MC74AC521 Datasheet, PDF (1/6 Pages) Motorola, Inc – 8-BIT IDENTITY COMPARATOR

8ĆBit Identity Comparator
The MC74AC521/74ACT521 is an expandable 8-bit comparator. It
compares two words of up to eight bits each and provides a LOW output when
the two words match bit for bit. The expansion input IA=B also serves as an
active LOW enable input.
• Compares Two 8-Bit Words in 6.5 ns Typ
• Expandable to Any Word Length
• 20-Pin Package
• Outputs Source/Sink 24 mA
• ′ACT521 has TTL-Compatible Inputs
VCC OA=B B7 A7 B6 A6 B5 A5 B4 A4
20 19 18 17 16 15 14 13 12 11
MC74AC521
MC74ACT521
8-BIT IDENTITY
COMPARATOR
N SUFFIX
CASE 738-03
PLASTIC
1 2 3 4 5 6 7 8 9 10
IA=B A0 B0 A1 B1 A2 B2 A3 B3 GND
DW SUFFIX
CASE 751D-04
PLASTIC
PIN NAMES
A0–A7
B0–B7
IA=B
OA=B
Word A Inputs
Word B Inputs
Expansion or Enable Input
Identity Output
TRUTH TABLE
Inputs
Outputs
IA=B
L
L
H
H
A, B
A = B*
A≠B
A = B*
A≠B
OA=B
L
H
H
H
H = HIGH Voltage Level
L = LOW Voltage Level
*A0=B0, A1=B1, A2=B2, etc.
LOGIC SYMBOL
B7 A7 B6 A6 B5 A5 B4 A4 B3 A3 B2 A2 B1 A1 B0 A0
IA=B
OA=B
FACT DATA
5-1