D-Type Flip-Flops in a Single Package With
3-State Bus Driving True Outputs
D
Full Parallel Access for Loading
D
Buffered Control Inputs
D
Package Options Include Plastic
Small-Outline (DW) Packages, Ceramic
Chip Carriers (FK), and Standard Plastic (N)
and Ceramic (J) DIPs
description
These octal D-type edge-triggered 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.
On the positive transition of the clock (CLK) input,
the Q outputs are set to the logic levels set up at
the data (D) inputs.
A buffered output-enable (OE
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 the increased drive
provide the capability to drive bus lines without
interface or pullup components.
) input places the
SN54ALS374A, SN54AS374 . . . J PACKAGE
SN74ALS374A, SN74AS374 . . . DW OR N PACKAGE
SN54ALS374A, SN54AS374 . . . FK PACKAGE
2D
2Q
3Q
3D
4D
(TOP VIEW)
OE
1
1Q
2
1D
3
2D
4
2Q
5
3Q
6
3D
7
4D
8
9
4Q
GND
10
(TOP VIEW)
1D1QOE
3212019
4
5
6
7
8
910111213
4Q
GND
20
19
18
17
16
15
14
13
12
11
CLK
CC
V
5Q
V
8Q
8D
7D
7Q
6Q
6D
5D
5Q
CLK
18
17
16
15
14
5D8Q
CC
8D
7D
7Q
6Q
6D
OE
does not affect 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 SN54ALS374A and SN54AS374 are characterized for operation over the full military temperature range
of –55°C to 125°C. The SN74ALS374A and SN74AS374 are characterized for operation from 0°C to 70°C.
FUNCTION TABLE
(each flip-flop)
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.
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.
INPUTS
OECLKD
L↑HH
L↑LL
LH or LXQ
HXXZ
OUTPUT
Q
0
Copyright 1999, Texas Instruments Incorporated
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.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
1
SN54ALS374A, SN54AS374, SN74ALS374A, SN74AS374
UNIT
OCTAL D-TYPE EDGE-TRIGGERED FLIP-FLOPS
WITH 3-STATE OUTPUTS
SDAS167C – APRIL 1982 – REVISED NOVEMBER 1999
logic symbol
1
OE
11
CLK
3
1D
4
2D
7
3D
8
4D
13
5D
14
6D
17
7D
18
8D
†
This symbol is in accordance with ANSI/IEEE Std 91-1984 and
IEC Publication 617-12.
†
EN
C1
12
15
16
19
2
1Q
5
2Q
6
3Q
9
4Q
5Q
6Q
7Q
8Q
1D
logic diagram (positive logic)
1
OE
11
CLK
C1
1D
1D
3
To Seven Other Channels
2
1Q
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTE 1: The package thermal impedance is calculated in accordance with JESD 51.
B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.
C. When measuring propagation delay items of 3-state outputs, switch S1 is open.
D. All input pulses have the following characteristics: PRR ≤ 1 MHz, tr = tf = 2 ns, duty cycle = 50%.
E. The outputs are measured one at a time with one transition per measurement.
VOLTAGE WAVEFORMS
Test
Point
500 Ω
1.3 V
t
h
1.3 V1.3 V
1.3 V1.3 V
1.3 V
1.3 V
VOL + 0.3 V
500 Ω
From Output
Under Test
CL = 50 pF
(see Note A)
LOAD CIRCUIT FOR
OPEN-COLLECTOR OUTPUTS
3.5 V
0.3 V
3.5 V
0.3 V
3.5 V
0.3 V
t
PLZ
≈3.5 V
V
OL
t
PHZ
V
VOH – 0.3 V
OH
≈0 V
Out-of-Phase
Test
Point
High-Level
Pulse
Low-Level
Pulse
Input
In-Phase
Output
Output
(see Note C)
From Output
Under Test
CL = 50 pF
(see Note A)
LOAD CIRCUIT FOR
3-STATE OUTPUTS
1.3 V1.3 V
t
w
1.3 V1.3 V
VOLTAGE WAVEFORMS
PULSE DURATIONS
1.3 V1.3 V
t
PLH
1.3 V1.3 V
t
PHL
1.3 V1.3 V
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
500 Ω
500 Ω
3.5 V
0.3 V
3.5 V
0.3 V
t
PHL
t
PLH
Test
Point
3.5 V
0.3 V
V
OH
V
OL
V
OH
V
OL
Figure 3. Load Circuits and Voltage Waveforms
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
IMPORTANT NOTICE
T exas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty . Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
CERTAIN APPLICA TIONS USING SEMICONDUCT OR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICA TIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERST OOD TO
BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright 1999, Texas Instruments Incorporated
Loading...
+ hidden pages
You need points to download manuals.
1 point = 1 manual.
You can buy points or you can get point for every manual you upload.