SN54F138, SN74F138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SDFS051B MARCH 1987 REVISED JULY 1996
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
D
Designed Specifically for High-Speed
Memory Decoders and Data Transmission
Systems
D
Incorporates Three Enable Inputs to
Simplify Cascading and/or Data Reception
D
Package Options Include Plastic
Small-Outline Packages, Ceramic Chip
Carriers, and Standard Plastic and Ceramic
300-mil DIPs
description
The
F138 is 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
employed with high-speed memories utilizing a
fast enable circuit, the delay times of this decoder
and the enable time of the memory 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 conditions at the binary-select inputs and the
three enable inputs select one of eight output
lines. Two active-low and one active-high enable
inputs reduce the need for external gates or
inverters when expanding. A 24-line decoder can
be implemented without external inverters and a 32-line decoder requires only one inverter. An enable input can
be used as a data input for demultiplexing applications.
The SN54F138 is characterized for operation over the full military temperature range of 55
C to 125
C. The
SN74F138 is characterized for operation from 0
C to 70
C.
Copyright
1996, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
SN54F138 . . . J PACKAGE
SN74F138 . . . D OR N PACKAGE
(TOP VIEW)
SN54F138 . . . FK PACKAGE
(TOP VIEW)
3
2
1 20 19
9 10 11 12 13
4
5
6
7
8
18
17
16
15
14
Y1
Y2
NC
Y3
Y4
C
G2A
NC
G2B
G1
B
A
NC
Y6
Y5
V
Y0
Y7
GND
NC
CC
NC No internal connection
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
A
B
C
G2A
G2B
G1
Y7
GND
V
CC
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SN54F138, SN74F138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SDFS051B MARCH 1987 REVISED JULY 1996
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
FUNCTION TABLE
ENABLE INPUTS
SELECT INPUTS
OUTPUTS
G1
G2A
G2B
C
B
A
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
X
H
X
X
X
X
H
H
H
H
H
H
H
H
X
X
H
X
X
X
H
H
H
H
H
H
H
H
L
X
X
X
X
X
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
H
H
L
H
H
H
H
H
H
H
L
L
L
H
L
H
H
L
H
H
H
H
H
H
L
L
L
H
H
H
H
H
L
H
H
H
H
H
L
L
H
L
L
H
H
H
H
L
H
H
H
H
L
L
H
L
H
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
H
H
H
H
H
H
H
H
H
L
logic symbols (alternatives)
BIN/OCT
1
1
A
2
2
B
4
3
C
4
5
6
G1
Y0
15
0
&
EN
Y1
14
1
Y2
13
2
Y3
12
3
Y4
11
4
Y5
10
5
Y6
9
6
Y7
7
7
DMUX
0
1
A
2
B
2
3
C
4
5
6
G1
Y0
15
0
&
Y1
14
1
Y2
13
2
Y3
12
3
Y4
11
4
Y5
10
5
Y6
9
6
Y7
7
7
G
7
0
G2A
G2B
G2A
G2B
These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
SN54F138, SN74F138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SDFS051B MARCH 1987 REVISED JULY 1996
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
logic diagram (positive logic)
G2B
G2A
G1
C
B
A
Y7
Y6
Y5
Y4
Y3
Y2
Y1
Y0
Data
Outputs
Select
Inputs
Enable
Inputs
1
2
3
6
4
5
15
14
13
12
11
10
9
7
Pin numbers shown are for the D, J, and N packages.
SN54F138, SN74F138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SDFS051B MARCH 1987 REVISED JULY 1996
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage range, V
CC
0.5 V to 7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range, V
I
(see Note 1)
1.2 V to 7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input current range
30 mA to 5 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Voltage range applied to any output in the high state
0.5 V to V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current into any output in the low state
40 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range: SN54F138
55
C to 125
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SN74F138
0
C to 70
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range
65
C to 150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only and
functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTE 1: The input voltage ratings may be exceeded provided the input current ratings are observed.
recommended operating conditions
SN54F138
SN74F138
UNIT
MIN
NOM
MAX
MIN
NOM
MAX
UNIT
VCC
Supply voltage
4.5
5
5.5
4.5
5
5.5
V
VIH
High-level input voltage
2
2
V
VIL
Low-level input voltage
0.8
0.8
V
IIK
Input clamp current
18
18
mA
IOH
High-level output current
1
1
mA
IOL
Low-level output current
20
20
mA
TA
Operating free-air temperature
55
125
0
70
C
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
SN54F138
SN74F138
UNIT
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNIT
VIK
VCC = 4.5 V,
II = 18 mA
1.2
1.2
V
VOH
VCC = 4.5 V,
IOH = 1 mA
2.5
3.4
2.5
3.4
V
VOH
VCC = 4.75 V,
IOH = 1 mA
2.7
V
VOL
VCC = 4.5 V,
IOL = 20 mA
0.3
0.5
0.3
0.5
V
II
VCC = 5.5 V,
VI = 7 V
0.1
0.1
mA
IIH
VCC = 5.5 V,
VI = 2.7 V
20
20
A
IIL
VCC = 5.5 V,
VI = 0.5 V
0.6
0.6
mA
IOS
VCC = 5.5 V,
VO = 0
60
150
60
150
mA
ICC
VCC = 5.5 V,
See Note 2
13
20
13
20
mA
All typical values are at VCC = 5 V, TA = 25
C.
Not more than one output should be shorted at a time, and the duration of the short circuit should not exceed one second.
NOTE 2: ICC is measured with outputs enabled and open.
SN54F138, SN74F138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SDFS051B MARCH 1987 REVISED JULY 1996
5
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
switching characteristics (see Note 3)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC = 5 V,
CL = 50 PF,
RL = 500
,
TA = 25
C
VCC = 4.5 V TO 5.5 V,
CL = 50 PF,
RL = 500
,
TA = MIN TO MAX
UNIT
(INPUT)
(OUTPUT)
F138
SN54F138
SN74F138
MIN
TYP
MAX
MIN
MAX
MIN
MAX
tPLH
A B or C
Y
2.7
5.2
7.5
2.7
12
2.7
8.5
ns
tPHL
A, B, or C
Y
3.2
5.7
8
3.2
9.5
3.2
9
ns
tPLH
G2A or G2B
Y
2.7
5
7
2.7
11
2.7
8
ns
tPHL
G2A or G2B
Y
2.2
4.9
7
2.2
8
2.2
7.5
ns
tPLH
G1
Y
3.2
5.8
8
3.2
12.5
3.2
9
ns
tPHL
G1
Y
2.7
5.2
7.5
2.7
8.5
2.7
8.5
ns
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
NOTE 3: Load circuits and waveforms are shown in Section 1.
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