74LS85 4-bit Magnitude Comparator

The 74LS series of integrated circuits (ICs) was one of the most popular logic families of transistor-transistor logic (TTL) logic chips. 74LS series is a bipolar, low-power Schottky IC. 74LS85 four-bit magnitude comparison of straight binary and straight codes. Three fully decoded decisions words (A, 8) are made and are externally outputs. These devices are fully expa number of bits without external gates

74LS85 Features

• Performs Comparison of Binary or BCD Codes
• Can Compare Greater Than, Less Than and Equal
• Words of Greater Length Can be Compared by Cascading
• Operating Temperature up to 70°C
• Standard TTL Switching Voltages

74LS85 Specifications

Supply Voltage	4.75 – 5.25Vdc
Maximum Clock Frequency	40Mhz
Power Dissipation	2mW/gate @100kHz
Minimum Output Current	8mA
Propagation Delay	10nS
Fan Out (TTL Loads)	20

74LS85 Pinout Diagram

74LS85 Pin Description

Pin No	Pin Name	Description
1	B3	Data Input B3
2	1A<B	Cascading Output Pin if A<B
3	1A=B	Cascading Output Pin if A=B
4	1A>B	Cascading Output Pin if A>B
5	0A>B	Output Pin if A>B
6	0A=B	Output Pin if A=B
7	0A<B	Output Pin if A<B
8	GND	Ground
9	B0	Data Input B0
10	A0	Data Input A0
11	B1	Data Input B1
12	A1	Data Input A1
13	A2	Data Input A2
14	B2	Data Input B2
15	A3	Data Input A3
16	VCC	Positive Supply

74LS85 Circuit

Here is a simple circuit of 1 Bit Comparators using Logic Gates NOT, AND and NOR.

Applications

• Can be used to compare two different readings
• Temperature, position, etc. are compared with a reference value

74LS85 Alternative Equivalent

74LS682, 74LS688

Download the 74LS85 4-bit Magnitude Comparator Datasheet from the link given below.