© 2000 Fairchild Semiconductor Corporation

DS006379

www.fairchildsemi.com

August 1986

Revised March 2000

DM74LS85

4-Bit Magnitude Comparator

General Description

These 4-bit magnitude comparators perform comparison of

straight binary or BCD codes. Three fully-decoded deci-

sions about two, 4-bit words (A, B) are made and are exter-

nally available at three outputs. These devices are fully

expandable to any number of bits without external gates.

Words of greater length may be compared by connecting

comparators in cascade. The A

> B, A < B, and A = B out-

puts of a stage handling less-significant bits are connected

to the corresponding inputs of the next stage handling

more-significant bits. The stage handling the least-

significant bits must have a high-level voltage applied to

the A

= B input. The cascading path is implemented with

only a two-gate-level delay to reduce overall comparison

times for long words.

Features

s Typical power dissipation 52 mW

s Typical delay (4-bit words) 24 ns

Ordering Code:

Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.

Connection Diagram

Order Number

Package Number

Package Description

DM74LS85M

M16A

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow

DM74LS85N

N16E

16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide