Philips Semiconductors
Product specification
8-input multiplexer (3-State)
74F251A
FEATURES
•
High speed 8-to-1 multiplexing
•
On chip decoding
•
Multifunction capability
•
Inverting and Non-Inverting outputs
•
Both outputs are 3-State for further multiplexer expansion
DESCRIPTION
The 74F251A is a logic implementation of a single 8-position switch
with the switch position controlled by the state of three Select (S0,
S1, S2) inputs. True (Y) and complementary (Y) outputs are both
provided. The output enable (OE) is active Low. When OE is High,
both outputs are in High impedance state, allowing multiple output
connections to a common bus without driving nor loading the bus
significantly. All but one device must be in High impedance state to
avoid high currents that would exceed the maximum ratings when
the outputs of the 3-State devices are tied together. When the output
of more than one device is tied together the user must ensure that
there is no overlap in the active Low portion of the output enable
voltages.
PIN CONFIGURATION
I3
I2
I1
I0
Y
Y
OE
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
I4
I5
I6
I7
S0
S1
S2
SF00778
TYPE
74F251A
TYPICAL
PROPAGATION
DELAY
4.5ns
TYPICAL
SUPPLY CURRENT
(TOTAL)
19mA
ORDERING INFORMATION
ORDER CODE
DESCRIPTION
COMMERCIAL RANGE
V
CC
= 5V
±10%,
T
amb
= 0°C to +70°C
N74F251AN
N74F251AD
PKG
DWG #
SOT38-4
SOT162-1
16-pin plastic DIP
16-pin plastic SO
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
I0–I7
S0–S2
OE
Y, Y
Data inputs
Select inputs
Output Enable input (active Low)
Data outputs
DESCRIPTION
74F (U.L.) HIGH/LOW
1.0/1.0
1.0/1.0
1.0/1.0
150/40
LOAD VALUE HIGH/LOW
20µA/0.6mA
20µA/0.6mA
20µA/0.6mA
3mA/24mA
NOTE:
One (1.0) FAST unit load is defined as: 20µA in the High state and 0.6mA in the Low state.
LOGIC SYMBOL
4
3
2
1
15
14
13
12
IEC/IEEE SYMBOL
7
11
10
I0
I1
I2
I3
I4
I5
I6
I7
9
4
3
2
1
6
0
G
2
0
7
5
MUX
EN
11
10
9
7
S0
S1
S2
OE
Y
Y
15
14
13
V
CC
= Pin 16
GND = Pin 8
5
6
12
SF00779
SF00780
1996 Jan 05
1
853–0358 16191
Philips Semiconductors
Product specification
8-input multiplexer (3-State)
74F251A
LOGIC DIAGRAM
I0
4
S0
11
I1
3
I2
2
I3
1
I4
15
I5
14
I6
13
I7
12
S1
10
S2
9
7
OE
5
V
CC
= Pin 16
GND = Pin 8
Y
Y
6
SF00781
FUNCTION TABLE
INPUTS
S2
X
L
L
L
L
H
H
H
H
S1
X
L
L
H
H
L
L
H
H
S0
X
L
H
L
H
L
H
L
H
OE
H
L
L
L
L
L
L
L
L
OUTPUTS
Y
Z
I0
I1
I2
I3
I4
I5
I6
I7
Y
Z
I0
I1
I2
I3
I4
I5
I6
I7
NOTES:
H = High voltage level
L = Low voltage level
X = Don’t care
Z = High impedance “off” state
1996 Jan 05
2
Philips Semiconductors
Product specification
8-input multiplexer (3-State)
74F251A
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
V
CC
V
IN
I
IN
V
OUT
I
OUT
T
amb
T
stg
Supply voltage
Input voltage
Input current
Voltage applied to output in High output state
Current applied to output in Low output state
Operating free-air temperature range
Storage temperature
PARAMETER
RATING
–0.5 to +7.0
–0.5 to +7.0
–30 to +5
–0.5 to V
CC
48
0 to +70
–65 to +150
UNIT
V
V
mA
V
mA
°C
°C
RECOMMENDED OPERATING CONDITIONS
SYMBOL
V
CC
V
IH
V
IL
I
IK
I
OH
I
OL
T
amb
Supply voltage
High-level input voltage
Low-level input voltage
Input clamp current
High-level output current
Low-level output current
Operating free-air temperature range
0
PARAMETER
LIMITS
MIN
4.5
2.0
0.8
–18
–3
24
70
NOM
5.0
MAX
5.5
UNIT
V
V
V
mA
mA
mA
°C
DC ELECTRICAL CHARACTERISTICS
(Over recommended operating free-air temperature range unless otherwise noted.)
SYMBOL
PARAMETER
TEST CONDITIONS
1
V
CC
= MIN, V
IL
= MAX,
V
IH
= MIN, I
OH
= MAX
V
CC
= MIN, V
IL
= MAX,
V
IH
= MIN, I
OL
= MAX
V
CC
= MIN, I
I
= I
IK
V
CC
= MAX, V
I
= 7.0V
V
CC
= MAX, V
I
= 2.7V
V
CC
= MAX, V
I
= 0.5V
V
CC
= MAX, V
I
= 2.7V
V
CC
= MAX, V
I
= 0.5V
V
CC
= MAX
V
CC
= MAX
–60
20
17
21
LIMITS
MIN
TYP
2
MAX
UNIT
V
3.3
0.35
0.35
–0.73
0.50
0.50
–1.2
100
20
–0.6
50
–50
–150
27
24
29
V
V
V
V
µA
µA
mA
µA
mA
mA
mA
mA
mA
V
OH
High-level output voltage
±
10%V
CC
±
5%V
CC
±
10%V
CC
±
5%V
CC
2.4
2.7
V
OL
V
IK
I
I
I
IH
I
IL
I
OZH
I
OZL
I
OS
I
CC
Low-level output voltage
Input clamp voltage
Input current at maximum input
voltage
High-level input current
Low-level input current
Off-state output current
High-level voltage applied
Off-state output current
Low-level voltage applied
Short-circuit output current
3
I
CCH
Supply
(total)
S pply current (
l)
)
I
CCL
I
CCZ
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. Not more than one output should be shorted at a time. For testing I
OS
, the use of high-speed test apparatus and/or sample-and-hold
techniques are preferable in order to minimize internal heating and more accurately reflect operational values. Otherwise, prolonged shorting
of a High output may raise the chip temperature well above normal and thereby cause invalid readings in other parameter tests. In any
sequence of parameter tests, I
OS
tests should be performed last.
1996 Jan 05
3
Philips Semiconductors
Product specification
8-input multiplexer (3-State)
74F251A
AC ELECTRICAL CHARACTERISTICS
LIMITS
TEST
CONDITION
MIN
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PZH
t
PZL
t
PHZ
t
PLZ
t
PZH
t
PZL
t
PHZ
t
PLZ
Propagation delay
In to Y
Propagation delay
In to Y
Propagation delay
Sn to Y
Propagation delay
Sn to Y
Output Enable time OE
to Y
Output Disable time
OE to Y
Output Enable time
OE to Y
Output Disable time
OE to Y
Waveform 2
Waveform 1
Waveform 1
Waveform 2
Waveform 1
Waveform 2
Waveform 3
Waveform 4
Waveform 3
Waveform 4
Waveform 3
Waveform 4
Waveform 3
Waveform 4
3.0
3.0
2.5
1.0
4.5
4.0
3.5
2.5
3.5
3.5
2.5
1.0
2.5
2.5
3.5
1.0
V
CC
= +5V
T
amb
= +25°C
C
L
= 50pF
R
L
= 500Ω
TYP
5.0
5.0
4.5
2.5
6.5
5.5
6.0
4.5
5.5
5.0
4.0
4.0
4.0
4.0
5.0
2.0
MAX
7.0
7.0
7.0
5.0
10.0
9.0
9.0
7.0
7.5
7.5
6.5
6.0
6.5
6.5
7.5
4.5
V
CC
= +5V
±
10%
T
amb
= 0°C to +70°C
C
L
= 50pF
R
L
= 500Ω
MIN
2.5
3.0
2.0
1.0
4.0
3.5
3.5
2.5
3.0
3.0
2.0
1.0
2.0
2.5
3.0
1.0
MAX
8.0
8.0
7.5
5.0
11.5
9.5
9.5
7.5
8.5
8.0
7.0
6.5
7.0
7.0
8.0
4.5
ns
ns
ns
ns
ns
ns
ns
ns
SYMBOL
PARAMETER
UNIT
AC WAVEFORMS
For all waveforms, V
M
= 1.5V
V
IN
V
IN
V
M
t
PHL
V
M
t
PLH
V
M
t
PLH
V
M
t
PHL
V
OUT
V
M
V
M
V
OUT
V
M
V
M
SF00782
SF00092
Waveform 1. For Inverting Outputs
Waveform 2. For Non-Inverting Outputs
OE
V
M
t
PZH
V
M
t
PHZ
V
OH
–0.3V
OE
V
M
t
PZL
V
M
t
PLZ
V
M
V
OL
+0.3V
Y, Y
V
M
0V
Y, Y
SF00784
SF00785
Waveform 3. 3-State Output Enable Time to High Level and
Output Disable Time from High Level
Waveform 4. 3-State Output Enable Time to Low Level and
Output Disable Time from Low Level
1996 Jan 05
4
Philips Semiconductors
Product specification
8-input multiplexer (3-State)
74F251A
TEST CIRCUIT AND WAVEFORMS
V
CC
7.0V
V
IN
PULSE
GENERATOR
R
T
D.U.T.
V
OUT
R
L
NEGATIVE
PULSE
90%
V
M
10%
t
THL (
t
f
)
C
L
R
L
t
TLH (
t
r
)
90%
POSITIVE
PULSE
10%
t
THL (
t
f
)
AMP (V)
90%
V
M
t
w
10%
0V
t
w
V
M
10%
t
TLH (
t
r
)
0V
AMP (V)
90%
Test Circuit for 3-State Outputs
SWITCH POSITION
TEST
t
PLZ
t
PZL
All other
SWITCH
closed
closed
open
V
M
Input Pulse Definition
DEFINITIONS:
R
L
= Load resistor;
see AC electrical characteristics for value.
C
L
= 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.
INPUT PULSE REQUIREMENTS
family
amplitude V
M
74F
3.0V
1.5V
rep. rate
1MHz
t
w
500ns
t
TLH
2.5ns
t
THL
2.5ns
SF00777
1996 Jan 05
5
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