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74_646 - Octal Transceiver/Register

Octal Transceiver/Register with 3-STATE Outputs 74F646SPC

These devices consist of bus transceiver circuits with 3-STATE, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the input bus or from the internal registers. Data on the A or B bus will be clocked into the registers as the appropriate clock pin goes to a high logic level. Control G and direction pins are provided to control the transceiver function. In the transceiver mode, data present at the high impedance port may be stored in either the A or the B register or in both. The select controls can multiplex stored and real-time (transparent mode) data. The direction control determines which bus will receive data when the enable control G is Active LOW. In the isolation mode (control G HIGH), A data may be stored in the B register and/or B data may be stored in the A register.


  • Independent registers for A and B buses
  • Multiplexed real-time and stored data
  • 74F646 has non-inverting data paths
  • 3-STATE outputs


Pinout 74F646

at the Amiga

TypCommo-No. C= Description C= Info Form Editors Info
A 380230-05IC 74ALS646
C 390281-01IC TTL 74F646A2620, A3000, PC-60(3)DIP-24
D 390616-01IC TTL 74AS646A2620DIP-24
E 390951-01IC 74F646A
F 391163-01IC TTL 74LS646 DIP PKG
G 391374-01IC SM 74FCT646A1000+SO-24
H 391374-02IC SM 74FCT646T, LOW SWITCH NOISEA3400, A-4000SO-24

OccurrenceNumberTypePosition Comment
A3000 9 C U253,U254,U255,U256,U703,U704,U705,U706,U707,-
A3000-T 9 C U253,U254,U255,U256,U703,U704,U705,U706,U707,-
A4000 3 H U702, U703, U706,-
A2620 2 D (F?) U205, U206,Differences in images and schematics
A2630 2 D (F?) (C?) U701, U702,Differences in images and schematics

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Last modified: 2017/10/23 01:54