CD54AC138_14 Datasheet, PDF (6/17 Pages) Texas Instruments – 3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS

CD54AC138, CD74AC138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SCHS328A – JANUARY 2003 – REVISED FEBRUARY 2003
PARAMETER MEASUREMENT INFORMATION
From Output
Under Test
CL = 50 pF
(see Note A)
R1 = 500 Ω^{† S1}
R2 = 500 Ω^†
2 × VCC
Open
GND
† _{When VCC = 1.5 V, R1 = R2 = 1 kΩ}
LOAD CIRCUIT
Input
TEST
tPLH/tPHL
tPLZ/tPZL
tPHZ/tPZH
S1
Open
2 × VCC
GND
tw
50% VCC
VCC
50% VCC
0V
VOLTAGE WAVEFORMS
PULSE DURATION
CLR
Input
CLK
50% VCC
trec
50% VCC
VOLTAGE WAVEFORMS
RECOVERY TIME
VCC
0V
VCC
0V
Reference
Input
50% VCC
VCC
0V
Data
Input
50%
10%
tsu
90%
tr
th
90%
VCC
5100%%VC0CV
tf
VOLTAGE WAVEFORMS
SETUP AND HOLD AND INPUT RISE AND FALL TIMES
Input
In-Phase
Output
Out-of-Phase
Output
50% VCC
tPLH
50%
10%
tPHL
90%
90%
50% VCC
tPHL
90%
tr
501%0%VCC
tf
tPLH
50%
10%
VCC
0V
VOH
5100%%VCVCOL
tf
90% ^VOH
VOL
tr
VOLTAGE WAVEFORMS
PROPAGATION DELAY AND OUTPUT TRANSITION TIMES
Output
Control
50% VCC
VCC
50% VCC
0V
tPZL
Output
Waveform 1
S1 at 2 × VCC
(see Note B)
Output
Waveform 2
S1 at GND
(see Note B)
tPZH
50% VCC
50% VCC
tPLZ
≈VCC
20% VCC
VOL
tPHZ
VOH
80% VCC
≈0 V
VOLTAGE WAVEFORMS
OUTPUT ENABLE AND DISABLE TIMES
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. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, ZO = 50 Ω, tr = 3 ns, tf = 3 ns.
Phase relationships between waveforms are arbitrary.
D. For clock inputs, fmax is measured with the input duty cycle at 50%.
E. The outputs are measured one at a time with one input transition per measurement.
F. tPLH and tPHL are the same as tpd.
G. tPZL and tPZH are the same as ten.
H. tPLZ and tPHZ are the same as tdis.
I. All parameters and waveforms are not applicable to all devices.
Figure 1. Load Circuit and Voltage Waveforms
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