Course Hero Logo

KEYPAD_DATASHEET.pdf - MM54C922/MM74C922 16-Key Encoder...

Course Hero uses AI to attempt to automatically extract content from documents to surface to you and others so you can study better, e.g., in search results, to enrich docs, and more. This preview shows page 1 - 3 out of 11 pages.

TLSLASHFSLASH6037MM54C922SLASHMM74C922 16-Key EncoderCOMMA MM54C923SLASHMM74C923 20-Key EncoderJuly 1993MM54C922SLASHMM74C922 16-Key EncoderMM54C923SLASHMM74C923 20-Key EncoderGeneral DescriptionThese CMOS key encoders provide all the necessary logicto fully encode an array of SPST switchesPERIOD The keyboardscan can be implemented by either an external clock orexternal capacitorPERIOD These encoders also have on-chip pull-up devices which permit switches with up to 50 kXon resist-ance to be usedPERIOD No diodes in the switch array are neededto eliminate ghost switchesPERIOD The internal debounce circuitneeds only a single external capacitor and can be defeatedby omitting the capacitorPERIOD A Data Available output goes to ahigh level when a valid keyboard entry has been madePERIOD TheData Available output returns to a low level when the en-tered key is releasedCOMMA even if another key is depressedPERIOD TheData Available will return high to indicate acceptance of thenew key after a normal debounce periodn53454d492d434f4c4f4e this two-key roll-over is provided between any two switchesPERIODAn internal register remembers the last key pressed evenafter the key is releasedPERIOD The TRI-STATEn454d2d554e44455253434f5245outputs providefor easy expansion and bus operation and are LPTTL com-patiblePERIODFeaturesY50 kXmaximum switch on resistanceYOn or off chip clockYOn-chip row pull-up devicesY2 key roll-overYKeybounce elimination with single capacitorYLast key register at outputsYTRI-STATE outpust LPTTL compatibleYWide supply range3V to 15VYLow power consumptionConnection DiagramsPin Assignment forDual-In-Line PackageTLSLASHFSLASH6037–1Top ViewOrder Number MM54C922 orMM74C922Pin Assignmentfor SOICTLSLASHFSLASH6037–14Top ViewOrder Number MM74C922Pin Assignment forDIP and SOIC PackageTLSLASHFSLASH6037–2Top ViewOrder Number MM54C923 orMM74C923TRI-STATEn454d2d554e44455253434f5245is a registered trademark of National Semiconductor CorporationPERIODC1995 National Semiconductor CorporationRRD-B30M105SLASHPrinted in UPERIOD SPERIOD APERIOD
Absolute Maximum Ratings(Note 1)If MilitarySLASHAerospace specified devices are requiredCOMMApleasecontacttheNationalSemiconductorSalesOfficeSLASHDistributors for availability and specificationsPERIODVoltage at Any PinVCCb0PERIOD3V to VCCa0PERIOD3VOperating Temperature RangeMM54C922COMMA MM54C923b55SNAKEC toa125SNAKECMM74C922COMMA MM74C923b40SNAKEC toa85SNAKECStorage Temperature Rangeb65SNAKEC toa150SNAKECPower Dissipation (PD)Dual-In-Line700 mWSmall Outline500 mWOperating VCCRange3V to 15VVCC18VLead Temperature(SolderingCOMMA 10 seconds)260SNAKECDC Electrical CharacteristicsMinSLASHMax limits apply across temperature range unless otherwise specifiedSymbolParameterConditionsMinTypMaxUnitsCMOS TO CMOSVTaPositive-Going Threshold VoltageVCCe5VCOMMA IINt0PERIOD7 mA3PERIOD03PERIOD64PERIOD3Vat Osc and KBM InputsVCCe10VCOMMA IINt1PERIOD4 mA6PERIOD06PERIOD88PERIOD6VVCCe15VCOMMA IINt2PERIOD1 mA9PERIOD01012PERIOD9VVTbNegative-Going Threshold VoltageVCCe5VCOMMA IINt0PERIOD7 mA0PERIOD71PERIOD42PERIOD0Vat Osc and KBM InputsVCCe10VCOMMA IINt1PERIOD4 mA1PERIOD43PERIOD24PERIOD0VVCCe15VCOMMA IINt2PERIOD1 mA2PERIOD156PERIOD0VVIN(1)Logical ‘‘1’’ Input VoltageCOMMAVCCe5V3PERIOD54PERIOD5VExcept Osc and KBM InputsVCCe10V8PERIOD09VVCCe15V12PERIOD513PERIOD5VVIN(0)Logical ‘‘0’’ Input VoltageCOMMAVCCe5V0PERIOD51PERIOD5VExcept Osc and KBM InputsVCCe10V12VVCCe15V1PERIOD52PERIOD5VIrpRow Pull-Up Current at Y1COMMA Y2COMMA

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 11 pages?

Upload your study docs or become a

Course Hero member to access this document

Term
Spring
Professor
N/A
Tags
Input output, KBM Inputs

Newly uploaded documents

Show More

Newly uploaded documents

Show More

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture