Philips Semiconductors
Product specification
Buffers/Drivers
74F455 Octal Buffer/Driver with Parity, Inverting (3-State)
74F456 Octal Buffer/Driver with Parity, Non-Inverting (3-State)
FEATURES
74F455,*
74F456
•
High impedance NPN base inputs for reduced loading
(40µA in High and Low states)
DESCRIPTION
The 74F455 and 74F456 are octal buffers and line drivers with parity
generation/checking designed to be employed as memory address
drivers, clock drivers and bus-oriented transmitters/receivers. These
parts include parity generator/checker to improve PC board density.
TYPICAL
PROPAGATION
DELAY
6.5ns
7.5ns
•
74F456 combines 74F244 and 74F280A functions in one package
•
74F456 is a center pin version of the 74F656A
•
74F456 Non-Inverting
•
3-State outputs sink 64mA and source 15mA
•
24-pin plastic Slim DIP (300 mil) package
•
Broadside pinout simplifies PC board layout
TYPE
74F455
74F456
TYPICAL SUPPLY CURRENT
(TOTAL)
64mA
64mA
ORDERING INFORMATION
DESCRIPTION
COMMERCIAL
RANGE
V
CC
= 5V
±10%,
T
amb
= 0°C to +70°C
N74456N
N74456D
PKG DWG #
24-pin plastic Slim
DIP (300mil)
24-pin plastic SOL
SOT222-1
SOT137-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
D0–D7
PI
OE0, OE1
ΣE, ΣO
Q0–Q7
Data inputs
Parity input
Output Enable inputs (active Low)
Parity outputs
Data outputs (75F455)
DESCRIPTION
74F(U.L.)
HIGH/LOW
2.0/0.066
1.0/0.033
1.0/0.033
750/106.7
750/106.7
LOAD VALUE
HIGH/LOW
40µA/40µA
20µA/20µA
20µA/20µA
15mA/64mA
15mA/64mA
15mA/64mA
Q0–Q7
Data outputs (75F456)
750/106.7
NOTE:
One (1.0) FAST Unit Load (U.L.) is defined as 20µA in the High state and 0.6mA in the Low state.
PIN CONFIGURATION – 74F455
OE0
OE1
PI
D0
D1
D2
V
CC
D3
D4
D5
D6
D7
1
2
3
4
5
6
7
8
9
10
11
12
24
ΣO
23
ΣE
22 Q0
21 Q1
20 Q2
19 GND
18 GND
17 Q3
16 Q4
15 Q5
14 Q6
13 Q7
PIN CONFIGURATION – 74F456
OE0
OE1
PI
D0
D1
D2
V
CC
D3
D4
D5
D6
D7
1
2
3
4
5
6
7
8
9
10
11
12
24
ΣO
23
ΣE
22 Q0
21 Q1
20 Q2
19 GND
18 GND
17 Q3
16 Q4
15 Q5
14 Q6
13 Q7
SF00969
SF00958
* Discontinued part. Please see the Discontinued Products List.
1999 Jan 08
2
853–0371 20616
Philips Semiconductors
Product specification
Buffers/Drivers
74F455,* 74F456
LOGIC SYMBOL – 74F455
4
5
6
8
9
10
11
12
LOGIC SYMBOL – 74F456
4
5
6
8
9
10
11
12
D0
3
1
2
PI
OE0
D1
D2
D3
D4
D5
D6
D7
3
23
1
24
2
D0
PI
OE0
D1
D2
D3
D4
D5
D6
D7
ΣE
ΣO
ΣE
ΣO
23
24
OE1
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
OE1
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
22
V
CC
= Pin 7
GND = Pin 18, 19
21
20
17
16
15
14
13
SF00959
22
V
CC
= Pin 7
GND = Pin 18, 19
21
20
17
16
15
14
13
SF00960
LOGIC SYMBOL (IEEE/IEC) – 74F455
3,5,6,7,8
9,10,11,12
3
1
2
4
5
6
8
9
10
11
12
3,5,6,7,8
9,10,11,12
2K
[EVEN]
[ODD]
23
24
LOGIC SYMBOL (IEEE/IEC) – 74F456
3,5,6,7,8
9,10,11,12
3
1
P3
1
EN4
22
21
20
17
16
15
14
13
3,5,6,7,8
9,10,11,12
2K
[EVEN]
[ODD]
23
24
P3
w1
EN4
22
21
20
17
16
15
14
13
2
4
5
6
8
9
10
11
12
Z5
Z6
Z7
Z8
Z9
Z10
Z11
Z12
4
Z5
Z6
Z7
Z8
Z9
Z10
Z11
Z12
4
SF00961
SF00962
FUNCTION TABLE
INPUTS
OUTPUTS
74F455
OE0
L
L
H
X
H
L
Z
X
=
=
=
=
OE1
L
L
X
H
Dn
L
H
X
X
Qn
H
L
Z
Z
74F456
Qn
L
H
Z
Z
FUNCTION TABLE for PARITY OUTPUTS
INPUTS
Number of inputs, High (PI, D0 - D7)
Even - 0, 2, 4, 6, 8
Odd - 1, 3, 5, 7, 9
Any OEn = High
H
L
Z
X
=
=
=
=
High voltage level
Low voltage level
High impedance “off” state
Don’t care
ΣE
H
L
Z
OUTPUTS
ΣO
L
H
Z
High voltage level
Low voltage level
High impedance “off” state
Don’t care
* Discontinued part. Please see the Discontinued Products List.
1999 Jan 08
3
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