MM74C85 Magnitude Comparator Datasheet 

Part Number  MM74C85 
Description  4Bit Magnitude Comparator 
Manufacture  Fairchild 
Total Page  5 Pages 
Datasheet 
October 1987
Revised January 1999
MM74C85
4Bit Magnitude Comparator
General Description
The MM74C85 is a fourbit magnitude comparator which
will perform comparison of straight binary or BCD codes.
The circuit consists of eight comparing inputs (A0, A1, A2,
A3, B0, B1, B2, B3), three cascading inputs (A > B, A < B
and A = B), and three outputs (A > B, A < B and A = B).
This device compares two fourbit words (A and B) and
determines whether they are “greater than,” “less than,” or
“equal to” each other by a high level on the appropriate out
put. For words greater than fourbits, units can be cas
caded by connecting the outputs (A > B, A < B, and A = B)
of the least significant stage to the cascade inputs (A > B, A
< B and A = B) of the nextsignificant stage. In addition the
least significant stage must have a high level voltage
(VIN(1)) applied to the A = B input and low level voltage
(VIN(0)) applied to A > B and A < B inputs.
Features
s Wide supply voltage range: 3.0V to 15V
s Guaranteed noise margin: 1.0V
s High noise immunity: 0.4 VCC (typ.)
s Low power: TTL compatibility:
fan out of 2 driving 74L
s Expandable to 'N' stages
s Applicable to binary or BCD
s Low power pinout: 74L85
Ordering Code:
Order Number Package Number
Package Description
MM74C85N
N16E
16Lead Plastic DualInLine Package (PDIP), JEDEC MS001, 0.300” Wide
Connection Diagram
Pin Assignments for DIP
Top View
© 1999 Fairchild Semiconductor Corporation DS005886.prf
www.fairchildsemi.com

Truth Table
Comparing Inputs
A3, B3 A2, B2 A1, B1
A3 > B3
X
X
A3 < B3
X
X
A3 = B3
A2 > B2
X
A3 = B3
A2 < B2
X
A3 = B3
A2 = B2 A1 > B1
A3 = B3
A2 = B2 A1 < B1
A3 = B3
A2 = B2 A1 = B1
A3 = B3
A2 = B2 A1 = B1
A3 = B3
A2 = B2 A1 = B1
A3 = B3
A2 = B2 A1 = B1
A3 = B3
A2 = B2 A1 = B1
A3 = B3
A2 = B2 A1 = B1
A3 = B3
A2 = B2 A1 = B1
A3 = B3
A2 = B2 A1 = B1
A3 = B3
A2 = B2 A1 = B1
A3 = B3
A2 = B2 A1 = B1
H = HIGH Level, L = LOW Level, X = Irrelevant
Logic Diagram
A0, B0
X
X
X
X
X
X
A0 > B0
A0 < B0
A0 = B0
A0 = B0
A0 = B0
A0 = B0
A0 = B0
A0 = B0
A0 = B0
A0 = B0
Cascading Inputs
A>B A<B A=B
XXX
XXX
XXX
XXX
XXX
XXX
XXX
XXX
HLL
LHL
L LH
L HH
HLH
HHH
HHL
LLL
A>B
H
L
H
L
H
L
H
L
H
L
L
L
H
H
H
L
Outputs
A<B
L
H
L
H
L
H
L
H
L
H
L
H
L
H
H
L
A=B
L
L
L
L
L
L
L
L
L
L
H
H
H
H
L
L
www.fairchildsemi.com
2

Features  MM74C85 4Bit Magnitude Comparator Octo ber 1987 Revised January 1999 MM74C85 4Bit Magnitude Comparator General Desc ription The MM74C85 is a fourbit magni tude comparator which will perform comp arison of straight binary or BCD codes. The circuit consists of eight comparin g inputs (A0, A1, A2, A3, B0, B1, B2, B 3), three cascading inputs (A > B, A < B and A = B), and three outputs (A > B, A < B and A = B). This device compares two fourbit words (A and B) and deter mines whether they are “greater than, ” “less than,” or “equal to” each other by a high level on the appro priate output. For words greater than f ourbits, units can be cascaded by conn ecting the outputs (A > B, A < B, and A = B) of the least significant stage to the cascade inputs (A > B, A < B and A = B) of the nextsignificant stage. In addition the least significant stage m ust have a high level voltage (VIN(1)) applied to the A = B input and low leve l voltage (VIN(0)) applied to A > B and A < B inputs. Features s Wide supp. 
Keywords  MM74C85, datasheet, pdf, Fairchild, 4Bit, Magnitude, Comparator, M74C85, 74C85, 4C85, MM74C8, MM74C, MM74, Equivalent, stock, pinout, distributor, price, schematic, inventory, databook, Electronic, Components, Parameters, parts, cross reference, chip, Semiconductor, circuit, Electric, manual, substitute 

@ 2014 :: Datasheetspdf.com :: Semiconductors datasheet search & download site (Privacy Policy & Contact) 