74F621 Datasheet, PDF (6/10 Pages) NXP Semiconductors – Octal bus transceiver, non-inverting open collector

Philips Semiconductors
Octal bus transceiver, non-inverting (open collector)
Product specification
74F621
TYPICAL PROPAGATION DELAYS VERSUS LOAD FOR OPEN COLLECTOR OUTPUTS
18
16
14
12
t_PLH
10
Propagation
delay (ns) ₈
6
t_PHL
4
2
0
0
100
200 300
400
500
600
Load Resistor (W)
SF01153
NOTE:
When using open-collector parts, 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.
TEST CIRCUIT AND WAVEFORMS
V_CC
7.0V
90%
t_w
90%
AMP (V)
V_IN
V_OUT
R_L
PULSE
D.U.T.
GENERATOR
NEGATIVE
PULSE
V_M
10%
V_M
10%
0V
t_{THL (}t_f )
t_{TLH (}t_r )
R_T
C_L R_L
Test Circuit for Open Collector Outputs
POSITIVE
PULSE
t_{TLH (}t_r )
90%
V_M
t_{THL (}t_f )
90%
V_M
AMP (V)
DEFINITIONS:
R_L = Load resistor;
see AC electrical characteristics for value.
C_L = Load capacitance includes jig and probe capacitance;
see AC electrical characteristics for value.
R_T = Termination resistance should be equal to Z_OUT of
pulse generators.
10%
t_w
10%
0V
Input Pulse Definition
INPUT PULSE REQUIREMENTS
family
amplitude ^VM rep. rate
t_w
t_TLH
t_THL
74F
3.0V 1.5V 1MHz 500ns 2.5ns 2.5ns
SF00027
1996 Jan 05
6