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

    74HCT646 Search Results

    74HCT646 Result Highlights (2)

    Part ECAD Model Manufacturer Description Download Buy
    SN74HCT646DW Texas Instruments Octal Bus Transceivers And Registers With 3-State Outputs 24-SOIC -40 to 85 Visit Texas Instruments Buy
    CD74HCT646M96 Texas Instruments High Speed CMOS Logic Octal Bus Transceivers/Registers with 3-State Outputs 24-SOIC -55 to 125 Visit Texas Instruments Buy
    SF Impression Pixel

    74HCT646 Price and Stock

    Rochester Electronics LLC SN74HCT646NT

    IC TXRX NON-INVERT 5.5V 24DIP
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey SN74HCT646NT Tube 10,190 278
    • 1 -
    • 10 -
    • 100 -
    • 1000 $1.08
    • 10000 $1.08
    Buy Now

    Rochester Electronics LLC SN74HCT646DW

    IC TXRX NON-INVERT 5.5V 24SOIC
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey SN74HCT646DW Bulk 6,179 351
    • 1 -
    • 10 -
    • 100 -
    • 1000 $0.86
    • 10000 $0.86
    Buy Now

    Rochester Electronics LLC CD74HCT646E

    IC TXRX NON-INVERT 5.5V 24DIP
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey CD74HCT646E Bulk 4,690 417
    • 1 -
    • 10 -
    • 100 -
    • 1000 $0.72
    • 10000 $0.72
    Buy Now

    Rochester Electronics LLC SN74HCT646DWR

    IC TXRX NON-INVERT 5.5V 24SOIC
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey SN74HCT646DWR Bulk 2,000 533
    • 1 -
    • 10 -
    • 100 -
    • 1000 $0.56
    • 10000 $0.56
    Buy Now

    Rochester Electronics LLC CD74HCT646M96

    IC TXRX NON-INVERT 5.5V 24SOIC
    Distributors Part Package Stock Lead Time Min Order Qty Price Buy
    DigiKey CD74HCT646M96 Bulk 2,000 183
    • 1 -
    • 10 -
    • 100 -
    • 1000 $1.64
    • 10000 $1.64
    Buy Now

    74HCT646 Datasheets (18)

    Part ECAD Model Manufacturer Description Curated Datasheet Type PDF
    74HCT646 Philips Semiconductors Octal bus transceiver/register, 3-state Original PDF
    74HCT646D Philips Semiconductors Octal bus transceiver/register 3-state Original PDF
    74HCT646D Unknown Historical semiconductor price guide (US$ - 1998). From our catalog scanning project. Historical PDF
    74HCT646D,652 NXP Semiconductors Octal bus transceiver/register; 3-state - Description: Transceiver/Register; TTL Enabled (3-State) ; Fmax: 85 MHz; Logic switching levels: TTL ; Number of pins: 24 ; Output drive capability: +/- 6 mA ; Power dissipation considerations: Low Power ; Propagation delay: 13 ns; Voltage: 4.5-5.5 V; Package: SOT137-1 (SO24); Container: Bulk Pack, CECC Original PDF
    74HCT646D,653 NXP Semiconductors Octal bus transceiver/register; 3-state - Description: Transceiver/Register; TTL Enabled (3-State) ; Fmax: 85 MHz; Logic switching levels: TTL ; Number of pins: 24 ; Output drive capability: +/- 6 mA ; Power dissipation considerations: Low Power ; Propagation delay: 13 ns; Voltage: 4.5-5.5 V; Package: SOT137-1 (SO24); Container: Reel Pack, SMD, 13", CECC Original PDF
    74HCT646DB Philips Semiconductors Octal bus transceiver/register 3-state Original PDF
    74HCT646DB Unknown Historical semiconductor price guide (US$ - 1998). From our catalog scanning project. Historical PDF
    74HCT646DB,112 NXP Semiconductors Octal bus transceiver/register; 3-state - Description: Transceiver/Register; TTL Enabled (3-State) ; Fmax: 85 MHz; Logic switching levels: TTL ; Number of pins: 24 ; Output drive capability: +/- 6 mA ; Power dissipation considerations: Low Power ; Propagation delay: 13 ns; Voltage: 4.5-5.5 V; Package: SOT340-1 (SSOP24); Container: Tube Original PDF
    74HCT646DB,118 NXP Semiconductors Octal bus transceiver/register; 3-state - Description: Transceiver/Register; TTL Enabled (3-State) ; Fmax: 85 MHz; Logic switching levels: TTL ; Number of pins: 24 ; Output drive capability: +/- 6 mA ; Power dissipation considerations: Low Power ; Propagation delay: 13 ns; Voltage: 4.5-5.5 V; Package: SOT340-1 (SSOP24); Container: Reel Pack, SMD, 13" Original PDF
    74HCT646DB-T NXP Semiconductors Octal bus transceiver/register; 3-state - Description: Transceiver/Register; TTL Enabled (3-State) ; Fmax: 85 MHz; Logic switching levels: TTL ; Number of pins: 24 ; Output drive capability: +/- 6 mA ; Power dissipation considerations: Low Power ; Propagation delay: 13 ns; Voltage: 4.5-5.5 V Original PDF
    74HCT646DB-T Unknown Historical semiconductor price guide (US$ - 1998). From our catalog scanning project. Historical PDF
    74HCT646D-T NXP Semiconductors Octal bus transceiver/register; 3-state - Description: Transceiver/Register; TTL Enabled (3-State) ; Fmax: 85 MHz; Logic switching levels: TTL ; Number of pins: 24 ; Output drive capability: +/- 6 mA ; Power dissipation considerations: Low Power ; Propagation delay: 13 ns; Voltage: 4.5-5.5 V Original PDF
    74HCT646D-T Unknown Historical semiconductor price guide (US$ - 1998). From our catalog scanning project. Historical PDF
    74HCT646N Philips Semiconductors Octal bus transceiver/register, 3-state Original PDF
    74HCT646N Unknown Historical semiconductor price guide (US$ - 1998). From our catalog scanning project. Historical PDF
    74HCT646N3 Philips Semiconductors Octal bus transceiver/register 3-state Original PDF
    74HCT646N,652 NXP Semiconductors Octal bus transceiver/register; 3-state - Description: Transceiver/Register; TTL Enabled (3-State) ; Fmax: 85 MHz; Logic switching levels: TTL ; Number of pins: 24 ; Output drive capability: +/- 6 mA ; Power dissipation considerations: Low Power ; Propagation delay: 13 ns; Voltage: 4.5-5.5 V; Package: SOT101-1 (DIP24); Container: Bulk Pack, CECC Original PDF
    74HCT646U Philips Semiconductors Octal bus transceiver/register 3-state Original PDF

    74HCT646 Datasheets Context Search

    Catalog Datasheet MFG & Type PDF Document Tags

    74HCT646

    Abstract: DIP-24 M74HCT646 M74HCT646B1R M74HCT646M1R M74HCT646RM13TR M74HCT646TTR SAB 16 pin dip switch
    Text: 74HCT646 OCTAL BUS TRANSCEIVER/REGISTER WITH 3 STATE OUTPUTS • ■ ■ ■ ■ ■ HIGH SPEED: fMAX = 60 MHz TYP. at VCC = 4.5V LOW POWER DISSIPATION: ICC = 4µA(MAX.) at TA=25°C COMPATIBLE WITH TTL OUTPUTS : VIH = 2V (MIN.) VIL = 0.8V (MAX) SYMMETRICAL OUTPUT IMPEDANCE:


    Original
    PDF M74HCT646 74HCT646 DIP-24 M74HCT646 M74HCT646B1R M74HCT646M1R M74HCT646RM13TR M74HCT646TTR SAB 16 pin dip switch

    74HC9046

    Abstract: 74hc128 74HCT4050 74HC1284 74hct133 74HCT4049 74HC7014 74hc164 74HC192 74HC93
    Text: INTEGRATED CIRCUITS Package information Supersedes data of 1999 Jul 09 File under Integrated Circuits, IC06 1999 Sep 22 Philips Semiconductors Package information PACKAGE INFORMATION PART NO DIP N SO (D) SSOP (DB) TSSOP (PW) PIN COUNT 74HCU04 27-1 108-1


    Original
    PDF 74HCU04 74HCTU04 74HC00 74HCT00 74HC02 74HCT02 74HC03 74HCT03 74HC04 74HCT04 74HC9046 74hc128 74HCT4050 74HC1284 74hct133 74HCT4049 74HC7014 74hc164 74HC192 74HC93

    k2638

    Abstract: 74HCT646 DIP-24 M74HCT646 M74HCT646B1R M74HCT646M1R M74HCT646RM13TR M74HCT646TTR P043A 1k26
    Text: 74HCT646 OCTAL BUS TRANSCEIVER/REGISTER WITH 3 STATE OUTPUTS • ■ ■ ■ ■ ■ HIGH SPEED: fMAX = 60 MHz TYP. at VCC = 4.5V LOW POWER DISSIPATION: ICC = 4µA(MAX.) at TA=25°C COMPATIBLE WITH TTL OUTPUTS : VIH = 2V (MIN.) VIL = 0.8V (MAX) SYMMETRICAL OUTPUT IMPEDANCE:


    Original
    PDF M74HCT646 74HCT646 k2638 DIP-24 M74HCT646 M74HCT646B1R M74HCT646M1R M74HCT646RM13TR M74HCT646TTR P043A 1k26

    5555 FAIRCHILD optocoupler

    Abstract: MC74HC374N 74hc14n equivalent NC7S125M5 14069 HCF4541BEY APPLICATION HCF4013BE 4026 fairchild datasheet 14543 motorola Motorola DM74LS139N
    Text: R E L I A B L E . L O G I C . I N N O V A T I O N . Logic Cross-Reference Logic Cross-Reference 2003 Texas Instruments Printed in the U.S.A. by Texoma Business Forms, Durant, Oklahoma Printed on recycled paper. SCYB017A NEW First Revision Logic Cross-Reference


    Original
    PDF SCYB017A A010203 5555 FAIRCHILD optocoupler MC74HC374N 74hc14n equivalent NC7S125M5 14069 HCF4541BEY APPLICATION HCF4013BE 4026 fairchild datasheet 14543 motorola Motorola DM74LS139N

    74HC9046

    Abstract: 74HCT4050 74hct7014 74HCT4049 74HC7541 74hct133 74HC9046A 74HC90 74HCT4059 74HC5555
    Text: INTEGRATED CIRCUITS Package information Supersedes data of 2001 Nov 02 File under Integrated Circuits, IC06 Philips Semiconductors 2002 Aug 08 Philips Semiconductors Package information PACKAGE INFORMATION PART NUMBER DIL N SO (D) SSOP (DB) TSSOP (PW) PIN COUNT


    Original
    PDF 74HCU04 74HCTU04 74HC00 74HCT00 74HC02 74HCT02 74HC03 74HCT03 74HC04 74HC86 74HC9046 74HCT4050 74hct7014 74HCT4049 74HC7541 74hct133 74HC9046A 74HC90 74HCT4059 74HC5555

    k2645

    Abstract: k4005 U664B mosfet k4005 MB8719 transistor mosfet k4004 SN16880N stk5392 STR451 BC417
    Text: 1 BHIAB Electronics Du som söker besvärliga IC & transistorer, börja Ditt sökande hos oss – vi har fler typer på lager än man rimlingen kan begära av ett företag Denna utgåva visar lagerartiklar men tyvärr saknas priser och viss information Men uppdatering sker kontinuerligt


    Original
    PDF MK135 MK136 MK137 MK138 MK139 MK140 Mk142 MK145 MK155 157kr k2645 k4005 U664B mosfet k4005 MB8719 transistor mosfet k4004 SN16880N stk5392 STR451 BC417

    SKIIP 33 nec 125 t2

    Abstract: skiip 613 gb 123 ct RBS 6302 ericsson SKIIP 513 gb 173 ct THERMISTOR ml TDK 150M pioneer PAL 010a Project Report of smoke alarm using IC 555 doc SKiip 83 EC 125 T1 ericsson RBS 6000 series INSTALLATION MANUAL Ericsson Installation guide for RBS 6302
    Text: Discontinued and Superseded Stock Number History. This document contains Discontinued and Superseded Stock Number History. The information is listed in the following format: Stock Number: The original RS Stock Number of the item. Brief Description: The Invoice Description of the item.


    Original
    PDF 734TL UWEB-MODEM-34 HCS412/WM TLV320AIC10IPFB 100MB NEON250 GA-60XM7E BLK32X40 BLK32X42 SKIIP 33 nec 125 t2 skiip 613 gb 123 ct RBS 6302 ericsson SKIIP 513 gb 173 ct THERMISTOR ml TDK 150M pioneer PAL 010a Project Report of smoke alarm using IC 555 doc SKiip 83 EC 125 T1 ericsson RBS 6000 series INSTALLATION MANUAL Ericsson Installation guide for RBS 6302

    CMOS IC MANUAL

    Abstract: ceramic resonator c28 MAX232 pin configuration 5 VOLT piezo beeper LT1181 2n5088 alternative resonator c28 pin configuration transistor 2n2907 161x bar code reader
    Text: Single Chip Bar Code Decode IC Technical Data HBCR-1610 HBCR-1611 HBCR-1612 Features • Supports Five Industry Standard Bar Code Symbologies • Automatic Code Recognition • Choice of Parallel or Full Duplex Serial ASCII Interface • Programmable via Escape


    Original
    PDF HBCR-1610 HBCR-1611 HBCR-1612 5965-5950E 5968-2201E CMOS IC MANUAL ceramic resonator c28 MAX232 pin configuration 5 VOLT piezo beeper LT1181 2n5088 alternative resonator c28 pin configuration transistor 2n2907 161x bar code reader

    74HC4053D

    Abstract: HEF40106BP 74hc161 application notes 74HC154N3 74HC244D 74HCT125D HEF4007UBP 74HC163 74HC00D HEF40097BP
    Text: Exh C - Att: 3 CLARIFICATION LIST OF LOGIC BURN-IN PARTS FROM DN-41, DATED JUNE 30, 1999 PHILIPS PART NUMBER PHILIPS PKG PHILIPS PART DESCRIPTION 74HC00 74HC00D/S15 74HC02 74HC08 74HC125 74HC132 74HC154N3 74HC161 74HC163 74HC165 74HC174 74HC20N/S15 74HC21


    Original
    PDF DN-41, 74HC00 74HC00D/S15 74HC02 74HC08 74HC125 74HC132 74HC154N3 74HC161 74HC163 74HC4053D HEF40106BP 74hc161 application notes 74HC154N3 74HC244D 74HCT125D HEF4007UBP 74HC163 74HC00D HEF40097BP

    ceramic resonator c28

    Abstract: cdb 442 piezo beeper 74HCT574 ceramic resonator CDB c28 1N4148 2N2907 2N5088 74HCT646 HBCR-1610
    Text: H Single Chip Bar Code Decode IC Technical Data HBCR-1610 HBCR-1611 HBCR-1612 Features • Supports Five Industry Standard Bar Code Symbologies • Automatic Code Recognition • Choice of Parallel or Full Duplex Serial ASCII Interface • Programmable via Escape


    Original
    PDF HBCR-1610 HBCR-1611 HBCR-1612 ceramic resonator c28 cdb 442 piezo beeper 74HCT574 ceramic resonator CDB c28 1N4148 2N2907 2N5088 74HCT646 HBCR-1610

    BUK2114

    Abstract: BUK2114-50SYTS saa7117 SAA7136E MPSA92 168 saa7136 buk2914-50syts TDA8920BTH bu4508dx KMZ52
    Text: Index Type number Page number 1N4148 34 1N4531 34 1N47xxA series 44 1PS10SB62 32 1PS10SB63 32 1PS10SB82 32 1PS181 36 1PS184 36 1PS193 34 1PS226 36 1PS59SB10 28 1PS59SB14 28 1PS59SB15 28 1PS59SB16 28 1PS59SB20 30 1PS59SB21 28 1PS66SB17 32 1PS66SB62 32 1PS66SB63


    Original
    PDF 1N4148 1N4531 1N47xxA 1PS10SB62 1PS10SB63 1PS10SB82 1PS181 1PS184 1PS193 1PS226 BUK2114 BUK2114-50SYTS saa7117 SAA7136E MPSA92 168 saa7136 buk2914-50syts TDA8920BTH bu4508dx KMZ52

    Untitled

    Abstract: No abstract text available
    Text: r z j S G S -T H O M S O N RiöO g^(ö [ILi K!lö(gi M54/74HCT646 M54/74HCT648 HCT646 OCTAL BUS TRANSCEIVER/REGISTER (3-STATE) HCT648 OCTAL BUS TRANSCEIVER/REGISTER (INVERTING-3 STATE) • LOW POWER DISSIPATION lCc = 4itA (MAX.) at TA = 25°C ■ COMPATIBLE WITH TTL OUTPUTS


    OCR Scan
    PDF M54/74HCT646 M54/74HCT648 HCT646 HCT648 54/74LS646/648 M54/74HCT646/648 M54/74HCT646/648

    Untitled

    Abstract: No abstract text available
    Text: Technical Data CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 File Number 1664 . Texas . HlQ n"SPfiC ti . • LOCI 1C In s tr u m e n ts Data sheet acquired from Harris Semiconductor SCHS278 Octal Bus Transceiver/Register, 3-State Type Features:


    OCR Scan
    PDF CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 SCHS278 54/74H 15LSTTL

    92CS-30329

    Abstract: 74HC-HCT646 74hct648
    Text: Technical Data CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 File N u m be r 1664 Te x a s m . . H lQ n " S P ^ ^ tt ^9 . In s tru m e n ts L O G IC I Data sheet acquired from H arris S em iconductor S C HS278 Octal Bus Transceiver/Register, 3-State


    OCR Scan
    PDF CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 SCHS278 92CS-30329 CD54/74HC/HCT646 CD54/74HC/HCT648 15LSTTL RCA-CD54/74HC646 74HC-HCT646 74hct648

    Untitled

    Abstract: No abstract text available
    Text: Technical Data CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 File N um ber 1664 Ad, . „ c . Preliminary Data High-Speed CMOS Logic Octal Bus Transceiver/Register, 3-State Type Features: Ic b a c l o c k SOURCE I*«SOURCE SELECTION tSBA SOURCE


    OCR Scan
    PDF CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 CD54/74HC/HCT646 54/74HC/HCT648 15LSTTL 54/74H

    Untitled

    Abstract: No abstract text available
    Text: Æ T S G S-T H O M S O N ^ 7 Mu iM m ig T T M O ig S M54/74HCT646 M54/74HCT648 HCT646 OCTAL BUS TRANSCEIVER/REGISTER 3-STATE HCT648 OCTAL BUS TRANSCEIVER/REGISTER (INVERTING-3 STATE) • LOW POWER DISSIPATION lcc = 4MA (MAX.) at TA = 25°C ■ COMPATIBLE WITH TTL OUTPUTS


    OCR Scan
    PDF M54/74HCT646 M54/74HCT648 HCT646 HCT648 54/74LS646/648 M54/74HCT646/648 M54/74HCT646/648 105S2

    Untitled

    Abstract: No abstract text available
    Text: 5 bE 7 T 2 ‘ì S 3 7 ]} GDMDEÔS Ô7b « S 6 T H V -5 2 - 3 0 - 0 7 M54/74HCT646 M54/74HCT648 SGS-THOMSON HCT646 OCTAL BUS TRANSCEIVER/REGISTER 3-STATE HCT648 OCTAL BUS TRANSCEIVER/REGISTER (INVERTING-3 STATE) S Û S-THOMSON • LOW POWER DISSIPATION |c c = 4/iA (MAX.) at TA = 250C


    OCR Scan
    PDF M54/74HCT646 M54/74HCT648 HCT646 HCT648 54/74LS646/648 M54/74HCT646/648 M54/74HCT646/648

    54HC646

    Abstract: No abstract text available
    Text: Technical Data CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 File Number 1664 . Texas . . H lQ n " S P fiC t i • In s tr u m e n ts L O C I 1C Data sheet acquired from Harris Sem iconductor SC HS278 Octal Bus Transceiver/Register, 3-State Type Features:


    OCR Scan
    PDF CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 HS278 CD54/74HC/HCT646 CD54/74HC/HCT648 15LSTTL 54HC646

    74hct646

    Abstract: 74hc648 74hct648
    Text: T - S T Technical Data. CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 s -’ò I - O O File Number 1664 Advance Information/ Preliminary Data High-Speed CMOS Logic HARRIS SEMICOND SECTOR 5?E » 43G2271 QQ17ÔS1 7 S H A S Octal Bus Transceiver/Register,


    OCR Scan
    PDF CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 43G2271 CD54/74HC/HCT646 CD54/74HC/HCT648 15LSTTL RCA-CD54/74HC646 74hct646 74hc648 74hct648

    Untitled

    Abstract: No abstract text available
    Text: Technical Data CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 File N um ber 1664 Ad ,„ „ c . m o n » .« , Preliminary Data High-Speed CMOS Logic Octal Bus Transceiver/Register, 3-State Type Features: FU N C TIO N A L DIAGRAM i Independent Registers lo r


    OCR Scan
    PDF CD54/74HC646, CD54/74HCT646 CD54/74HC648, CD54/74HCT648 CD54/74HC/HCT646 CD54/74HC/HCT648 15LSTTL 54/74H

    74ls646

    Abstract: M74HCT646
    Text: / HS-C MOS” ' ' INTEGRATED CIRCUITS PRODUCT PREVIEW OCTAL BUS TRANSCEIVERS AND REGISTERS, 3-STATE DESCRIPTION The M 54/74HCT646 is a high speed CM OS OC­ TAL BUS TRAN SCEIVERS AND REGISTERS, fabricated in silicon gate C2MOS technology. It has the sam e high speed perform ance of LSTTL,


    OCR Scan
    PDF M54/74HCT646 M54HCT646 M74HCT646 54/74LS646 74ls646

    BCR161

    Abstract: No abstract text available
    Text: WÜKM E S I HEW LETT PACKARD NOV 3 0 19tt Single Chip Bar Code D ecode IC H B C R -1 6 1 0 Technical Data F eatu res • Supports 5 Industry Standard B ar Code S ym b ologies • A u tom atic Code R eco g n itio n • C h oice o f P a ra llel or Full D uplex S erial ASCII


    OCR Scan
    PDF HBCR-1610 HBCR-1612 5091-4572E BCR161

    HBCR-1697

    Abstract: LT1181 HBCR-1612 cdb c28 ceramic resonator CDB c28 hbcr1611
    Text: W/j'jm HEWLETT m!lim P A C K A R D Single Chip Bar Code Decode IC Technical Data HBCR-1610 HBCR-1611 HBCR-1612 Features • Supports Five Industry Standard Bar Code Symbologies • Automatic Code Recognition • Choice o f Parallel or Full Duplex Serial ASCII


    OCR Scan
    PDF HBCR-1610 HBCR-1611 HBCR-1612 HBCR-1611 5965-5950E 5968-2201E HBCR-1697 LT1181 HBCR-1612 cdb c28 ceramic resonator CDB c28 hbcr1611

    74hct646

    Abstract: MB946
    Text: Ü 2Î S S Ï S Î S S G S -T U O M S O N M 74H C T648 HCT646 OCTAL BUS TRANSCEIVER/REGISTER 3-STATE HCT648 OCTAL BUS TRANSCEIVER/REGISTER (3-STATE, INV.) • HIGH SPEED fMAX = 60 MHz (TYP.) AT V cc = 5 V ■ LOW POWER DISSIPATION Ice = 4 |iA (MAX.) AT T a = 25 ‘C


    OCR Scan
    PDF HCT646 HCT648 54/74LS646/648 M74HCT646/648 HCT648 74HCT646/648 74hct646 MB946