MC5474F181 Datasheet, PDF (3/5 Pages) Motorola, Inc – 4-BIT ARITHMETIC LOGIC UNIT

MC54/74F181
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol
Parameter
Min Typ
Max
Unit
Test Conditions
VIH
VIL
VIK
IOH
VOH
VOL
IIH
Input HIGH Voltage
2.0
Input LOW Voltage
0.8
Input Clamp Diode Voltage
–1.2
Output Current — HIGH
250
Output HIGH Voltage
54, 74 2.5 3.4
74
2.7 3.4
Output LOW Voltage
0.35
0.5
20
Input HIGH Current
100
M Input
– 0.6
V
Guaranteed Input HIGH Voltage
V
Guaranteed Input LOW Voltage
V
IIN = –18 mA
µA
VOH = 5.5 V
V
IOH = –1.0 mA
V
IOH = –1.0 mA
V
IOL = 20 mA
µA
VIN = 2.7 V
µA
VIN = 7.0 V
mA
VCC = MIN
VCC = MIN, A = B
VCC = 4.5 V
VCC = 4.75 V
VCC = MIN
VCC = MAX
A and B Inputs
IIL
Input LOW Current
S0 _{– 3} Inputs
Cn Input
IOS
Output Short Circuit
Current (Note 2)
– 60
–1.8
– 2.4
– 3.0
–150
mA
VIN = 0.5 V
mA
mA
mA VOUT = 0 V
VCC = MAX
VCC = MAX
ICC
Power Supply Current
43
65
mA
NOTES:
1. For conditions such as MIN or MAX, use the appropriate value specified under guaranteed operating ranges.
2. Not more than one output should be shorted at a time, nor for more than 1 second.
VCC = MAX
FUNCTIONAL DESCRIPTION
The F181 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 pos-
sible logic operations or 16 different arithmetic operations on
active-HIGH or active-LOW operands. The Function Table
lists these operations.
When the Mode Control input (M) is HIGH, all internal carries
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 performs arithmetic op-
erations on the two 4-bit words. The device incorporates full in-
ternal carry lookahead and provides for either ripple carry be-
tween devices using the Cn _{+ 4} output, or for carry lookahead
between packages using the signals P (Carry Propagate) and
G (Carry Generate). In the Add mode, P indicates that F is 15
or more, while G indicates that F is 16 or more. In the Subtract
mode, P indicates that F is zero or less, while G indicates that
F is less than zero. P and G are not affected by carry in. When
speed requirements are not stringent, it can be used in a sim-
ple Ripple Carry mode by connecting the Carry output (Cn _{+ 4)}
signal to the Carry input (Cn) of the next unit. For high-speed
operation the device is used in conjunction with a carry looka-
head circuit. One carry lookahead package is required for
each group of four F181 devices. Carry lookahead can be pro-
vided at various levels and offers high-speed capability over
extremely long word lengths.
The A = B output from the device goes HIGH when all four
F outputs are HIGH and can be used to indicate logic equiva-
lence over four bits when the unit is in the Subtract mode. The
A = B output is open collector and can be wired-AND with other
A = B outputs to give a comparison for more than four bits. The
A = B signal can be used with the Cn _{+ 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 sub-
traction is actually performed by complementary addition (1s
complement), a carry out means borrow; thus a carry is gener-
ated when there is no underflow and no carry is generated
when there is underflow. As indicated, this device 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 operands labeled inside the logic symbol.
FAST AND LS TTL DATA
4-94