MM54HC181/MM74HC181
Arithmetic Logic Units/Function Generators
General Description
These arithmetic logic units (ALU)/function generators utilize
advanced silicon-gate CMOS technology. They possess
the high noise immunity and low power consumption of
standard CMOS integrated circuits, as well as the ability to
drive 10 LS-TTL loads.
The MM54HC181/MM74HC181 are arithmetic logic unit
(ALU)/function generators that have a complexity of 75
equivalent gates on a monolithic chip. These circuits perform
16 binary arithmetic operations on two 4-bit words as
shown in Tables 1 and 2. These operations are selected by
the four function-select lines (S0, S1, S2, S3) and include
addition, subtraction, decrement, and straight transfer.
When performing arithmetic manipulations, the internal carries
must be enabled by applying a low-level voltage to the
mode control input (M). A full carry look-ahead scheme is
made available in these devices for fast, simultaneous carry
generation by means of two cascade-outputs (pins 15 and
17) for the four bits in the package. When used in conjunction
with the MM54HC182 or MM74HC182, full carry lookahead
circuits, high-speed arithmetic operations can be performed.
The method of cascading HC182 circuits with these
ALU's to provide multi-level full carry look-ahead is illustrated
under typical applications data for the MM54HC182/
MM74HC182.
If high speed is not of importance, a ripple-carry input (Cn)
and a ripple-carry output (Cna4) are available. However,
the ripple-carry delay has also been minimized so that arithmetic
manipulations for small word lengths can be performed
without external circuitry.
Features
Y Full look-ahead for high-speed operations on
long words
Y Arithmetic operating modes:
Addition
Subtraction
Shift operand a one position magnitude comparison
Plus twelve other arithmetic operations
Y Logic function modes:
Exclusive-OR
Comparator
AND, NAND, OR, NOR
Plus ten other logic operations
Y Wide operating voltage range: 2V±6V
Y Low input current: 1 mA maximum
Y Low quiescent current: 80 mA maximum