Freelance Electronics Components Distributor
Closed Dec 25th-26th
800-300-1968
We Stock Hard to Find Parts

DM74ALS138N

Part # DM74ALS138N
Description IC DECODER/DEMUX 3-8LINE 16-DIP
Category IC
Availability In Stock
Qty 54
Qty Price
1 + $0.29435
Manufacturer Available Qty
National Semiconductor Corp
Date Code: 9642
  • Shipping Freelance Stock: 44
    Ships Immediately
National Semiconductor Corp
Date Code: 9042
  • Shipping Freelance Stock: 10
    Ships Immediately



Technical Document


DISCLAIMER: The information provided herein is solely for informational purposes. Customers must be aware of the suitability of this product for their application, and consider that variable factors such as Manufacturer, Product Category, Date Codes, Pictures and Descriptions may differ from available inventory.

© 2000 Fairchild Semiconductor Corporation DS006111 www.fairchildsemi.com
September 1986
Revised February 2000
DM74ALS138 3 to 8 Line Decoder/Demultiplexer
DM74ALS138
3 to 8 Line Decoder/Demultiplexer
General Description
These Schottky-clamped circuits are designed to be used
in high-performance memory-decoding or data-routing
applications, requiring very short propagation delay times.
In high-performance memory systems these decoders can
be used to minimize the effects of system decoding. When
used with high-speed memories, the delay times of these
decoders are usually less than the typical access time of
the memory. This means that the effective system delay
introduced by the decoder is negligible.
The DM74ALS138 decodes one-of-eight lines, based upon
the conditions at the three binary select inputs and the
three enable inputs. Two active-LOW and one active-HIGH
enable inputs reduce the need for external gates or invert-
ers when expanding. A 24-line decoder can be imple-
mented with no external inverters, and 32-line decoder
requires only one inverter. An enable input can be used as
a data input for demultiplexing applications.
This decoder/demultiplexer features fully buffered inputs,
presenting only one normalized load to its driving circuit. All
inputs are clamped with high-performance Schottky diodes
to suppress line-ringing and simplify system design.
Features
Designed specifically for high speed:
Memory decoders
Data transmission systems
3- to 8-line decoder incorporates 3 enable inputs to sim-
plify cascading and/or data reception
Low power dissipation…23 mW typ
Switching specifications guaranteed over full tempera-
ture and V
CC
range
Advanced oxide-isolated, ion-implanted Schottky TTL
process
Ordering Code:
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram Function Table
Note 1: G2 = G2A + G2B
Order Number Package Number Package Description
DM74ALS138M M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74ALS138SJ M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
DM74ALS138N N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Enable Select
Outputs
Inputs Inputs
G1 G
2
(Note 1)
C B A Y0Y1Y2Y3Y4Y5Y6Y7
X H XXXHHHHHHHH
L X XXXHHHHHHHH
H L LL LLHHHHHHH
H L LLHHLHHHHHH
H L LHLHHLHHHHH
H L LHHHHHLHHHH
H L HLLHHHHLHHH
H L HLHHHHHHLHH
H L HHLHHHHHHLH
H L HHHHHHHHHHL
www.fairchildsemi.com 2
DM74ALS138
Logic Diagram
3 www.fairchildsemi.com
DM74ALS138
Absolute Maximum Ratings(Note 2)
Note 2: The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Electrical Characteristics
over recommended operating free air temperature range. All typical values are measured at V
CC
= 5V, T
A
= 25°C.
Switching Characteristics
over recommended operating free air temperature range.
Supply Voltage 7V
Input Voltage 7V
Operating Free Air Temperature Range 0°C to +70°C
Storage Temperature Range 65°C to +150°C
Typical θ
JA
N Package 75.5°C/W
M Package 104.0°C/W
Symbol Parameter Min Nom Max Units
V
CC
Supply Voltage 4.5 5 5.5 V
V
IH
HIGH Level Input Voltage 2 V
V
IL
LOW Level Input Voltage 0.8 V
I
OH
HIGH Level Output Current 0.4 mA
I
OL
LOW Level Output Current 8 mA
T
A
Free Air Operating Temperature 0 70 °C
Symbol Parameter Conditions Min Typ Max Units
V
IK
Input Clamp Voltage V
CC
= 4.5V, I
I
= 18 mA 1.5 V
V
OH
HIGH Level I
OH
= 0.4 mA V
CC
2V
Output Voltage V
CC
= 4.5V to 5.5V
V
OL
LOW Level
V
CC
= 4.5V I
OL
= 8 mA 0.35 0.5 V
Output Voltage
I
I
Input Current @ Max.
V
CC
= 5.5V, V
IH
= 7V 0.1 mA
Input Voltage
I
IH
HIGH Level Input Current V
CC
= 5.5V, V
IH
= 2.7V 20 µA
I
IL
LOW Level Input Current V
CC
= 5.5V, V
IL
= 0.4V 0.1 mA
I
O
Output Drive Current V
CC
= 5.5V V
O
= 2.25V 30 112 mA
I
CC
Supply Current V
CC
= 5.5V 5 10 mA
Symbol Parameter Conditions
From (Input)
Min
Max
Units
To (Output)
t
PLH
Propagation Delay Time V
CC
= 4.5V to 5.5V A, B, C
622ns
LOW-to-HIGH Level Output R
L
= 500 to Y
t
PHL
Propagation Delay Time C
L
= 50 pF A, B, C
618ns
HIGH-to-LOW Level Output to Y
t
PLH
Propagation Delay Time Enable
417ns
LOW-to-HIGH Level Output to Y
t
PHL
Propagation Delay Time Enable
517ns
HIGH-to-LOW Level Output to Y
12NEXT