Page 1
74ALS138
1-of-8 decoder/demultiplexer
Product specification 1996 Jul 03
INTEGRATED CIRCUITS
IC05 Data Handbook
Page 2
Philips Semiconductors Product specification
74ALS1381-of-8 decoder/demultiplexer
2
1996 Jul 03 853–1848 17016
FEA TURES
•Demultiplexing capability
•Multiple input enable for easy expansion
•Ideal for memory chip select decoding
DESCRIPTION
The 74ALS138 decoder accepts three binary weighted inputs (A0,
A1, A2) and when enabled, provides eight mutually exclusive,
active-Low outputs (Q
0 – Q7). The device features three Enable
inputs; two active-Low (E
0, E1) and one active-High (E2). Every
output will be High unless E
0 and E1 are Low and E2 is High. This
multiple enable function allows easy parallel expansion of the device
to 1-of-32 (5 lines to 32 lines) decoder with just four 74ALS138s and
one inverter. The device can be used as an eight output
demultiplexer by using one of the active-Low Enable inputs as the
data input and the remaining Enable inputs as strobes. Enable
inputs not used must be permanently tied to their appropriate
active-High or active-Low state.
TYPE
TYPICAL
PROPAGATION DELAY
TYPICAL
SUPPLY CURRENT
(TOTAL)
74ALS138 12.0ns 4.0mA
PIN CONFIGURATION
16
15
14
13
12
11
107
6
5
4
3
2
1
Q
7
V
CC
Q3
Q4
Q5
Q
2
Q
0
Q
1
A0
A1
E2
A2
E
0
E
1
98GND Q6
SF00174
ORDERING INFORMA TION
ORDER CODE
DESCRIPTION COMMERCIAL RANGE
V
CC
= 5V ±10%,
T
amb
= 0°C to +70°C
DRAWING
NUMBER
16-pin plastic DIP 74ALS138N SOT38-4
16-pin plastic SO 74ALS138D SOT109-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS DESCRIPTION
74ALS (U.L.)
HIGH/LOW
LOAD VALUE
HIGH/LOW
A0 – A2 Address inputs 1.0/1.0 20µA/0.1mA
E0, E1 Enable inputs (active-Low) 1.0/1.0 20µA/0.1mA
E2 Enable input (active-High) 1.0/1.0 20µA/0.1mA
Q0 – Q7 Data outputs (active-Low) 50/33 1.0mA/20mA
NOTE: One (1.0) ALS unit load is defined as: 20µA in the High state and 0.1mA in the Low state.
LOGIC SYMBOL
A1 A2A0
Q2 Q3 Q4 Q5
13 12 11 10
123
VCC = Pin 16
GND = Pin 8
SF00175
Q114Q0
15
Q69Q7
7
4
5
6
E0
E1
E2
IEC/IEEE SYMBOL
SC00047
DX
1
2
4
5
6
15
14
13
12
11
10
9
7
0
0
1
2
G
0
7
3
3
2
&
Page 3
Philips Semiconductors Product specification
74ALS1381-of-8 decoder/demultiplexer
1996 Jul 03
3
LOGIC DIAGRAM
15 14 13 12 11 10 9 7
Q
0Q1Q2Q3Q4Q5Q6Q7
3
2
1
4
5
6
A2
A1
A0
E
0
E
1
E2
V
CC
= Pin 16
GND = Pin 8
SF00177
FUNCTION TABLE
INPUTS OUTPUTS
E0 E1 E2 A0 A1 A2 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7
H X X X X X H H H H H H H H
X H X X X X H H H H H H H H
X X L X X X H H H H H H H H
L L H L L L L H H H H H H H
L L H H L L H L H H H H H H
L L H L H L H H L H H H H H
L L H H H L H H H L H H H H
L L H L L H H H H H L H H H
L L H H L H H H H H H L H H
L L H L H H H H H H H H L H
L L H H H H H H H H H H H L
H = High voltage level
L = Low voltage level
X = Don’t care
Page 4
Philips Semiconductors Product specification
74ALS1381-of-8 decoder/demultiplexer
1996 Jul 03
4
ABSOLUTE MAXIMUM RATINGS
(Operation beyond the limit set forth in this table may impair the useful life of the device.
Unless otherwise noted these limits are over the operating free-air temperature range.)
SYMBOL
PARAMETER RATING UNIT
V
CC
Supply voltage –0.5 to +7.0 V
V
IN
Input voltage –0.5 to +7.0 V
I
IN
Input current –30 to +5 mA
V
OUT
Voltage applied to output in High output state –0.5 to V
CC
V
I
OUT
Current applied to output in Low output state 16 mA
T
amb
Operating free-air temperature range 0 to +70 °C
T
stg
Storage temperature range –65 to +150 °C
RECOMMENDED OPERATING CONDITIONS
LIMITS
SYMBOL
PARAMETER
MIN NOM MAX
UNIT
V
CC
Supply voltage 4.5 5.0 5.5 V
V
IH
High-level input voltage 2.0 V
V
IL
Low-level input voltage 0.8 V
I
Ik
Input clamp current –18 mA
I
OH
High-level output current –0.4 mA
I
OL
Low-level output current 8 mA
T
amb
Operating free-air temperature range 0 +70 °C
DC ELECTRICAL CHARACTERISTICS
(Over recommended operating free-air temperature range unless otherwise noted.)
LIMITS
SYMBOL
PARAMETER
TEST CONDITIONS
1
MIN TYP
2
MAX
UNIT
V
OH
High-level output voltage
VCC = ±10%, VIL = MAX,
V
IH
= MIN
IOH = –0.4mA V
CC
– 2 V
p
VCC = MIN, VIL = MAX,
I
OL
= 4mA 0.25 0.40 V
VOLLow-level output voltage
CC
,
IL
,
VIH = MIN
I
OL
= 8mA 0.35 0.50 V
V
IK
Input clamp voltage VCC = MIN, II = I
IK
–0.73 –1.5 V
I
I
Input current at maximum input
voltage
VCC = MAX, VI = 7.0V 0.1 mA
I
IH
High-level input current VCC = MAX, VI = 2.7V 20 µA
I
IL
Low-level input current VCC = MAX, VI = 0.4V –0.1 mA
I
O
Output current
3
VCC = MAX, VO = 2.25V –30 –112 mA
I
CC
Supply current (total) VCC = MAX 4 7 mA
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions for the applicable type.
2. All typical values are at V
CC
= 5V, T
amb
= 25°C.
3. The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, I
OS
.
Page 5
Philips Semiconductors Product specification
74ALS1381-of-8 decoder/demultiplexer
1996 Jul 03
5
AC ELECTRICAL CHARACTERISTICS
LIMITS
SYMBOL PARAMETER TEST CONDITION
T
amb
= 0°C to +70°C
V
CC
= +5.0V ± 10%
C
L
= 50pF, RL = 500Ω
UNIT
MIN MAX
t
PLH
t
PHL
Propagation delay
An
to Qn
Waveform 1, 2
3.0
3.0
22.0
18.0
ns
t
PLH
t
PHL
Propagation delay
E
1, E2 to Qn
Waveform 2
3.0
3.0
17.0
17.0
ns
t
PLH
t
PHL
Propagation delay
E2
to Qn
Waveform 1
3.0
3.0
17.0
17.0
ns
AC WAVEFORMS
For all waveforms, VM = 1.3V .
V
M
V
M
V
M
V
M
Qn
An, E2
t
PHL
t
PLH
SF00179
Waveform 1. Propagation Delay for Inverting Outputs
V
M
V
M
V
M
V
M
Qn
An, E
0, E1
t
PHL
t
PLH
SF00180
Waveform 2. Propagation Delay for Non-inverting Outputs
TEST CIRCUIT AND WAVEFORMS
t
w
90%
V
M
10%
90%
V
M
10%
90%
V
M
10%
90%
V
M
10%
NEGATIVE
PULSE
POSITIVE
PULSE
t
w
AMP (V)
0.3V
0.3V
t
THL (tf
f
)
INPUT PULSE REQUIREMENTS
Rep.Rate
t
w
t
TLHtTHL
1MHz
500ns
2.0ns 2.0ns
Input Pulse Definition
V
CC
Family
74ALS
D.U.T.
PULSE
GENERATOR
R
L
C
L
R
T
V
IN
V
OUT
Test Circuit for Totem-pole Outputs
DEFINITIONS:
R
L
= Load resistor;
see AC electrical characteristics for value.
CL= Load capacitance includes jig and probe capacitance;
see AC electrical characteristics for value.
R
T
= Termination resistance should be equal to Z
OUT
of
pulse generators.
t
THL (tf
)
t
TLH (tr
)
t
TLH (tr
)
AMP (V)
Amplitude
3.5V
1.3V
V
M
SC00005
Page 6
Philips Semiconductors Product specification
74ALS1381-of-8 decoder/demultiplexer
1996 Jul 03
6
DIP16: plastic dual in-line package; 16 leads (300 mil) SOT38-4
Page 7
Philips Semiconductors Product specification
74ALS1381-of-8 decoder/demultiplexer
1996 Jul 03
7
SO16: plastic small outline package; 16 leads; body width 3.9 mm SOT109-1
Page 8
Philips Semiconductors Product specification
74ALS1381-of-8 decoder/demultiplexer
1996 Jul 03
8
Philips Semiconductors and Philips Electronics North America Corporation reserve the right to make changes, without notice, in the products,
including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips
Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright,
or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask
work right infringement, unless otherwise specified. Applications that are described herein for any of these products are for illustrative purposes
only. Philips Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing
or modification.
LIFE SUPPORT APPLICA TIONS
Philips Semiconductors and Philips Electronics North America Corporation Products are not designed for use in life support appliances, devices,
or systems where malfunction of a Philips Semiconductors and Philips Electronics North America Corporation Product can reasonably be expected
to result in a personal injury. Philips Semiconductors and Philips Electronics North America Corporation customers using or selling Philips
Semiconductors and Philips Electronics North America Corporation Products for use in such applications do so at their own risk and agree to fully
indemnify Philips Semiconductors and Philips Electronics North America Corporation for any damages resulting from such improper use or sale.
This data sheet contains preliminary data, and supplementary data will be published at a later date. Philips
Semiconductors reserves the right to make changes at any time without notice in order to improve design
and supply the best possible product.
Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 94088–3409
Telephone 800-234-7381
DEFINITIONS
Data Sheet Identification Product Status Definition
Objective Specification
Preliminary Specification
Product Specification
Formative or in Design
Preproduction Product
Full Production
This data sheet contains the design target or goal specifications for product development. Specifications
may change in any manner without notice.
This data sheet contains Final Specifications. Philips Semiconductors reserves the right to make changes
at any time without notice, in order to improve design and supply the best possible product.
Copyright Philips Electronics North America Corporation 1997
All rights reserved. Printed in U.S.A.
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