NSC DM74283 4-bit binary full adder (with fast carry) Datasheet

54283/DM74283
4-Bit Binary Full Adder (with Fast Carry)
General Description
The ’283 high speed 4-bit binary full adders with internal
carry lookahead accept two 4-bit binary words (A0–A3, B0 –
B3) and a Carry input (C0). They generate the binary Sum
outputs (S0–S3) and the Carry output (C4) from the most
significant bit. They operate with either active HIGH or active LOW operands (positive or negative logic).
Connection Diagram
Dual-In-Line Package
TL/F/9786 – 1
Order Number 54283DMQB, 54283FMQB or DM74283N
See NS Package Number J16A, N16E or W16A
Pin Names
A0–A3
B0–B3
C0
S0–S3
C4
C1995 National Semiconductor Corporation
TL/F/9786
Description
A Operand Inputs
B Operand Inputs
Carry Input
Sum Outputs
Carry Output
RRD-B30M115/Printed in U. S. A.
54283/DM74283 4-Bit Binary Full Adder (with Fast Carry)
June 1989
Absolute Maximum Ratings (Note)
Note: The ‘‘Absolute Maximum Ratings’’ are those values
beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The
parametric values defined in the ‘‘Electrical Characteristics’’
table are not guaranteed at the absolute maximum ratings.
The ‘‘Recommended Operating Conditions’’ table will define
the conditions for actual device operation.
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Supply Voltage
Input Voltage
Operating Free Air Temperature Range
54
DM74
7V
b 55§ C to a 125§ C
0§ C to a 70§ C
Storage Temperature Range
b 65§ C to a 150§ C
5.5V
Recommended Operating Conditions
Symbol
54283
Parameter
VCC
Supply Voltage
VIH
High Level Input Voltage
VIL
Low Level Input Voltage
IOH
High Level Output Current
IOL
Low Level Output Current
TA
Free Air Operating Temperature
DM74283
Units
Min
Nom
Max
Min
Nom
Max
4.5
5
5.5
4.75
5
5.25
2
2
V
0.8
0.8
V
b 0.4
b 0.4
mA
16
b 55
V
125
0
16
mA
70
§C
Max
Units
b 1.5
V
Electrical Characteristics
Over recommended operating free air temperature range (unless otherwise noted)
Symbol
VI
Parameter
Conditions
Input Clamp Voltage
VCC e Min, II e b12 mA
VOH
High Level Output Voltage
VCC e Min, IOH e Max
VIL e Max
VOL
Low Level Output Voltage
VCC e Min, IOL e Max
VIH e Min
II
Input Current @ Max
Input Voltage
VCC e Max, VI e 5.5V
IIH
High Level Input Current
IIL
IOS
IOS
ICCH
Min
2.4
Typ
(Note 1)
3.4
0.4
V
1
mA
VCC e Max, VI e 2.4V
40
mA
Low Level Input Current
VCC e Max, VI e 0.4V
b 1.6
mA
Short Circuit
Output Current at Sn
VCC e Max
(Note 2)
54
b 20
b 55
DM74
b 20
b 55
Short Circuit
Output Current at C4
VCC e Max
(Note 2)
54
b 20
b 70
DM74
b 18
b 70
Supply Current with
Outputs High
VCC e Max
54
99
DM74
110
Note 1: All typicals are at VCC e 5V, TA e 25§ C.
Note 2: Not more than one output should be shorted at a time.
2
0.2
V
mA
mA
mA
Switching Characteristics
VCC e a 5.0V, TA e a 25§ C (See Section 1 for waveforms and load configurations)
Symbol
CL e 15 pF, RL e 400X
Parameter
Min
Units
Max
tPLH
tPHL
Propagation Delay
C0 or Sn
21
21
ns
tPLH
tPHL
Propagation Delay
An or Bn to Sn
24
24
ns
tPLH
tPHL
Propagation Delay
C0 to C4
14
16
ns
tPLH
tPHL
Propagation Delay
An or Bn to C4
14
16
ns
Functional Description
The ’283 adds two 4-bit binary words (A plus B) plus the
incoming carry C0. The binary sum appears on the Sum
(S0 – S3) and outgoing carry (C4 outputs. The binary weight
of the various inputs and outputs is indicated by the subscript numbers, representing powers of two.
20 (A0 a B0 a C0) a 21 (A1 a B1) a 22 (A2 a B2) a
23 (A3 a B3) e S0 a 2S1 a 4S2 a 8S3 a 16C4
Where ( a ) e plus
Interchanging inputs of equal weight does not affect the operation. Thus C0, A0, B0 can be arbitrarily assigned to pins
5, 6 and 7. Due to the symmetry of the binary add function,
the ’283 can be used either with all inputs and outputs active HIGH (positive logic) or with all inputs and outputs active LOW (negative logic). Note that if C0 is not used it must
be tied LOW for active HIGH logic or tied HIGH for active
LOW logic.
Example:
Due to pin limitations, the intermediate carries of the ’283
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. Figure a
shows a way of making a 3-bit adder. Tying the operand
inputs of the fourth adder (A3, B3) LOW makes S3 dependent ony on, and equal to, the carry from the third adder.
Using somewhat the same principle,Figure b shows a way
of dividing the ’283 into a 2-bit and a 1-bit adder. The third
stage adder (A2, B2, S2) is used merely as a means of
getting a carry (C10) signal into the fourth stage (via A2 and
B2) and bringing out the carry from the second stage on S2.
Note that as long as A2 and B2 are the same, whether
HIGH or LOW, they do not infuence S2. Similarly, when A2
and B2 are the same the carry into the third stage does not
influence they carry out of the third stage. Figure c shows a
method of implementing a 5-input encoder, where the inputs
are equally weighted. The outputs S0, S1 and S2 present a
binary number equal to the number of inputs I1 – I5 that are
true. Figure d shows one method of implementing a 5-input
majority gate. When three or more of the inputs I1 – I5 are
true, the output M5 is true.
C0 A0 A1 A2 A3 B0 B1 B2 B3 S0 S1 S2 S3 C4
Logic Levels L L H L H H L L H H H L L H
Active HIGH 0 0 1 0 1 1 0 0 1 1 1 0 0 1
Active LOW 1 1 0 1 0 0 1 1 0 0 0 1 1 0
Active HIGH: 0 a 10 a 9 e 3 a 16
Active LOW: 1 a 5 a 6 e 12 a 0
TL/F/9786 – 3
FIGURE a. 3-Bit Adder
TL/F/9786 – 4
FIGURE b. 2-Bit and 1-Bit Adders
3
Functional Description (Continued)
TL/F/9786 – 5
FIGURE c. 5-Input Encoder
TL/F/9786 – 6
FIGURE d. 5-Input Majority Gate
Logic Symbol
TL/F/9786 – 2
VCC e Pin 16
GND e Pin 8
Logic Diagram
TL/F/9786 – 7
4
Physical Dimensions inches (millimeters)
16-Lead Ceramic Dual-In-Line Package (J)
Order Number 54283DMQB
NS Package Number J16A
16-Lead Molded Dual-In-Line Package (N)
Order Number DM74283N
NS Package Number N16E
5
54283/DM74283 4-Bit Binary Full Adder (with Fast Carry)
Physical Dimensions inches (millimeters) (Continued)
16-Lead Ceramic Flat Package (W)
Order Number 54283FMQB
NS Package Number W16A
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