DM74AS874 Dual 4-Bit D-Type Edge-Triggered Flip-Flop
October 1986
Revised March 2000
DM74AS874
Dual 4-Bit D-Type Edge-Triggered Flip-Flop
General Description
These dual 4-bit inverting registers feature totem-pole 3-
STATE outputs designed specifically for driving highly-
capacitive or relatively low-impedance loads. The high-
impedance state and increased high-logic-level drive pro-
vide these registers with the capability of being connected
directly to and driving the bus lines in a bus-organized sys-
tem without need for interface or pull-up components. They
are particularly attractive for implementing buffer registers,
I/O ports, bidirectional bus drivers, and working registers.
The eight flip-flops of the DM74AS874 are edge-triggered
D-type flip-flops. On the positive transition of the clock, the
Q outputs will be set to the logic states that were set up at
the D inputs.
A buffered output control input can be used to place the
eight outputs in either a normal logic state (HIGH or LOW
logic levels) or a high-impedance state. In the high-imped-
ance state the outputs neither load nor drive the bus lines
significantly.
The output control does not affect the internal operation of
the flip-flops. That is, the old data can be retained or new
data can be entered even while the outputs are OFF.
The pinout is arranged to ease printed circuit board layout.
All data inputs are on one side of the package, while all
outputs are on the other side.
Features
s
Switching specifications at 50 pF
s
Switching specifications guaranteed over full tempera-
ture and V
CC
range
s
Advanced oxide-isolated, ion-implanted Schottky TTL
process
s
3-STATE buffer-type outputs drive bus lines directly
s
Space saving 300 mil wide package
s
Bus structured pinout
Ordering Code:
Order Number
DM74AS874WM
DM74AS874NT
Package Number
M24B
N24C
Package Description
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
Devices also available in Tape and Reel. Specify by appending the suffix letter 鈥淴鈥?to the ordering code.
Connection Diagram
漏 2000 Fairchild Semiconductor Corporation
DS006331
www.fairchildsemi.com
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