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OE

CK

I1

I0

CI

D7–D0

Q7–Q0

Operation

HLLLLL

X

uuuu

u

XLLHHH

XLHLHH

XXXXHL

XXXDXX

ZLQDQ

Qplus1

HI-ZCLEARHOLDLOADHOLD

INCREMENT

July1989

DM54LS461/DM74LS461OctalCounter

GeneralDescription

TheLS461isan8-bitsynchronouscounterwithparallelload,clear,andholdcapability.Twofunctionselectinputs(I0,I1)proneoffouroperationswhichoccursynchro-

nouslyontherisingedgeoftheclock(CK).

TheLOADoperationloadstheinputs(D7–D0)intotheout-putregister(Q7–Q0).TheCLEARoperationresetstheout-putregistertoallLOWs.TheHOLDoperationholdsthepreviousvalueregardlessofclocktransitions.TheINCRE-MENToperationaddsonetotheoutputregisterwhenthecarry-ininputisTRUE(CILOW),otherwisetheoperationisaHOLD.Thecarry-out(CO)isTRUE(COLOW)whentheoutputregister(Q7–Q0)isallHIGHs,otherwiseFALSE(COHIGH).

Theoutputregister(Q7–Q0)isenabledwhenOEisLOW,anddisabled(HI-Z)whenOEisHIGH.Theoutputdriverswillsinkthe24mArequiredformanybusinterfacestand-ards.

TwoormoreLS461octalcountersmaybecascadedto

providelargercounters.TheoperationcodeswerechosensuchthatwhenI1isHIGH,I0maybeusedtoselectbe-tweenLOADandINCREMENTasinaprogramcounter(JUMP/INCREMENT).

Features/Benefits

YOctalcounterformicroprogram-counter,DMAcontrollerandgeneralpurposecountingapplications

Y8bitsmatchbyteboundaries

YBus-structuredpinout

Y24-pinSkinnyDipsavesspace

YTRI-STATEéoutputsdrivebuslines

YLowcurrentPNPinputsreduceloading

YExpandablein8-bitincrements

ConnectionDiagram

StandardTestLoad

TopView

TL/L/83342

TL/L/83341

OrderNumberDM54LS461J,DM74LS461JorDM74LS461N

SeeNSPackageNumberJ24ForN24C

FunctionTable

TRISTATEéisa

ofNationalSemiconductorCorp

DM54LS461/DM74LS461OctalCounter

C1995NationalSemiconductorCorporation

TL/L/8334

RRDB30M115/PrintedinUSA

Absolute umRatings

IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheNationalSemiconductorSalesOffice/Distributorsforavailabilityandspecifications.

SupplyVoltageVCC 7V

InputVoltage 5.5V

OperatingConditions

Off-StateOutputVoltage 5.5V

StorageTemperature b65§Ctoa150§C

Symbol

Parameter

Military

Commercial

Units

Min

Typ

Max

Min

Typ

Max

VCC

SupplyVoltage

4.5

5

5.5

4.75

5

5.25

V

TA

Operating-AirTemperature

b55

125*

0

75

§C

tW

WidthofClock

Low

40

35

ns

High

30

25

tSU

SetUpTime

60

50

ns

th

HoldTime

0

b15

0

b15

*CaseTemperature

ElectricalCharacteristicsOverOperatingConditions

Symbol

Parameter

TestConditions

Min

Typ2

Max

Units

VIL

Low-LevelInputVoltage

0.8

V

VIH

High-LevelInputVoltage

2

V

VIC

InputClampVoltage

VCC

MIN

II

b18mA

b1.5

V

IIL

Low-LevelInputCurrent

VCC

MAX

VI0.4V

b0.25

mA

IIH

High-LevelInputCurrent

VCC

MAX

VI2.4V

25

mA

II

umInputCurrent

VCC

MAX

VI5.5V

1

mA

VOL

Low-LevelOutputVoltage

VCCMIN

VIL0.8V

MIL IOL12mA

0.5

V

VIH2V

COM IOL24mA

VOH

High-LevelOutputVoltage

VCCMIN

VIL0.8V

MIL IOHb2mA

2.4

V

VIH2V

COM IOHb3.2mA

IOZL

Off-StateOutputCurrent

VCCMAX

VIL0.8V

VIH2V

VO0.4V

b100

mA

IOZH

VO2.4V

100

mA

IOS

OutputShort-CircuitCurrent*

VCC

5.0V

VCC0V

b30

b130

mA

ICC

SupplyCurrent

VCC

MAX

120

180

mA

*Nomorethanoneoutputshouldbeshortedatatimeanddurationoftheshort-circuitshouldnotexceedonesecond

2AlltypicalvaluesareatVCC5V,TA25§C.

SwitchingCharacteristicsOverOperatingConditions

Symbol

Parameter

TestConditions(SeeTestLoad)

Military

Commercial

Units

Min

Typ

Max

Min

Typ

Max

fMAX

umClockFrequency

CL50pF

R1200X

R2390X

10.5

12.5

MHz

tPD

CBItoCBODelay

35

60

35

50

ns

tPD

ClocktoQ

20

35

20

30

ns

tPD

ClocktoCO

55

95

55

80

ns

tPZX

OutputEnableDelay

35

55

35

45

ns

tPXZ

OutputDisableDelay

35

55

35

45

ns

2

LogicDiagram

LS461

TL/L/83343

3

DM54LS461/DM74LS461OctalCounter

PhysicalDimensionsinches(millimeters)

24-PinNarrowCeramicDual-In-LinePackage(J)

OrderNumberDM54LS461JorDM74LS461JNSPackageJ24F

LIFESUPPORT

24-PinNarrow sticDual-In-LinePackage(N)

OrderNumberDM74LS461NNSPackageN24C

NATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORT

DEVICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHE OFNATIONALSEMICONDUCTORCORPORATION.Asusedherein:

1.Lifesupportdevicesorsystemsaredevicesor2.Acriticalcomponentisanycomponentofalifesystemswhich,(a)areintendedforsurgicalimntsupportdeviceorsystemwhosefailuretoperformcanintothebody,or(b)supportorsustainlife,andwhosebereasonablyexpectedtocausethefailureofthelifefailuretoperform,whenproperlyusedinaccordancesupportdeviceorsystem,ortoaffectitssafetyorwithinstructionsforuseprovidedinthelabeling,caneffectiveness.

bereasonablyexpectedtoresultinasignificantinjurytotheuser.

NationalSemiconductor

Corporation

1111WestBardinRoadArlington,TX76017

:1(800)272-9959

Fax:1(800)737-7018

NationalSemiconductor

Europe

Fax:(a49)0-180-5308586

:cn

Deutsch :(a49)0-180-5308585

English :(a49)0-180-5327832

Fran3ais:(a49)0-180-5329358

NationalSemiconductor

13thFloor,StraightBlock,OceanCentre,5CantonRd.Tsimshatsui,

NationalSemiconductor

Japan.

:81-

Fax:81-

I

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