seconds, with the
If the switch is held operated after it has been used to
Recommended values :
Rs = 1KΩ
Cs = 100nF
Rt = 220KΩ
Ct = 10nF
Rin = 100KΩ
R1 = 1KΩ
C1 = 220nF
Dz = MZD16
D1 = 1N4148
Note that the time constant RtCt and RinC1 are related
Cs
Rs
Batt
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