SN54AHCT138 Datasheet, PDF (6/9 Pages) Texas Instruments – 3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS

SN54AHCT138, SN74AHCT138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SCLS266J – DECEMBER 1995 – REVISED JANUARY 2000
PARAMETER MEASUREMENT INFORMATION
From Output
Under Test
CL
(see Note A)
Test
Point
From Output
Under Test
CL
(see Note A)
RL = 1 kΩ ^S1
VCC
Open
GND
TEST
tPLH/tPHL
tPLZ/tPZL
tPHZ/tPZH
Open Drain
S1
Open
VCC
GND
VCC
LOAD CIRCUIT FOR
TOTEM-POLE OUTPUTS
LOAD CIRCUIT FOR
3-STATE AND OPEN-DRAIN OUTPUTS
Input
tw
3V
1.5 V
1.5 V
0V
VOLTAGE WAVEFORMS
PULSE DURATION
3V
Timing Input
1.5 V
0V
th
tsu
3V
Data Input
1.5 V
1.5 V
0V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
Input
1.5 V
3V
1.5 V
0V
tPLH
In-Phase
Output
50% VCC
tPHL
VOH
50% VCC
VOL
tPHL
tPLH
Out-of-Phase
Output
50% VCC
VOH
50% VCC
VOL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
INVERTING AND NONINVERTING OUTPUTS
Output
Control
1.5 V
3V
1.5 V
0V
tPZL
Output
Waveform 1
S1 at VCC
(see Note B)
tPZH
Output
Waveform 2
S1 at GND
(see Note B)
50% VCC
50% VCC
tPLZ
≈VCC
VOL + 0.3 V _VOL
tPHZ
VOH – 0.3 VVOH
≈0 V
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES
LOW- AND HIGH-LEVEL ENABLING
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 ≤ 3 ns, tf ≤ 3 ns.
D. The outputs are measured one at a time with one input transition per measurement.
Figure 1. Load Circuit and Voltage Waveforms
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