SN54HCT240_16 Datasheet, PDF (5/20 Pages) Texas Instruments – OCTAL BUFFERS AND LINE DRIVERS WITH 3-STATE OUTPUTS

SN54HCT240, SN74HCT240
OCTAL BUFFERS AND LINE DRIVERS
WITH 3ĆSTATE OUTPUTS
SCLS174E − MARCH 1984 − REVISED AUGUST 2003
PARAMETER MEASUREMENT INFORMATION
Test
From Output ^{Point RL}
Under Test
CL
(see Note A)
VCC
S1
S2
LOAD CIRCUIT
PARAMETER RL
tPZH
ten
1 kΩ
tPZL
tPHZ
tdis
1 kΩ
tPLZ
tpd or tt
−−
CL
50 pF
or
150 pF
S1
Open
Closed
Open
50 pF
Closed
50 pF
or
150 pF
Open
S2
Closed
Open
Closed
Open
Open
Input _{1.3 V}
0.3 V
2.7 V
tr
2.7 V
3V
1.3 V
0.3 V _{0 V}
tf
VOLTAGE WAVEFORM
INPUT RISE AND FALL TIMES
Input
In-Phase
Output
Out-of-
Phase
Output
1.3 V
tPLH
1.3 V
10%
tPHL
90%
90%
tr
1.3 V
10%
tf
1.3 V
tPHL
90%
tPLH
1.3 V
10%
3V
0V
VOH
1.3 V
10% _VOL
tf
90% ^VOH
VOL
tr
VOLTAGE WAVEFORMS
PROPAGATION DELAY AND OUTPUT RISE AND FALL TIMES
Output
Control
(Low-Level
Enabling)
tPZL
Output
Waveform 1
(See Note B)
tPZH
Output
Waveform 2
(See Note B)
1.3 V
1.3 V
1.3 V
1.3 V
3V
tPLZ
0V
≈VCC
10% _VOL
tPHZ
90% ^VOH
≈0 V
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES FOR 3-STATE OUTPUTS
NOTES: A. CL 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, ZO = 50 Ω, tr = 6 ns, tf = 6 ns.
D. The outputs are measured one at a time with one input transition per measurement.
E. tPLZ and tPHZ are the same as tdis.
F. tPZL and tPZH are the same as ten.
G. tPLH and tPHL are the same as tpd.
Figure 1. Load Circuit and Voltage Waveforms
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