
Philips Semiconductors
Product specification
74F283
4-bit binary full adder with fast carry
2
1989 Mar 03
853-0364 95944
FEATURES
High speed 4-bit addition
Cascadable in 4-bit increments
Fast Internal carry look-ahead
DESCRIPTION
The 74F283 adds two 4-bit binary words (An plus Bn) plus the
incoming carry. The binary sum appears on the sum outputs
(
Σ0–Σ3) and the outgoing carry (COUT) according to the equation:
CIN+20(A0+B0)+21(A1+B1)+22(A2+B2)+23(A3+B3)
=
Σ0+2Σ1+4Σ2+8Σ3+16COUT
where (+)=plus
Due to the symmetry of the binary add function, the 74F283 can be
used with either all active-High operands (positive logic) or with all
active-Low operands (negative logic). See Function Table. In case of
all active-Low operands (negative logic) the results
Σ1–Σ4 and COUT
should be interpreted also as active-Low. With active-High inputs,
CIN cannot be left open; it must be held Low when no “carry in” is
intended. Interchanging inputs of equal weight does not affect the
operation, thus A0, B0, CIN can arbitrarily be assigned to pins 5, 6,
7, etc.
Due to pin limitations, the intermediate carries of the 74F283 are not
brought out for use as inputs or outputs. However, other means can
be used to effectively insert a carry into, or bring a carry out from, an
intermediate stage.
PIN CONFIGURATION
7
14
13
12
11
10
9
6
5
4
3
2
1
VCC
B2
A3
B3
COUT
A0
B1
B0
Σ1
GND
A1
Σ0
SF00852
Σ3
Σ2
CIN
A2
8
16
15
TYPE
TYPICAL
PROPAGATION
DELAY
TYPICAL
SUPPLY CURRENT
(TOTAL)
74F283
6.5ns
40mA
ORDERING INFORMATION
DESCRIPTION
COMMERCIAL RANGE
VCC = 5V ±10%,
Tamb = 0°C to +70°C
PKG DWG #
16-pin plastic DIP
N74F283N
SOT38-4
16-pin plastic SO
N74F283D
SOT109-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
DESCRIPTION
74F(U.L.)
HIGH/LOW
LOAD VALUE
HIGH/LOW
A0 - A3
A operand inputs
1.0/2.0
20
A/1.2mA
B0 - B3
B operand inputs
1.0/2.0
20
A/1.2mA
CIN
Carry input
1.0/1.0
20
A/0.6mA
COUT
Carry output
50/33
1.0mA/20mA
Σ0–Σ3
Sum outputs
50/33
1.0mA/20mA
NOTE:
One (1.0) FAST Unit Load is defined as: 20
A in the High state and 0.6mA in the Low state.
LOGIC SYMBOL
5
6
3
2
14 15 12 11
41
Σ1
Σ0
A0 B0 A1 B1 A2 B2 A3 B3
SF00853
13
10
Σ3
Σ2
9
7
CIN
COUT
VCC=Pin 16
GND=Pin 8
LOGIC SYMBOL (IEEE/IEC)
5
3
14
12
6
2
15
11
7
10
9
Σ
SF00854
13
1
4
CO
CI
0
3
0
3
P
Q
0
3