3-State Noninverting Outputs Drive Bus
Lines Directly
D
Full Parallel Access for Loading
D
EPIC
t
(Enhanced-Performance Implanted
CMOS) 1-µm Process
D
Package Options Include Plastic
Small-Outline (DW) Shrink Small-Outline
(DB), and Thin Shrink Small-Outline (PW)
Packages, Ceramic Chip Carriers (FK) and
Flatpacks (W), and Standard Plastic (N) and
Ceramic (J) DIPs
description
SN54AC374 ...J OR W PACKAGE
SN74AC374 . . . DB, DW, N, OR PW PACKAGE
OE
1Q
1D
2D
2Q
3Q
3D
4D
4Q
GND
(TOP VIEW)
20
1
19
2
18
3
17
4
16
5
15
6
14
7
13
8
12
9
11
10
V
CC
8Q
8D
7D
7Q
6Q
6D
5D
5Q
CLK
These 8-bit flip-flops feature 3-state outputs
designed specifically for driving highly capacitive
or relatively low-impedance loads. The devices
are particularly suitable for implementing buffer
registers, I/O ports, bidirectional bus drivers, and
working registers.
The eight flip-flops of the ’AC374 are D-type
edge-triggered flip-flops. 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
) input can be used
to place the eight outputs in either a normal
logic state (high or low logic levels) or the high-
SN54AC374 . . . FK PACKAGE
2D
2Q
3Q
3D
4D
(TOP VIEW)
1D1QOE
3 2 1 20 19
4
5
6
7
8
9 10 11 12 13
4Q
CLK
GND
V
CC
5Q
8Q
18
17
16
15
14
5D
8D
7D
7Q
6Q
6D
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 in bus-organized systems
without need for interface or pullup components.
OE
does not affect internal operations of the flip-flop. Old data can be retained or new data can be entered while
the outputs are in the high-impedance state.
The SN54AC374 is characterized for operation over the full military temperature range of –55°C to 125°C. The
SN74AC374 is characterized for operation from –40°C to 85°C.
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.
EPIC is a trademark of 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.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
FUNCTION TABLE
(each flip-flop)
INPUTS
OECLKD
L↑HH
L↑LL
LH or LXQ
HXXZ
OUTPUT
Q
0
Copyright 1996, Texas Instruments Incorporated
1
SN54AC374, SN74AC374
OCTAL D-TYPE EDGE-TRIGGERED FLIP-FLOPS
WITH 3-STATE OUTPUTS
SCAS543B – OCTOBER 1995 - REVISED JUNE 1996
1
11
3
4
7
8
13
14
17
18
†
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
‡
logic symbol
OE
CLK
1D
2D
3D
4D
5D
6D
7D
8D
†
This symbol is in accordance with ANSI/IEEE Std 91-1984
and IEC Publication 617-12.
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.
NOTES: 1. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
2. The maximum package power dissipation is calculated using a junction temperature of 150°C and a board trace length of 750 mils,
except for the N package, which has a trace length of zero.
Power dissipation capacitanceCL = 50 pF, f = 1 MHz40pF
pd
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
From Output
Under Test
CL = 50 pF
(see Note A)
Input
50% V
500 Ω
LOAD CIRCUIT
t
w
CC
VOLTAGE WAVEFORMS
OCTAL D-TYPE EDGE-TRIGGERED FLIP-FLOPS
SCAS543B – OCTOBER 1995 - REVISED JUNE 1996
PARAMETER MEASUREMENT INFORMATION
2 × V
500 Ω
S1
50% V
CC
3 V
0 V
CC
Open
Timing Input
Data Input
TESTS1
t
PLH/tPHL
t
PLZ/tPZL
t
PHZ/tPZH
t
su
50% V
VOLTAGE WAVEFORMS
SN54AC374, SN74AC374
WITH 3-STATE OUTPUTS
Open
2 × V
CC
Open
V
0 V
V
0 V
CC
CC
50% V
CC
CC
50% V
t
h
CC
Input
t
PLH
In-Phase
Output
t
PHL
Out-of-Phase
Output
NOTES: A. CL includes probe and jig capacitance.
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. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, ZO = 50 Ω, tr ≤ 2.5 ns, tf ≤ 2.5 ns.
D. The outputs are measured one at a time with one input transition per measurement.
50% V
CC
50% V
50% V
VOLTAGE WAVEFORMS
50% V
CC
CC
Figure 1. Load Circuit and Voltage Waveforms
CC
t
PHL
50% V
t
PLH
50% V
CC
CC
V
0 V
V
V
V
V
CC
OH
OL
OH
OL
Output
Control
(low-level
enabling)
Output
Waveform 1
S1 at 2 × V
(see Note B)
Output
Waveform 2
S1 at Open
(see Note B)
CC
t
PZL
t
PZH
CC
CC
50% V
VOL + 0.3 V
VOH – 0.3 V
50% V
CC
t
PLZ
50% V
t
PHZ
50% V
VOLTAGE WAVEFORMS
CC
V
0 V
[
V
V
[
CC
V
OL
OH
0 V
CC
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
5
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 1998, Texas Instruments Incorporated
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