54LS85DMQB - National Semiconductor

TL/F/6379

54LS85/DM54LS85/DM74LS85 4-Bit Magnitude Comparators

June 1989

54LS85/DM54LS85/DM74LS85

4-Bit Magnitude Comparators

General Description

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 expand-

able to any number of bits without external gates. Words of

greater length may be compared by connecting compara-

tors in cascade. The A lB, A kB, and A eB outputs of a

stage handling less-significant bits are connected to the cor-

responding inputs of the next stage handling more-signifi-

cant bits. The stage handling the least-significant bits must

have a high-level voltage applied to the A eB input. The

cascading path is implemented with only a two-gate-level

delay to reduce overall comparison times for long words.

Features

YTypical power dissipation 52 mW

YTypical delay (4-bit words) 24 ns

YAlternate Military/Aerospace device (54LS85) is avail-

able. Contact a National Semiconductor Sales Office/

Distributor for specifications.

Connection Diagram

Dual-In-Line Package

TL/F/6379–1

Order Number 54LS85DMQB,

54LS85FMQB, 54LS85LMQB,

DM54LS85J, DM54LS85W,

DM74LS85M or DM74LS85N

See NS Package Number E20A,

J16A, M16A, N16E or W16A

Function Table

Comparing Cascading Outputs

Inputs Inputs

A3, B3 A2, B2 A1, B1 A0, B0 A lBA

A3 lB3 X X X X X X H L L

A3 kB3 X X X X X X L H L

A3 eB3 A2 lB2 X X X X X H L L

A3 eB3 A2 kB2 X X X X X L H L

A3 eB3 A2 eB2 A1 lB1 X X X X H L L

A3 eB3 A2 eB2 A1 kB1 X X X X L H L

A3 eB3 A2 eB2 A1 eB1 A0 lB0 X X X H L L

A3 eB3 A2 eB2 A1 eB1 A0 kB0 X X X L H L

A3 eB3 A2 eB2 A1 eB1 A0 eB0 H L L H L L

A3 eB3 A2 eB2 A1 eB1 A0 eB0 L H L L H L

A3 eB3 A2 eB2 A1 eB1 A0 eB0LLHLLH

A3 eB3 A2 eB2 A1 eB1 A0 eB0XXHLLH

A3 eB3 A2 eB2 A1 eB1 A0 eB0HHLLLL

A3 eB3 A2 eB2 A1 eB1 A0 eB0LLLHHL

High Level, L eLow Level, X eDon’t Care

C1995 National Semiconductor Corporation RRD-B30M105/Printed in U. S. A.

Absolute Maximum Ratings (Note)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales

Office/Distributors for availability and specifications.

Supply Voltage 7V

Input Voltage 7V

Operating Free Air Temperature Range

DM54LS and 54LS b55§Ctoa

125§C

DM74LS 0§Ctoa

70§C

Storage Temperature Range b65§Ctoa

150§C

Note:

The ‘‘Absolute Maximum Ratings’’ are those values

beyond which the safety of the device cannot be guaran-

teed. The device should not be operated at these limits. The

parametric values defined in the ‘‘Electrical Characteristics’’

table are not guaranteed at the absolute maximum ratings.

The ‘‘Recommended Operating Conditions’’ table will define

the conditions for actual device operation.

Recommended Operating Conditions

Symbol Parameter DM54LS85 DM74LS85 Units

Min Nom Max Min Nom Max

VCC Supply Voltage 4.5 5 5.5 4.75 5 5.25 V

VIH High Level Input Voltage 2 2 V

VIL Low Level Input Voltage 0.7 0.8 V

IOH High Level Output Current b0.4 b0.4 mA

IOL Low Level Output Current 4 8 mA

TAFree Air Operating Temperature b55 125 0 70 §C

Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)

Symbol Parameter Conditions Min Typ Max Units

(Note 1)

VIInput Clamp Voltage VCC eMin, IIeb

18 mA b1.5 V

VOH High Level Output VCC eMin, IOH eMax DM54 2.5 3.4 V

Voltage VIL eMax, VIH eMin DM74 2.7 3.4

VOL Low Level Output VCC eMin, IOL eMax DM54 0.25 0.4

Voltage VIL eMax, VIH eMin DM74 0.35 0.5 V

IOL e4 mA, VCC eMin DM74 0.25 0.4

IIInput Current @Max VCC eMax A kB 0.1

Input Voltage VIe7V AlB 0.1 mA

Others 0.3

IIH High Level Input VCC eMax A kB20

Current VIe2.7V AlB20mA

Others 60

IIL Low Level Input VCC eMax A kBb0.4

Current VIe0.4V AlBb0.4 mA

Others b1.2

IOS Short Circuit VCC eMax DM54 b20 b100 mA

Output Current (Note 2) DM74 b20 b100

ICC Supply Current VCC eMax (Note 3) 10 20 mA

Note 1: All typicals are at VCC e5V, TAe25§C.

Note 2: Not more than one output should be shorted at a time, and the duration should not exceed one second.

Note 3: ICC is measured with all outputs open, A eB grounded and all other inputs at 4.5V.

Switching Characteristics at VCC e5V and TAe25§C (See Section 1 for Test Waveforms and Output Load)

From To Number of RLe2kX

Symbol Parameter Input Output Gate Levels CLe15 pF CLe50 pF Units

Min Max Min Max

tPLH Propagation Delay Time Any A or B A kB, 33642

Low-to-High Level Output Data Input A lBns

B 4 40 40

tPHL Propagation Delay Time Any A or B A kB, 33040

High-to-Low Level Output Data Input A lBns

B 4 30 40

tPLH Propagation Delay Time A kBAlB 1 22 26 ns

Low-to-High Level Output or A eB

tPHL Propagation Delay Time A kBAlB 1 17 26 ns

High-to-Low Level Output or A eB

tPLH Propagation Delay Time AeBA

B 2 20 25 ns

Low-to-High Level Output

tPHL Propagation Delay Time AeBA

B 2 17 26 ns

High-to-Low Level Output

tPLH Propagation Delay Time A lBAkB 1 22 26 ns

Low-to-High Level Output or A eB

tPHL Propagation Delay Time A lBAkB 1 17 26 ns

High-to-Low Level Output or A eB

Logic Diagram

TL/F/6379–2

Physical Dimensions inches (millimeters)

Chip Carrier Package (E)

Order Number 54LS85LMQB

NS Package Number E20A

16-Lead Ceramic Dual-In-Line Package (J)

Order Number 54LS85DMQB or DM54LS85J

NS Package Number J16A

Physical Dimensions inches (millimeters) (Continued)

16-Lead Small Outline Molded Package (M)

Order Number DM74LS85M

NS Package Number M16A

16-Lead Molded Dual-In-Line Package (N)

Order Number DM74LS85N

NS Package Number N16E

54LS85/DM54LS85/DM74LS85 4-Bit Magnitude Comparators

Physical Dimensions inches (millimeters) (Continued)

16-Lead Ceramic Flat Package (W)

Order Number 54LS85FMQB or DM54LS85W

NS Package Number W16A

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failure to perform, when properly used in accordance support device or system, or to affect its safety or

with instructions for use provided in the labeling, can effectiveness.

be reasonably expected to result in a significant injury

to the user.

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