74F251A 데이터 시트보기 (PDF) - Philips Electronics
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74F251A Datasheet PDF : 5 Pages
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Philips Semiconductors
8-input multiplexer (3-State)
Product specification
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 1
I2 2
I1 3
I0 4
Y5
Y6
OE 7
GND 8
16 VCC
15 I4
14 I5
13 I6
12 I7
11 S0
10 S1
9 S2
SF00778
TYPE
74F251A
TYPICAL
PROPAGATION
DELAY
4.5ns
TYPICAL
SUPPLY CURRENT
(TOTAL)
19mA
ORDERING INFORMATION
ORDER CODE
DESCRIPTION
16-pin plastic DIP
COMMERCIAL RANGE
VCC = 5V ±10%,
Tamb = 0°C to +70°C
N74F251AN
16-pin plastic SO
N74F251AD
PKG
DWG #
SOT38-4
SOT162-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
DESCRIPTION
74F (U.L.) HIGH/LOW
I0–I7
Data inputs
1.0/1.0
S0–S2
Select inputs
1.0/1.0
OE
Output Enable input (active Low)
1.0/1.0
Y, Y
Data outputs
150/40
NOTE:
One (1.0) FAST unit load is defined as: 20µA in the High state and 0.6mA in the Low state.
LOAD VALUE HIGH/LOW
20µA/0.6mA
20µA/0.6mA
20µA/0.6mA
3mA/24mA
LOGIC SYMBOL
IEC/IEEE SYMBOL
4 3 2 1 15 14 13 12
I0 I1 I2 I3 I4 I5 I6 I7
11
S0
10
S1
9
S2
7
OE
YY
VCC = Pin 16
GND = Pin 8
56
SF00779
7
MUX
EN
11
0
10
9
G
0
7
2
4
3
2
1
15
14
13
12
5
6
SF00780
1996 Jan 05
1
853–0358 16191
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