DM74AS257_07 Datasheet, PDF (1/8 Pages) Fairchild Semiconductor – 3-STATE Quad 1 of 2 Line Data Selector/Multiplexers

May 2007
DM74AS257, DM74AS258
tm
3-STATE Quad 1 of 2 Line Data Selector/Multiplexers
Features
■ Switching specifications at 50pF
■ Switching specifications guaranteed over full
temperature and V_CC range
■ Advanced oxide-isolated, ion-implanted Schottky
TTL process
■ Functionally and pin for pin compatible with Schottky,
low power Schottky, and advanced low power
Schottky TTL counterpart
■ Improved AC performance over Schottky, low power
Schottky, and advanced low power Schottky
counterparts
■ 3-STATE buffer-type output drive bus lines directly
■ Expand any data input point
■ Multiplex dual data buses
■ General four functions of two variables (one variable
is common)
■ Source programmable counters
General Description
These data selectors/multiplexers contain inverters and
drivers to supply full on-chip data selection to the four
3-STATE outputs that can interface directly with data
lines of bus-organized systems. A 4-bit word selected
from one of two sources is routed to the four outputs.
The DM74AS257 presents true data whereas the
DM74AS258 presents inverted data to minimize propa-
gation delay time.
This 3-STATE output feature means that n-bit (paral-
leled) data selectors with up to 300 sources can be
implemented for data buses. It also permits the use of
standard TTL registers for data retention throughout the
system.
Ordering Information
Order
Number
Package
Number
Package Description
DM74AS257M
DM74AS257N
DM74AS258M
M16A
N16E
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering number.
©1986 Fairchild Semiconductor Corporation
DM74AS257, DM74AS258 Rev. 1.2
www.fairchildsemi.com