DM74LS85N

DM74LS85N Datasheet

DM74LS85 4-Bit Magnitude Comparator

Part	Datasheet
DM74LS85N	DM74LS85N (pdf)

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DM74LS85 4-Bit Magnitude Comparator DM74LS85 4-Bit Magnitude Comparator These 4-bit magnitude comparators perform comparison of straight binary or BCD codes. Three fully-decoded decisions about two, 4-bit words A, B are made and are externally 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 outputs 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 leastsignificant 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. s Typical power dissipation 52 mW s Typical delay 4-bit words 24 ns Ordering Code: Order Number Package Number Package Description DM74LS85M M16A 16-Lead Small Outline Integrated Circuit SOIC , JEDEC MS-012, Narrow DM74LS85N N16E 16-Lead Plastic Dual-In-Line Package PDIP , JEDEC MS-001, Wide Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code. Connection Diagram 2000 Fairchild Semiconductor Corporation DS006379 DM74LS85 Function Table Comparing Inputs A3, B3 A2, B2 A1, B1 A3 > B3 A3 < B3 A3 = B3 A2 > B2 A3 = B3 A2 < B2 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 = Don’t Care A0, B0 X A0 > B0 A0 < B0 A0 = B0 A0 = B0 A0 = B0 A0 = B0 A0 = B0 A0 = B0 Cascading Inputs A>B A<B A=B Outputs A>B H L H L H L H L H L H A<B L H L H L H L H L H L H A=B L H L Logic Diagram DM74LS85 Absolute Maximum Ratings Note 1 Supply Voltage Input Voltage Operating Free Air Temperature Range 0°C to +70°C Storage Temperature Range −65°C to +150°C Note 1 The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation.

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DM74LS85 4-Bit Magnitude Comparator

DM74LS85 4-Bit Magnitude Comparator

These 4-bit magnitude comparators perform comparison of straight binary or BCD codes. Three fully-decoded decisions about two, 4-bit words A, B are made and are externally 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 outputs 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 leastsignificant 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.
s Typical power dissipation 52 mW s Typical delay 4-bit words 24 ns
Ordering Code:

Order Number Package Number

Package Description

DM74LS85M

M16A
16-Lead Small Outline Integrated Circuit SOIC , JEDEC MS-012, Narrow

DM74LS85N

N16E
16-Lead Plastic Dual-In-Line Package PDIP , JEDEC MS-001, Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.

Connection Diagram
2000 Fairchild Semiconductor Corporation DS006379

DM74LS85

Function Table

Comparing

Inputs

A3, B3 A2, B2 A1, B1

A3 > B3

A3 < B3

A3 = B3 A2 > B2

A3 = B3 A2 < B2

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 = Don’t Care

A0, B0 X

A0 > B0 A0 < B0 A0 = B0 A0 = B0 A0 = B0 A0 = B0 A0 = B0 A0 = B0

Cascading

Inputs

A>B A<B A=B

Outputs

A>B H L H L H L H L H L H

A<B L H L H L H L H L H L H

A=B L H L

Logic Diagram

DM74LS85

Absolute Maximum Ratings Note 1

Supply Voltage

Input Voltage

Operating Free Air Temperature Range 0°C to +70°C

Storage Temperature Range
−65°C to +150°C

Note 1 The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation.

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Datasheet ID: DM74LS85N 513814