DM93S41 4-Bit Arithmetic Logic Unit
October 1988
Revised May 2000
DM93S41
4-Bit Arithmetic Logic Unit
General Description
The DM93S41 4-bit arithmetic logic units can perform all
the possible 16 logic operations on two variables and a
variety of arithmetic operations; the Add and Subtract
modes are the most important.
Ordering Code:
Order Number
DM93S41N
Package Number
N24A
Package Description
24-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-010, 0.600 Wide
Logic Symbols
Active LOW Operands
Connection Diagram
Active HIGH Operands
Pin Descriptions
Pin Name
A0–A3, B0–B3
S0–S3
M
Cn
F0–F3
A
=
B
G
P
C
n+4
Description
Operand Inputs (Active LOW)
Function Select Inputs
Mode Control Input
Carry Input
Function Outputs (Active LOW)
Comparator Output
Carry Generate Output (Active LOW)
Carry Propagate Output (Active LOW)
Carry Output
© 2000 Fairchild Semiconductor Corporation
DS009805
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DM93S41
Functional Description
The DM93S41 is a 4-bit high speed parallel arithmetic logic
unit (ALU). Controlled by the four Function Select inputs
(S0–S3) and the Mode Control input (M), it can perform all
the 16 possible operations or 16 different arithmetic opera-
tions on active HIGH or active LOW operands. The Func-
tion Table below lists these operations.
When the Mode Control input (M) is HIGH, all internal car-
ries are inhibited and the device performs logic operations
on the individual bits as listed. When the Mode Control
input is LOW, the carries are enabled and the device per-
forms arithmetic operations on the two 4-bit words. The
device incorporates full internal carry lookahead and pro-
vides for either ripple carry between devices using the C
n+4
output, or for carry lookahead between packages using the
signals P (Carry Propagate) and G (Carry Generate). P
and G are not affected by carry in. When speed require-
ments are not stringent, the DM93S41 can be used in a
simple ripple carry mode by connecting the Carry output
(C
n+4
) signal to the Carry input (C
n
) of the next unit. For
super high speed operation the Schottky DM93S41 should
be used in conjunction with the '42 carry lookahead circuit.
The A
=
B output from the DM93S41 goes HIGH when all
four F
n
outputs are HIGH and can be used to indicate logic
equivalence over four bits when the unit is in the subtract
mode. The A
=
B output is open-collector and can be wired-
AND with the other A
=
B outputs to give a comparison for
more than four bits. The A
=
B signal can also be used with
the C
n+4
signal to indicate A
>
B and A
<
B.
The Function Table lists the arithmetic operations that are
performed without a carry in. An incoming carry adds a one
to each operation. Thus select code LHHL generates A
minus B minus 1 (2s complement notation) without a carry
in and generates A minus B when a carry is applied.
Because subtraction is actually performed by complemen-
tary addition (1s complement), a carry out means borrow;
thus a carry is generated when there is no underflow and
no carry is generated when there is underflow.
As indicated the '41 can be used with either active LOW
inputs producing active LOW outputs or with active HIGH
inputs producing active HIGH outputs. For either case the
table lists the operations that are performed to the oper-
ands labeled inside the logic symbol.
Function Table
Mode Select
Inputs
S3
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
S2
L
L
L
L
H
H
H
H
L
L
L
L
H
H
H
H
S1
L
L
H
H
L
L
H
H
L
L
H
H
L
L
H
H
S0
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
A
AB
A
+
B
Logic 1
A
+
B
B
A
⊕
B
A
+
B
AB
A
⊕
B
B
A
+
B
Logic 0
AB
AB
A
(M
=
H)
Active LOW Inputs
& Outputs
Logic Arithmetic (Note 2)
(M
=
L) (C
n
=
L)
A minus 1
AB minus 1
AB minus 1
minus 1
A plus (A
+
B)
AB plus (A
+
B)
A minus B minus 1
A
+
B
A plus (A
+
B)
A plus B
AB plus (A
+
B)
A
+
B
A plus A (Note 1)
AB plus A
AB minus A
A
A
A
+
B
AB
Logic 0
AB
B
A
⊕
B
AB
A
+
B
A
⊕
B
B
AB
Logic 1
A
+
B
A
+
B
A
(M
=
H)
A
A
+
B
A
+
B
minus 1
A plus AB
(A
+B)
plus AB
A minus B minus 1
AB minus 1
A plus AB
A plus B
(A
+
B) plus AB
AB minus 1
A plus A (Note 1)
(A
+
B) plus A
(A
+
B) plus A
A minus 1
Active HIGH Inputs
& Outputs
Logic Arithmetic (Note 2)
(M
=
L) (C
n
=
H)
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
Note 1:
Each bit is shifted to the next more significant position
Note 2:
Arithmetic operations expressed in 2s complement notation
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DM93S41
Absolute Maximum Ratings
(Note 3)
Supply Voltage
Input Voltage:
Operating Free Air Temperature Range
Storage Temperature Range
7V
5.5V
0°C to
+70°C
−65°C
to
+150°C
Note 3:
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 tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Symbol
V
CC
V
IH
V
IL
I
OH
I
OL
T
A
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Free Air Operating Temperature
0
Parameter
Min
4.75
2
0.8
−1
20
70
Nom
5
Max
5.25
Units
V
V
V
mA
mA
°C
Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
V
I
V
OH
V
OL
I
I
I
IH
I
IL
I
OS
I
CCL
Parameter
Input Clamp Voltage
HIGH Level
Output Voltage
LOW Level
Output Voltage
Input Current @ Max Input Voltage
HIGH Level Input Current
LOW Level Input Current
Short Circuit Output Current
Supply Current
Conditions
V
CC
=
Min, I
I
= −
18 mA
V
CC
=
Min, I
OH
=
Max
V
IL
=
Max
V
CC
=
Min, I
OL
=
Max
V
IH
=
Min
V
CC
=
Max, V
I
=
5.5V
V
CC
=
Max, V
I
=
2.7V
V
CC
=
Max, V
I
=
0.5V
V
CC
=
Max (Note 5)
V
CC
=
Max
M, S0–S3
=
4.5V
All Other Inputs
=
0V
I
CCH
Supply Current
V
CC
=
Max
C
n
, B0–B3
=
GND
All Other Inputs
=
4.5V
Note 4:
All typicals are at V
CC
=
5V, T
A
=
25°C.
Note 5:
Not more than one output should be shorted at a time, and the duration should not exceed one second.
Min
Typ
(Note 4)
Max
−1.2
Units
V
V
2.7
3.4
0.35
0.5
1
50
−1.6
V
mA
µA
mA
mA
mA
−40
−100
150
140
mA
5
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