74hct5555 NXP Semiconductors, 74hct5555 Datasheet - Page 22

• Manufacturer Part Number: 74hct5555
• Description: Programmable Delay Timer With Oscillator
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Minimum Output Pulse Width
The minimum output pulse width is
determined by the minimum clock
pulse width, plus the maximum
propagation delay of A, B to Q. The
rising edge of Q is dominated by the
A, B to Q propagation delay, while the
falling edge of Q is dominated by RS
to Q propagation delay. These
propagation delays are not equal. The
SYNCHRONIZATION LIMITS
September 1993
1
2
3
4
5
6
7
8
.
17
18
19
20
21
22
23
24
Programmable delay timer with oscillator
NUMBER OF STAGES SELECTED
RS to Q propagation delay is some
what longer, resulting in inaccurate
outputs for extremely short pulses.
The propagation delays are listed in
the section 'AC Characteristics'. With
these numbers it is possible to
calculate the maximum deviation (an
example is shown in Fig.16).
Figure 16 is valid for an external clock
where the trigger is synchronized to
the falling edge of the clock only. The
22
18 MHz
14 MHz
11 MHz
9.6 MHz
8.3 MHz
7.3 MHz
6.6 MHz
6 MHz
.
3.2 MHz
3.0 MHz
2.9 MHz
2.8 MHz
2.7 MHz
2.6 MHz
2.5 MHz
2.4 MHz
CLOCK FREQUENCY (TYPICAL)
graph shows that the minimum
programmed pulse width of 100 ns is:
minimum of 4% too long
typically 7% too long
maximum of 10% too long.
74HC/HCT5555
Product specification