March 1988
Revised August 1999
74F646 • 74F646B • 74F648
Octal Transceiver/Register with 3-STATE Outputs
General Description
Features
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 pro-
vided 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
■ 74F648 has inverting data paths
■ 74F646/74F646B have non-inverting data paths
■ 74F646B is a faster version of the 74F646
■ 3-STATE outputs
■ 300 mil slim DIP
Ordering Code:
Order Number Package Number
Package Description
74F646SC
M24B
MSA24
N24C
M24B
N24C
M24B
N24C
24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
24-Lead Shrink Small Outline Package (SSOP), EIAJ TYPE II, 5.3mm Wide
24-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-100, 0.300 Wide
24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
24-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-100, 0.300 Wide
24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
24-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-100, 0.300 Wide
74F646MSA
74F646SPC
74F646BSC
74F646BSPC
74F648SC
74F648SPC
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
© 1999 Fairchild Semiconductor Corporation
DS009580
www.fairchildsemi.com