74ls243

Revised January 2000

DM74LS243

Quadruple Bus Transceiver

General Description

This four data line transceiver is designed for asynchro-nous two-way communications between data buses. It canbe used to drive terminated lines down to 133Ω.

Features

sTwo-way asynchronous communication between databusessPNP inputs reduce DC loading on bus linesHysteresis at data inputs improves noise margin

Ordering Code:

Order NumberDM74LS243MDM74LS243N

Package Number

M14AN14A

Package Description

14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-120, 0.150 Narrow14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide

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

Connection DiagramFunction Table

ControlInputs

G ABHLHL

I = InputO = Output

H = HIGH Logic LevelL = LOW Logic Level

Note 1: Possibly destructive oscillation may occur if the transceivers areenabled in both directions at once.

Data PortStatus

GBAHHLL

IAO(Note 1)

ISOLATED

OBI(Note 1)

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DM74LS243Absolute Maximum Ratings(Note 2)

Supply VoltageInput VoltageAny GA or B

Operating Free Air Temperature RangeStorage Temperature Range

7V5.5V

0°C to +70°C−65°C to +150°C

7V

Note 2: The “Absolute Maximum Ratings” are those values beyond whichthe safety of the device cannot be guaranteed. The device should not beoperated at these limits. The parametric values defined in the ElectricalCharacteristics tables are not guaranteed at the absolute maximum ratings.The “Recommended Operating Conditions” table will define the conditionsfor actual device operation.

Recommended Operating Conditions

SymbolVCCVIHVILIOHIOLTA

Supply Voltage

HIGH Level Input VoltageLOW Level Input VoltageHIGH Level Output CurrentLOW Level Output CurrentFree Air Operating Temperature

0

Parameter

Min4.752

0.8−152470

Nom5

Max5.25

UnitsVVVmAmA°C

Electrical Characteristics

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

Parameter

Input Clamp VoltageHysteresis (VT+ − VT−)(Data Inputs Only)HIGH Level Output Voltage

VCC = Min, VIH = MinVIL = Max, IOH = −1 mAVCC = Min, VIH = MinVIL = Max, IOH = −3 mAVCC = Min, VIH = MinVIL = 0.5V, IOH = Max

VOL

LOW Level Output Voltage

VCC = MinVIL = MaxVIH = Min

IOZHIOZLIIIIHIILIOSICC

Off-State Output Current,HIGH Level Voltage AppliedOff-State Output Current,LOW Level Voltage AppliedInput Current at MaximumInput Voltage

HIGH Level Input CurrentLOW Level Input CurrentShort Circuit Output CurrentSupply Current

VCC = Max

VI = 5.5VVI = 7V

VCC = Max, VI = 2.7VVCC = Max, VI = 0.4VVCC = Max (Note 4)VCC = MaxOutputsOPEN

Note 3: All typicals are at VCC = 5V, TA = 25°C.

Note 4: Not more than one output should be shorted at a time, and the duration should not exceed one second.

Conditions MinVCC = Min, II = −18 mAVCC = Min

0.22.72.42

Typ(Note 3)0.4

Max−1.5

UnitsVV

3.4V

IOL = 12 mAIOL = Max

0.4

V

0.540−200

A or BAny G

0.10.120−0.2

−40

222932

−225385054

mAµAµAmAmAµAmAmA

VCC = MaxVIL = MaxVIH = Min

VO = 2.7VVO = 0.4V

Outputs HIGHOutputs LOWOutputs Disabled

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DM74LS243Switching Characteristics

at VCC = 5V, TA = 25°C SymboltPLHtPHLtPZLtPZHtPLZtPHZtPLHtPHLtPZLtPZH

Parameter

Propagation Delay TimeLOW-to-HIGH Level OutputPropagation Delay TimeHIGH-to-LOW Level OutputOutput Enable Time to LOW LevelOutput Enable Time to HIGH LevelOutput Disable Timefrom LOW LevelOutput Disable Timefrom HIGH LevelPropagation Delay TimeLOW-to-HIGH Level OutputPropagation Delay TimeHIGH-to-LOW Level OutputOutput Enable Time to LOW LevelOutput Enable Time to HIGH Level

CL = 45 pFRL = 667ΩCL = 45 pFRL = 667ΩCL = 45 pFRL = 667ΩCL = 45 pFRL = 667ΩCL = 5 pFRL = 667ΩCL = 5 pFRL = 667ΩCL = 150 pFRL = 667ΩCL = 150 pFRL = 667ΩCL = 150 pFRL = 667ΩCL = 150 pFRL = 667Ω

Conditions

Min

Max18183023251821223326

Unitsnsnsnsnsnsnsnsnsnsns

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DM74LS243Physical Dimensions inches (millimeters) unless otherwise noted

14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-120, 0.150 Narrow

Package Number M14A

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DM74LS243 Quadruple Bus TransceiverPhysical Dimensions inches (millimeters) unless otherwise noted (Continued)

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

Package Number N14A

Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied andFairchild reserves the right at any time without notice to change said circuitry and specifications.LIFE SUPPORT POLICY

FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORTDEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILDSEMICONDUCTOR CORPORATION. As used herein:1.Life support devices or systems are devices or systemswhich, (a) are intended for surgical implant into thebody, or (b) support or sustain life, and (c) whose failureto perform when properly used in accordance withinstructions for use provided in the labeling, can be rea-sonably expected to result in a significant injury to theuser.

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2.A critical component in any component of a life supportdevice or system whose failure to perform can be rea-sonably expected to cause the failure of the life supportdevice or system, or to affect its safety or effectiveness.

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