74F647 Datasheet, PDF (7/12 Pages) NXP Semiconductors – Octal transceiver/register, non-inverting open-collector

Philips Semiconductors
Octal transceivers/registers (open-collector)
Product specification
74F647/74F649
AC WAVEFORMS (Continued)
For all waveforms, V_M = 1.5V
The shaded areas indicate when the input is permitted to change for predictable output performance.
An or Bn
Bn or An
V_M
t_PLH
V_M
V_M
SBA or SAB
t_PHL
V_M
An or Bn
SF00396
Waveform 3. Propagation Delay, An to Bn or Bn to An and
SBA to An or SAB to Bn
An or Bn
V_M
V_M
t_s(H) t_h(H)
V_M V_M
t_s(L) t_h(H)
CPBA
or
V_M
CPAB
V_M
SF01165
Waveform 4. Data Setup and Hold Times
TYPICAL PROPAGATION DELAYS VERSUS LOAD FOR OPEN COLLECTOR OUTPUTS
18
16
14
t_PLH
12
10
PROPAGATION
DELAY (ns)
t_PHL
8
6
4
2
0
0
100
200
300
400
500
600
LOAD RESISTOR (W)
SF01208
NOTE:
When using open-collector part, the value of the pull-up resistor greatly affects the value of the t_PLH. For example, changing the pull-up resistor
value from 500W to 100W will improve the t_PLH up to 50% with only slight increase in the t_PHL. However, if the pull-up resistor is changed, the
user must take certain that the total I_OL current through the resistor and the total I_IL’s of the receivers do not exceed the I_OL maximum
specification.
1992 Feb 28
7