SDFS066A − MARCH 1987 − REVISED OCTOBER 1993
Copyright 1993, Texas Instruments Incorporated
2−1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251−1443
•3-State Versions of SN54F151B and
SN74F151B
•3-State Outputs Interface Directly With
System Bus
•Performs Parallel-to-Serial Conversion
•Complementary Outputs Provide True and
Inverted Data
•Package Options Include Plastic
Small-Outline Packages, Ceramic Chip
Carriers, and Standard Plastic and Ceramic
300-mil DIPs
description
These data selectors/multiplexers contain full
binary decoding to select one of eight data
sources and feature strobe-controlled
complementary outputs. The 3-state outputs can
interface with and drive data lines of bus-
organized systems. When the strobe (G) input is
high, both outputs are in a high-impedance state
in which both the upper and lower transistors of
each totem-pole output are off, and the output
neither drives nor loads the bus significantly.
The SN54F251B is characterized for operation
over the full military temperature range of −55°C
to 125°C. The SN74F251B is characterized for
operation from 0°C to 70°C.
FUNCTION TABLE
INPUTS
OUTPUTS
SELECT
STROBE
OUTPUTS
C B A
STROBE
GY W
X X X H Z Z
LLL L D0 D0
LLH L D1 D1
LHL L D2 D2
LHH L D3 D3
HLL L D4 D4
HLH L D5 D5
HHL L D6 D6
H H H L D7 D7
D0, D1, . . . D7 = the level of the respective D input.
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
D3
D2
D1
D0
Y
W
G
GND
VCC
D4
D5
D6
D7
A
B
C
SN54F251B ...J PACKAGE
SN74F251B ...D OR N PACKAGE
(TOP VIEW)
3212019
910111213
4
5
6
7
8
18
17
16
15
14
D5
D6
NC
D7
A
D1
D0
NC
Y
W
SN54F251B . . . FK PACKAGE
(TOP VIEW)
D2
D3
NC
C
BD4
G
GND
NC
NC − No internal connection
VCC
!"#$%&'#! ( )*$$+!' &( #" ,*-.)&'#! /&'+0
$#/*)'( )#!"#$% '# (,+)")&'#!( ,+$ '1+ '+$%( #" +2&( !('$*%+!'(
('&!/&$/ 3&$$&!'40 $#/*)'#! ,$#)+((!5 /#+( !#' !+)+((&$.4 !).*/+
'+('!5 #" &.. ,&$&%+'+$(0
SDFS066A − MARCH 1987 − REVISED OCTOBER 1993
2−2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251−1443
logic symbol†
MUX
EN
7
0
11
A10
B
2
9
C
0
4
D0
1
3
D1
2
2
D2
3
1
D3
4
15
D4
5
14
D5
6
13
D6
7
12
D7
0
7
G
W
6Y
5
G
†This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the D, J, and N packages.
SDFS066A − MARCH 1987 − REVISED OCTOBER 1993
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POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251−1443
logic diagram (positive logic)
Data
Select
(Binary)
Data
Inputs
D0
D1
D2
D3
D4
D5
D6
D7
G
W
Y
C
A
B
7
4
3
2
1
15
14
13
12
11
10
9
5
6
Pin numbers shown are for the D, J, and N packages.
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Supply voltage range, VCC −0.5 V to 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range (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 disabled or power-off state −0.5 V to 5.5 V. . . . . . . . . . . . . . . . . . .
Voltage range applied to any output in the high state −0.5 V to VCC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current into any output in the low state: SN54F251B 40 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SN74F251B 48 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range: SN54F251B −55°C to 125°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SN74F251B 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.
SDFS066A − MARCH 1987 − REVISED OCTOBER 1993
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POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251−1443
recommended operating conditions
SN54F251B SN74F251B
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 −3 −3 mA
IOL Low-level output current 20 24 mA
TAOperating free-air temperature −55 125 0 70 °C
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
SN54F251B SN74F251B
UNIT
PARAMETER
TEST CONDITIONS
MIN TYP†MAX MIN TYP†MAX
UNIT
VIK VCC = 4.5 V, II = −18 mA −1.2 −1.2 V
VCC = 4.5 V
IOH = − 1 mA 2.5 3.4 2.5 3.4
VOH VCC = 4.5 V IOH = − 3 mA 2.4 3.3 2.4 3.3 V
VCC = 4.75 V, IOH = − 1 mA to −3 mA 2.7
VOL
VCC = 4.5 V
IOL = 20 mA 0.3 0.5
V
VOL VCC = 4.5 V IOL = 24 mA 0.35 0.5 V
IOZH VCC = 5.5 V, VO = 2.7 V 50 50 µA
IOZL VCC = 5.5 V, VO = 0.5 V −50 −50 µA
IIVCC = 5.5 V, VI = 7 V 0.1 0.1 mA
IIH VCC = 5.5 V, VI = 2.7 V 20 20 µA
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,
Condition A 15 22 15 22
mA
I
CC
VCC = 5.5 V,
See Note 2 Condition B 16 24 16 24
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 the outputs open under the following conditions:
A. Select input and data input at 4.5 V, output control grounded
B. All inputs at 4.5 V
SDFS066A − MARCH 1987 − REVISED OCTOBER 1993
2−5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251−1443
switching characteristics (see Note 3)
PARAMETER FROM
(INPUT) TO
(OUTPUT)
VCC = 5 V,
CL = 50 pF,
R1 = 500 Ω,
R2 = 500 Ω,
TA = 25°C
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
R1 = 500Ω,
R2 = 500 Ω,
TA = MIN to MAX†UNIT
′F251B SN54F251B SN74F251B
MIN TYP MAX MIN MAX MIN MAX
tPLH
A, B, or C
W
3.5 5.4 9 3.5 11.5 3.5 9.5
ns
tPHL A, B, or C W2.5 4.4 7.5 2.5 8 2.5 7.5 ns
tPLH
A, B, or C
Y
4.5 6.2 10.5 3.5 14 4 12.5
ns
tPHL A, B, or C Y4 6 8.5 3 10.9 3.5 9 ns
tPLH
Any D
W
2.5 3.7 6.5 1.8 8 2 7
ns
tPHL Any D W1 1.9 4 1 6 1 5 ns
tPLH
Any D
Y
3 3.8 7 2.3 9 2.3 8
ns
tPHL Any D Y3 4.5 7 2.3 9 2.5 8 ns
tPZH
G
W
2.5 3.6 6 2 7 2 7
ns
tPZL
G
W2.5 3.8 6 2.5 7.5 2.5 6.5 ns
tPHZ
G
W
1.9 2.5 5.5 1.4 6 1.5 6
ns
tPLZ
G
W1 2.4 4.5 1 5 1 4.5 ns
tPZH
G
Y
3.4 4.8 7 2.7 8.5 2.9 8.5
ns
tPZL
G
Y2.9 4 7.5 2.6 9 2.6 8 ns
tPHZ
G
Y
1.9 2.5 5.5 1.7 5.5 1.8 5.5
ns
tPLZ
G
Y
1 2.3 4.5 1 5.5 1 4.5
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.
SDFS066A − MARCH 1987 − REVISED OCTOBER 1993
2−6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251−1443
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