HCC4541B Datasheet, PDF (6/10 Pages) STMicroelectronics – PROGRAMMABLE TIMER

HCF4541B
DYNAMIC ELECTRICAL CHARACTERISTICS (T_amb = 25°C, C_L = 50pF, R_L = 200KΩ, t_r = t_f = 20 ns)
Symbol
Parameter
V_DD (V)
(2⁸) ^{Propagation Delay Time}
5
t_PHL t_PLH ^{(CLOCK to Q)}
10
15
(2¹⁶) ^{Propagation Delay Time}
5
t_PHL t_PLH ^{(CLOCK to Q)}
10
15
t_THL Transition Time
5
10
15
t_TLH Transition Time
5
10
15
Master Reset, Clock Pulse
5
Width
10
15
f_CL Maximum Clock Pulse
5
Input Frequency
10
15
t_r, t_f Maximum Clock Pulse
5
Input Rise or Fall Time
10
15
(*) Typical temperature coefficient for all V_DD value is 0.3 %/°C.
Test Condition
Value (*)
Unit
Min.
900
300
225
Typ.
3.5
1.25
0.9
6
3.5
2.5
100
50
40
180
90
65
300
100
85
1.5
4
6
Max.
10.5
3.8
2.9
18
10
7.5
200
100
80
360
180
130
µs
µs
ns
ns
ns
MHz
Unlimited
µs
DIGITAL TIMER APPLICATION
A positive MASTER RESET pulse clears the
counter and latch. The Output goes high and
keeps up till the number of pulses, selected by A
and B , are counted. This circuit is retriggerable
and is as accurate as the input frequency. If a
more accurate circuit is desired, an external clock
can be used on pin 3. A set-up time equal to the
width of the one shot output is required
immediately following initial power up, during
which time the output will be high
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