SN74ALS646 Datasheet, PDF (17/29 Pages) Texas Instruments – OCTAL BUS TRANSCEIVERS AND REGISTERS WITH 3-STATE OUTPUTS

From Output
Under Test
CL = 50 pF
(see Note A)
SN54ALS646, SN54ALS648, SN54AS646
SN74ALS646A, SN74ALS648A, SN74AS646, SN74AS648
OCTAL BUS TRANSCEIVERS AND REGISTERS WITH 3-STATE OUTPUTS
SDAS039F – DECEMBER 1983 – REVISED JANUARY 1995
PARAMETER MEASUREMENT INFORMATION
7V
Open
S1
R1 = 500 Ω
Test Point
R2 = 500 Ω
SWITCH POSITION TABLE
TEST
tPLH
tPHL
tPZH
tPZL
tPHZ
tPLZ
S1
Open
Open
Open
Closed
Open
Closed
VCC
From Output
Under Test
CL = 50 pF
(see Note A)
RL
Test Point
LOAD CIRCUIT
FOR 3-STATE OUTPUTS
LOAD CIRCUIT
FOR OPEN-COLLECTOR OUTPUTS
Timing
Input
tsu
Data
Input
1.3 V
th
1.3 V
1.3 V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
3.5 V
0.3 V
3.5 V
0.3 V
High-Level
Pulse
Low-Level
Pulse
1.3 V
tw
1.3 V
1.3 V
1.3 V
VOLTAGE WAVEFORMS
PULSE DURATION
3.5 V
0.3 V
3.5 V
0.3 V
Input
tPLH
In-Phase
Output
tPHL
Out-of-Phase
Output
1.3 V
1.3 V
1.3 V
1.3 V
3.5 V
0.3 V
tPHL
VOH
1.3 V
VOL
tPLH
VOH
1.3 V
VOL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
3.5 V
Output
Control
tPZL
1.3 V
1.3 V
tPLZ
0.3 V
3.5 V
Waveform 1
S1 Closed
(see Note B)
tPZH
Waveform 2
S1 Open
(see Note B)
1.3 V
tPHZ
1.3 V
VOL
0.3 V
VOH
0.3 V
0V
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS
NOTES: A. CL includes probe and jig 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. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, ZO = 50 Ω, tr ≤ 2 ns, tf ≤ 2 ns.
D. The outputs are measured one at a time with one transition per measurement.
Figure 2. Load Circuits and Voltage Waveforms
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