Please enter a valid full or partial manufacturer part number with a minimum of 3 letters or numbers

    SN74LS642 Search Results

    SN74LS642 Result Highlights (5)

    Part ECAD Model Manufacturer Description Download Buy
    SN74LS642DW Texas Instruments Octal bus transceivers with open collector outputs 20-SOIC 0 to 70 Visit Texas Instruments Buy
    SN74LS642-1N Texas Instruments Octal bus transceivers with open collector outputs 20-PDIP 0 to 70 Visit Texas Instruments Buy
    SN74LS642-1DW Texas Instruments Octal bus transceivers with open collector outputs 20-SOIC 0 to 70 Visit Texas Instruments Buy
    SN74LS642NSR Texas Instruments Octal bus transceivers with open collector outputs 20-SO 0 to 70 Visit Texas Instruments Buy
    SN74LS642N Texas Instruments Octal bus transceivers with open collector outputs 20-PDIP 0 to 70 Visit Texas Instruments Buy
    SF Impression Pixel

    SN74LS642 Price and Stock

    Rochester Electronics LLC SN74LS642-1DW

    SN74LS642 OCTAL BUS TRANSCEIVERS
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey SN74LS642-1DW Bulk 8,828 65
    • 1 -
    • 10 -
    • 100 $4.63
    • 1000 $4.63
    • 10000 $4.63
    Buy Now

    Texas Instruments SN74LS642DW

    IC TXRX INVERT 5.25V 20SOIC
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey SN74LS642DW Tube 70 1
    • 1 $5.42
    • 10 $4.895
    • 100 $4.053
    • 1000 $4.00876
    • 10000 $4.00876
    Buy Now
    Mouser Electronics SN74LS642DW 343
    • 1 $5.42
    • 10 $4.9
    • 100 $4
    • 1000 $4
    • 10000 $4
    Buy Now
    Verical SN74LS642DW 68 2
    • 1 -
    • 10 $0.7474
    • 100 $0.7474
    • 1000 $0.7474
    • 10000 $0.7474
    Buy Now
    Arrow Electronics SN74LS642DW 75 12 Weeks 25
    • 1 -
    • 10 -
    • 100 $3.702
    • 1000 $3.702
    • 10000 $3.702
    Buy Now
    SN74LS642DW 68 12 Weeks 1
    • 1 $0.7474
    • 10 $0.7474
    • 100 $0.7474
    • 1000 $0.7474
    • 10000 $0.7474
    Buy Now
    Bristol Electronics SN74LS642DW 50
    • 1 -
    • 10 -
    • 100 -
    • 1000 -
    • 10000 -
    Get Quote
    SN74LS642DW 21
    • 1 -
    • 10 -
    • 100 -
    • 1000 -
    • 10000 -
    Get Quote
    SN74LS642DW 15
    • 1 -
    • 10 -
    • 100 -
    • 1000 -
    • 10000 -
    Get Quote
    Quest Components SN74LS642DW 70
    • 1 $12.1533
    • 10 $8.1022
    • 100 $7.4945
    • 1000 $7.4945
    • 10000 $7.4945
    Buy Now
    SN74LS642DW 16
    • 1 $8.955
    • 10 $6.567
    • 100 $5.97
    • 1000 $5.97
    • 10000 $5.97
    Buy Now
    SN74LS642DW 12
    • 1 $10.02
    • 10 $7.348
    • 100 $6.68
    • 1000 $6.68
    • 10000 $6.68
    Buy Now
    Rochester Electronics SN74LS642DW 6,901 1
    • 1 $4.68
    • 10 $4.68
    • 100 $4.4
    • 1000 $3.98
    • 10000 $3.98
    Buy Now
    Chip1Stop SN74LS642DW 325
    • 1 -
    • 10 -
    • 100 $3.83
    • 1000 $3.83
    • 10000 $3.83
    Buy Now
    SN74LS642DW 68
    • 1 $4.71
    • 10 $4.71
    • 100 $4.71
    • 1000 $4.71
    • 10000 $4.71
    Buy Now

    Texas Instruments SN74LS642N

    IC TXRX INVERT 5.25V 20DIP
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey SN74LS642N Tube 8 1
    • 1 $10.02
    • 10 $10.02
    • 100 $7.495
    • 1000 $5.68443
    • 10000 $5.68443
    Buy Now
    Mouser Electronics SN74LS642N 34
    • 1 $10.02
    • 10 $8.92
    • 100 $6.89
    • 1000 $5.62
    • 10000 $5.62
    Buy Now
    Bristol Electronics SN74LS642N 14
    • 1 -
    • 10 -
    • 100 -
    • 1000 -
    • 10000 -
    Get Quote
    Quest Components SN74LS642N 3
    • 1 $11.8184
    • 10 $11.0305
    • 100 $11.0305
    • 1000 $11.0305
    • 10000 $11.0305
    Buy Now
    Rochester Electronics SN74LS642N 3,318 1
    • 1 $6.08
    • 10 $6.08
    • 100 $5.72
    • 1000 $5.17
    • 10000 $5.17
    Buy Now
    Chip 1 Exchange SN74LS642N 134
    • 1 -
    • 10 -
    • 100 -
    • 1000 -
    • 10000 -
    Get Quote
    Chip1Stop SN74LS642N Tube 40
    • 1 $9.21
    • 10 $8.2
    • 100 $8.1
    • 1000 $8.1
    • 10000 $8.1
    Buy Now

    Texas Instruments SN74LS642-1DW

    IC TXRX INVERT 5.25V 20SOIC
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey SN74LS642-1DW Tube 1 1
    • 1 $7.71
    • 10 $7.71
    • 100 $7.71
    • 1000 $7.71
    • 10000 $7.71
    Buy Now
    Mouser Electronics SN74LS642-1DW
    • 1 -
    • 10 -
    • 100 -
    • 1000 $5.55
    • 10000 $5.55
    Get Quote
    Rochester Electronics SN74LS642-1DW 8,828 1
    • 1 $4.68
    • 10 $4.68
    • 100 $4.4
    • 1000 $3.98
    • 10000 $3.98
    Buy Now

    Texas Instruments SN74LS642NS

    PROTOTYPE
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey SN74LS642NS Tube
    • 1 -
    • 10 -
    • 100 -
    • 1000 -
    • 10000 -
    Buy Now

    SN74LS642 Datasheets (94)

    Part ECAD Model Manufacturer Description Curated Type PDF
    SN74LS642 Motorola OCTAL BUS TRANSCEIVERS Original PDF
    SN74LS642 On Semiconductor Octal Bus Transceivers Original PDF
    SN74LS642 Texas Instruments OCTAL BUS TRANSCEIVERS Original PDF
    SN74LS642-1 Texas Instruments Octal Bus Transceivers with Open-Collector Outputs Original PDF
    SN74LS642-1DW Texas Instruments SN74LS642 - Octal bus transceivers with open collector outputs 20-SOIC 0 to 70 Original PDF
    SN74LS642-1DW Texas Instruments OCTAL BUS TRANSCEIVERS WITH OPEN COLLECTOR OUTPUTS Original PDF
    SN74LS642-1DW Texas Instruments Octal bus transceivers with open collector outputs 20-SOIC 0 to 70 Original PDF
    SN74LS642-1DW Texas Instruments Logic - Buffers, Drivers, Receivers, Transceivers, Integrated Circuits (ICs), IC BUS TRANSCEIVER 8BIT 20SOIC Original PDF
    SN74LS642-1DW Unknown Historical semiconductor price guide (US$ - 1998). From our catalog scanning project. Historical PDF
    SN74LS642-1DWE4 Texas Instruments SN74LS642 - Octal bus transceivers with open collector outputs 20-SOIC 0 to 70 Original PDF
    SN74LS642-1DWE4 Texas Instruments Octal bus transceivers with open collector outputs 20-SOIC 0 to 70 Original PDF
    SN74LS642-1DWE4 Texas Instruments Octal bus transceivers with open collector outputs Original PDF
    SN74LS642-1DWE4 Texas Instruments Logic - Buffers, Drivers, Receivers, Transceivers, Integrated Circuits (ICs), IC BUS TRANSCEIVER 8BIT 20SOIC Original PDF
    SN74LS642-1DWG4 Texas Instruments SN74LS642 - Octal bus transceivers with open collector outputs 20-SOIC 0 to 70 Original PDF
    SN74LS642-1DWG4 Texas Instruments Octal bus transceivers with open collector outputs 20-SOIC 0 to 70 Original PDF
    SN74LS642-1DWG4 Texas Instruments Logic - Buffers, Drivers, Receivers, Transceivers, Integrated Circuits (ICs), IC BUS TRANSCEIVER 8BIT 20SOIC Original PDF
    SN74LS642-1DWR Texas Instruments SN74LS642 - IC LS SERIES, 8-BIT TRANSCEIVER, INVERTED OUTPUT, PDSO20, SO-20, Bus Driver/Transceiver Original PDF
    SN74LS642-1FN Texas Instruments SN74LS642 - IC LS SERIES, 8-BIT TRANSCEIVER, INVERTED OUTPUT, PQCC20, Bus Driver/Transceiver Original PDF
    SN74LS642-1FNR Texas Instruments SN74LS642 - IC LS SERIES, 8-BIT TRANSCEIVER, INVERTED OUTPUT, PQCC20, Bus Driver/Transceiver Original PDF
    SN74LS642-1J Texas Instruments SN74LS642 - IC LS SERIES, 8-BIT TRANSCEIVER, INVERTED OUTPUT, CDIP20, Bus Driver/Transceiver Original PDF

    SN74LS642 Datasheets Context Search

    Catalog Datasheet MFG & Type PDF Document Tags

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    Sn74ls641

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189 Sn74ls641

    Untitled

    Abstract: No abstract text available
    Text: SN74LS640, SN74LS641, SN74LS642, SN74LS645 Octal Bus Transceivers These octal bus transceivers are designed for asynchronous two-way communication between data buses. Control function implementation minimizes external timing requirements. These circuits allow data transmission from the A bus to B or from the B bus


    Original
    PDF SN74LS640, SN74LS641, SN74LS642, SN74LS645 LS640 LS641 LS642 LS645 SN74LS64xN

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    SN74LS642

    Abstract: LS640 LS641 LS642 LS645 SN74LS640 SN74LS640N SN74LS641 SN74LS645
    Text: SN74LS640, SN74LS641, SN74LS642, SN74LS645 Octal Bus Transceivers These octal bus transceivers are designed for asynchronous two-way communication between data buses. Control function implementation minimizes external timing requirements. These circuits allow data transmission from the A bus to B or from the B bus


    Original
    PDF SN74LS640, SN74LS641, SN74LS642, SN74LS645 LS640 LS641 LS642 LS645 SN74LS64xN r14525 SN74LS642 LS640 LS641 LS642 LS645 SN74LS640 SN74LS640N SN74LS641 SN74LS645

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    Texas Instruments Logic Guide

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189 Texas Instruments Logic Guide

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    sn74ls641n

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189 sn74ls641n

    SN74LS640

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    LS640

    Abstract: LS641 LS642 LS645 SN74LS640 SN74LS641 SN74LS642 SN74LS645
    Text: SN74LS640, SN74LS641, SN74LS642, SN74LS645 Octal Bus Transceivers These octal bus transceivers are designed for asynchronous two-way communication between data buses. Control function implementation minimizes external timing requirements. These circuits allow data transmission from the A bus to B or from the B bus


    Original
    PDF SN74LS640, SN74LS641, SN74LS642, SN74LS645 LS640 LS641 LS642 LS645 SN74LS64xN r14525 LS640 LS641 LS642 LS645 SN74LS640 SN74LS641 SN74LS642 SN74LS645

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    SN54LS640

    Abstract: SN54LS641 SN54LS642 SN54LS644 SN54LS645 SN74LS640 SN74LS642 SN74LS644 SN74LS645
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189 SN54LS641 SN54LS642 SN54LS644 SN54LS645 SN74LS642 SN74LS644 SN74LS645

    SN54LS640

    Abstract: SN54LS641 SN54LS642 SN54LS644 SN54LS645 SN74LS640 SN74LS642 SN74LS644 SN74LS645 SN74LS641N
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189 SN54LS641 SN54LS642 SN54LS644 SN54LS645 SN74LS642 SN74LS644 SN74LS645 SN74LS641N

    SNJ54LS

    Abstract: SN74LS641N ls641-1 74LS642
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189 SNJ54LS SN74LS641N ls641-1 74LS642

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVRS SDLS189 – APRIL 1979 – REVISED MARCH 1988 Copyright  1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date.


    Original
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 SDLS189

    Untitled

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644, SN54LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVERS 02420, APRIL 1979-REVISED MARCH 1988 SN 5 4 L S ' . . . J PA C KA G E S N 7 4 L S ' . . . D W OR N P A C K A G E SN74LS64X-1 Versions Rated at I q L


    OCR Scan
    PDF SN54LS640 SN54LS642, SN54LS644, SN54LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 1979-REVISED SN74LS64X-1

    54ls640

    Abstract: No abstract text available
    Text: SN54LS640 THRU SN54LS642, SN54LS644. SNS4LS645 SN74LS640 THRU SN74LS642, SN74LS644, SN74LS645 OCTAL BUS TRANSCEIVERS D2420, APRIL 1979-REV1SED MARCH 1988 SN54LS' . . . J PACKAGE SN 74LS' . . . DW OR N PACKAGE SN74LS04X-1 Versions Rated at I qj_ of 48 mA TOP VIEW


    OCR Scan
    PDF SN54LS640 SN54LS642, SN54LS644. SNS4LS645 SN74LS640 SN74LS642, SN74LS644, SN74LS645 D2420, 1979-REV1SED 54ls640