SN54HC374, SN74HC374
OCTAL EDGE-TRIGGERED D-TYPE FLIP-FLOPS
WITH 3-STATE OUTPUTS
SCLS141C – DECEMBER 1982 – REVISED JUL Y 1998
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
D
Eight D-Type Flip-Flops in a Single Package
D
High-Current 3-State True Outputs Can
Drive up to 15 LSTTL Loads
D
Full Parallel Access for Loading
D
Package Options Include Plastic Shrink
Small-Outline (DB), Small-Outline (DW),
Thin Shrink Small-Outline (PW), and
Ceramic Flat (W) Packages, Ceramic Chip
Carriers (FK), and Standard Plastic (N) and
Ceramic (J) DIPs
description
These 8-bit flip-flops feature 3-state outputs
designed specifically for driving highly capacitive
or relatively low-impedance loads. They are
particularly suitable for implementing buffer
registers, I/O ports, bidirectional bus drivers, and
working registers.
The eight flip-flops of the ’HC374 devices are
edge-triggered D-type flip-flops. On the positive
transition of the clock (CLK) input, the Q outputs
are set to the logic levels that were set up at the
data (D) inputs.
An output-enable (OE
) input places the eight
outputs in either a normal logic state (high or low
logic levels) or the high-impedance state. In the
high-impedance state, the outputs neither load
nor drive the bus lines significantly . The high-impedance state and increased drive provide the capability to drive
bus lines without interface or pullup components.
OE
does not affect the internal operations of the flip-flops. Old data can be retained or new data can be entered
while the outputs are in the high-impedance state.
T o ensure the high-impedance state during power up or power down, OE
should be tied to VCC through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
The SN54HC374 is characterized for operation over the full military temperature range of –55°C to 125°C.
The SN74HC374 is characterized for operation from –40°C to 85°C.
FUNCTION TABLE
(each flip-flop)
INPUTS
OUTPUT
OE CLK D
Q
L ↑ H H
L ↑ LL
LH or L X Q
0
H X X Z
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
3212019
910111213
4
5
6
7
8
18
17
16
15
14
8D
7D
7Q
6Q
6D
2D
2Q
3Q
3D
4D
1D1QOE
5Q
5D
V
8Q
4Q
GND
CLK
SN54HC374 . . . FK PACKAGE
(TOP VIEW)
CC
SN54HC374 ...J OR W PACKAGE
SN74HC374 . . . DB, DW, N, OR PW PACKAGE
(TOP VIEW)
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
OE
1Q
1D
2D
2Q
3Q
3D
4D
4Q
GND
V
CC
8Q
8D
7D
7Q
6Q
6D
5D
5Q
CLK
Copyright 1998, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
On products compliant to MIL-PRF-38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.