TI SN74HCT138N

SN54HCT138, SN74HCT138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SCLS171C – MARCH 1984 – REVISED MAY 1997
D
SN54HCT138 . . . J OR W PACKAGE
SN74HCT138 . . . D, N, OR PW PACKAGE
(TOP VIEW)
A
B
C
G2A
G2B
G1
Y7
GND
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
VCC
Y0
Y1
Y2
Y3
Y4
Y5
Y6
SN54HCT138 . . . FK PACKAGE
(TOP VIEW)
description
The ’HCT138 are designed for high-performance
memory-decoding or data-routing applications
requiring very short propagation delay times. In
high-performance memory systems, these
decoders can minimize the effects of system
decoding. When employed with high-speed
memories utilizing a fast enable circuit, the delay
times of these decoders 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 decoders is
negligible.
B
A
NC
VCC
Y0
D
Inputs Are TTL-Voltage Compatible
Designed Specifically for High-Speed
Memory Decoders and Data Transmission
Systems
Incorporate Three Enable Inputs to Simplify
Cascading and/or Data Reception
Package Options Include Plastic
Small-Outline (D), Thin Shrink
Small-Outline (PW), and Ceramic Flat (W)
Packages, Ceramic Chip Carriers (FK), and
Standard Plastic (N) and Ceramic (J)
300-mil DIPs
C
G2A
NC
G2B
G1
4
3 2 1 20 19
18
5
17
6
16
7
15
8
14
9 10 11 12 13
Y1
Y2
NC
Y3
Y4
Y7
GND
NC
Y6
Y5
D
D
NC – No internal connection
The conditions at the binary-select inputs and the three enable inputs select one of eight output lines. Two
active-low (G) and one active-high (G) 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 SN54HCT138 is characterized for operation over the full military temperature range of –55°C to 125°C. The
SN74HCT138 is characterized for operation from –40°C to 85°C.
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.
Copyright  1997, 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.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
1
SN54HCT138, SN74HCT138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SCLS171C – MARCH 1984 – REVISED MAY 1997
FUNCTION TABLE
INPUTS
ENABLE
OUTPUTS
SELECT
G1
G2A
G2B
C
B
A
Y0
Y1
Y2
Y3
Y4
Y5
Y6
X
H
X
X
X
X
H
H
H
H
H
H
H
Y7
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)†
A
B
C
G1
G2A
G2B
1
2
3
6
4
5
BIN/OCT
0
1
1
2
2
4
3
4
&
EN
5
6
7
15
14
13
12
11
10
9
7
Y0
A
Y1
Y2
Y3
B
C
G1
Y6
G2A
Y7
G2B
POST OFFICE BOX 655303
0
2
3
6
4
5
† These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the D, J, N, PW, and W packages.
2
DMUX
0
G
2
0
7
1
2
3
Y4
Y5
1
• DALLAS, TEXAS 75265
&
4
5
6
7
15
14
13
12
11
10
9
7
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
SN54HCT138, SN74HCT138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SCLS171C – MARCH 1984 – REVISED MAY 1997
logic diagram (positive logic)
15
A
B
C
1
14
Y1
2
13
3
12
11
10
G1
Y0
6
Y2
Y3
Y4
Y5
9
Y6
G2A
4
7
G2B
Y7
5
Pin numbers shown are for the D, J, N, PW, and W packages.
absolute maximum ratings over operating free-air temperature range†
Supply voltage range, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Input clamp current, IIK (VI < 0 or VI > VCC) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA
Output clamp current, IOK (VO < 0 or VO > VCC) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA
Continuous output current, IO (VO = 0 to VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±25 mA
Continuous current through VCC or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
Package thermal impedance, θJA (see Note 2): D package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113°C/W
N package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78°C/W
Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –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.
NOTES: 1. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
2. The package thermal impedance is calculated in accordance with JESD 51, except for through-hole packages, which use a trace
length of zero.
POST OFFICE BOX 655303
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3
SN54HCT138, SN74HCT138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SCLS171C – MARCH 1984 – REVISED MAY 1997
recommended operating conditions
SN54HCT138
SN74HCT138
MIN
NOM
MAX
MIN
NOM
MAX
4.5
5
5.5
4.5
5
5.5
UNIT
VCC
VIH
Supply voltage
VIL
VI
Low-level input voltage
0
0.8
0
0.8
V
Input voltage
0
0
Output voltage
0
0
VCC
VCC
V
VO
tt
VCC
VCC
0
500
0
500
ns
TA
Operating free-air temperature
–55
125
–40
85
°C
High-level input voltage
VCC = 4.5 V to 5.5 V
VCC = 4.5 V to 5.5 V
2
Input transition (rise and fall) time
2
V
V
V
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
VCC
VOH
VI = VIH or VIL
IOH = –20 µA
IOH = –4 mA
45V
4.5
VOL
VI = VIH or VIL
IOL = 20 µA
IOL = 4 mA
45V
4.5
II
ICC
VI = VCC or 0
VI = VCC or 0,
∆ICC†
MIN
MIN
MAX
SN74HCT138
MIN
4.4
4.499
4.4
4.4
4.3
3.7
3.84
5.5 V
4.5 V
to 5.5 V
MAX
UNIT
V
0.001
0.1
0.1
0.1
0.17
0.26
0.4
0.33
±0.1
±100
±1000
±1000
nA
8
160
80
µA
1.4
2.4
3
2.9
mA
3
10
10
10
pF
5.5 V
Ci
SN54HCT138
3.98
5.5 V
IO = 0
One input at 0.5 V or 2.4 V,
Other inputs at 0 or VCC
TA = 25°C
TYP
MAX
V
† This is the increase in supply current for each input that is at one of the specified TTL voltage levels rather than 0 V or VCC.
switching characteristics over recommended operating free-air temperature range, CL = 50 pF
(unless otherwise noted) (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
A B,
A,
B or C
Any Y
tpd
d
Enable
tt
Any Y
Y
VCC
MIN
TA = 25°C
TYP
MAX
SN54HCT138
MIN
MAX
SN74HCT138
MIN
MAX
4.5 V
23
36
54
45
5.5 V
17
32
49
34
4.5 V
22
33
50
42
5.5 V
18
30
45
38
4.5 V
12
15
22
19
5.5 V
11
14
20
17
UNIT
ns
ns
operating characteristics, TA = 25°C
PARAMETER
Cpd
4
TEST CONDITIONS
Power dissipation capacitance
No load
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
TYP
85
UNIT
pF
SN54HCT138, SN74HCT138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SCLS171C – MARCH 1984 – REVISED MAY 1997
PARAMETER MEASUREMENT INFORMATION
From Output
Under Test
3V
Test
Point
Input
1.3 V
1.3 V
0V
CL = 50 pF
(see Note A)
tPLH
In-Phase
Output
LOAD CIRCUIT
1.3 V
10%
tPHL
90%
90%
tr
Input 1.3 V
0.3 V
2.7 V
2.7 V
tr
tPHL
3V
1.3 V
0.3 V 0 V
Out-of-Phase
Output
90%
tf
VOLTAGE WAVEFORM
INPUT RISE AND FALL TIMES
VOH
1.3 V
10% V
OL
tf
tPLH
1.3 V
10%
tf
1.3 V
10%
90%
VOH
VOL
tr
VOLTAGE WAVEFORMS
PROPAGATION DELAY AND OUTPUT RISE AND FALL TIMES
NOTES: A. CL includes probe and test-fixture capacitance.
B. Phase relationships between waveforms were chosen arbitrarily. All input pulses are supplied by generators having the following
characteristics: PRR ≤ 1 MHz, ZO = 50 Ω, tr = 6 ns, tf = 6 ns.
C. The outputs are measured one at a time with one input transition per measurement.
D. tPLH and tPHL are the same as tpd.
Figure 1. Load Circuit and Voltage Waveforms
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
5
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Copyright  1998, Texas Instruments Incorporated