
SN54HCT574, SN74HCT574
OCTAL EDGE-TRIGGERED D-TYPE FLIP-FLOPS
WITH 3-STATE OUTPUTS
SCLS177C – MARCH 1984 – REVISED MAY 1997
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
D
Inputs Are TTL-Voltage Compatible
D
High-Current 3-State Noninverting Outputs
Drive Bus Lines Directly or up to 15 LSTTL
Loads
D
Bus-Structured Pinout
D
Package Options Include Plastic
Small-Outline (DW), Thin Shrink
Small-Outline (PW), and Ceramic Flat (W)
Packages, Ceramic Chip Carriers (FK), and
Standard Plastic (N) and Ceramic (J)
300-mil DIPs
description
These octal edge-triggered D-type flip-flops
feature 3-state outputs designed specifically for
bus driving. They are particularly suitable for
implementing buffer registers, I/O ports,
bidirectional bus drivers, and working registers.
The eight flip-flops enter data on the low-to-high
transition of the clock (CLK) input.
A buffered output-enable (OE) input can be used
to place 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.
The SN54HCT574 is characterized for operation over the full military temperature range of –55°C to 125°C. The
SN74HCT574 is characterized for operation from –40°C to 85°C.
FUNCTION TABLE
(each flip-flop)
INPUTS OUTPUT
OE CLK DQ
L↑H H
L↑LL
LH or L X Q0
H X X Z
Copyright 1997, Texas Instruments Incorporated
UNLESS OTHERWISE NOTED this document contains PRODUCTION
DATA information 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.
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
2Q
3Q
4Q
5Q
6Q
3D
4D
5D
6D
7D
2D
1D
OE
8Q
7Q V
1Q
8D
GND
CLK
SN54HCT574 . . . FK PACKAGE
(TOP VIEW)
CC
SN54HCT574 ...J OR W PACKAGE
SN74HCT574 ...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
1D
2D
3D
4D
5D
6D
7D
8D
GND
VCC
1Q
2Q
3Q
4Q
5Q
6Q
7Q
8Q
CLK