SN54LS240, SN54LS241, SN54LS244, SN54S240, SN54S241, SN54S244
SN74LS240, SN74LS241, SN74LS244, SN74S240, SN74S241, SN74S244
OCTAL BUFFERS AND LINE DRIVERS WITH 3-STATE OUTPUTS
SDLS144B – APRIL 1985 – REVISED FEBRUARY 2002
PARAMETER MEASUREMENT INFORMATION
SERIES 54LS/74LS DEVICES
V
CC
Test
Point
R
L
Test
Point
S1
V
CC
From Output
Under Test
V
CC
(see Note B)
R
L
C
L
(see Note A)
From Output
Under Test
5 kΩ
R
L
(see Note B)
From Output
Under Test
C
Test
Point
C
L
(see Note A)
L
(see Note A)
S2
LOAD CIRCUIT
LOAD CIRCUIT
LOAD CIRCUIT
FOR 2-STATE TOTEM-POLE OUTPUTS
FOR OPEN-COLLECTOR OUTPUTS
FOR 3-STATE OUTPUTS
3 V
High-Level
Timing
Input
1.3 V
1.3 V
1.3 V
1.3 V
Pulse
0 V
t
t
h
w
t
su
3 V
0 V
Low-Level
Pulse
Data
Input
1.3 V
1.3 V
1.3 V
VOLTAGE WAVEFORMS
PULSE DURATIONS
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
Output
3 V
0 V
Control
(low-level
enabling)
1.3 V
1.3 V
3 V
0 V
Input
1.3 V
1.3 V
t
t
PLZ
PZL
t
t
PHL
PLH
Waveform 1
(see Notes C
and D)
≈1.5 V
In-Phase
Output
(see Note D)
1.3 V
V
V
OH
V
OL
+ 0.3 V
1.3 V
1.3 V
1.3 V
V
OL
t
PHZ
OL
t
PZH
t
t
PLH
PHL
V
OH
Waveform 2
(see Notes C
and D)
V
OH
– 0.3 V
Out-of-Phase
Output
(see Note D)
V
V
OH
1.3 V
1.3 V
≈1.5 V
OL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS
NOTES: A.
C
includes probe and jig capacitance.
L
B. All diodes are 1N3064 or equivalent.
C. 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.
D. S1 and S2 are closed for t
, t
, t
, and t
; S1 is open and S2 is closed for t
PLZ PZH
; S1 is closed and S2 is open for t .
PLH PHL PHZ
PZL
E. Phase relationships between inputs and outputs have been chosen arbitrarily for these examples.
F. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, Z ≈ 50 Ω, t ≤ 15 ns, t ≤ 6 ns.
O
r
f
G. The outputs are measured one at a time with one input transition per measurement.
Figure 1. Load Circuits and Voltage Waveforms
10
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TI [ TEXAS INSTRUMENTS ]
