SN54HC245, SN74HC245
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SCLS131D − DECEMBER 1982 − REVISED AUGUST 2003
PARAMETER MEASUREMENT INFORMATION
V
CC
PARAMETER
Test
Point
S1
R
L
t
en
t
PZH
1 kΩ
t
PZL
t
PHZ
t
PLZ
1 kΩ
R
L
C
L
50 pF
or
150 pF
50 pF
50 pF
or
150 pF
S1
Open
Closed
Open
Closed
−−
Open
S2
Closed
Open
Closed
Open
Open
From Output
Under Test
C
L
(see Note A)
S2
t
dis
t
pd
or t
t
LOAD CIRCUIT
V
CC
Input
50%
t
PLH
In-Phase
Output
50%
10%
t
PHL
Out-of-Phase
Output
90%
50%
10%
t
f
90%
t
r
t
PLH
50%
10%
90%
t
r
V
OH
V
OL
Output
Waveform 1
(See Note B)
t
PZH
Input
50%
10%
90%
90%
V
CC
50%
10% 0 V
t
f
Output
Waveform 2
(See Note B)
50%
0V
t
PHL
90%
V
OH
50%
10% V
OL
t
f
Output
Control
(Low-Level
Enabling)
t
PZL
V
CC
50%
50%
0V
t
PLZ
≈V
CC
50%
10%
t
PHZ
50%
90%
V
OH
≈0
V
≈V
CC
V
OL
VOLTAGE WAVEFORMS
PROPAGATION DELAY AND OUTPUT TRANSITION TIMES
t
r
VOLTAGE WAVEFORM
INPUT RISE AND FALL TIMES
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES FOR 3-STATE OUTPUTS
NOTES: A. C
L
includes probe and test-fixture capacitance.
B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.
C. Phase relationships between waveforms were chosen arbitrarily. All input pulses are supplied by generators having the following
characteristics: PRR
≤
1 MHz, Z
O
= 50
Ω,
t
r
= 6 ns, t
f
= 6 ns.
D. The outputs are measured one at a time with one input transition per measurement.
E. t
PLZ
and t
PHZ
are the same as t
dis
.
F. t
PZL
and t
PZH
are the same as t
en
.
G. t
PLH
and t
PHL
are the same as t
pd
.
Figure 1. Load Circuit and Voltage Waveforms
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
5
TI [ TEXAS INSTRUMENTS ]
