Typical Propagation Delay Times Port to
Port, 8 ns
I
OL
TYPE
SN54LS24512 mA–12 mA
SN74LS24524 mA–15 mA
(SINK
CURRENT)
I
OH
(SOURCE
CURRENT)
description
These octal bus transceivers are designed for
asynchronous two-way communication between
data buses. The control-function implementation
minimizes external timing requirements.
The devices allow data transmission from the
A bus to the B bus or from the B bus to the A bus,
depending on the logic level at the
direction-control (DIR) input. The output-enable
(OE
) input can disable the device so that the
buses are effectively isolated.
SN54LS245 ...J OR W PACKAGE
SN74LS245 ... DB, DW, N, OR NS PACKAGE
SN54LS245 . . . FK P ACKAGE
A3
A4
A5
A6
A7
(TOP VIEW)
1
DIR
2
A1
3
A2
4
A3
5
A4
6
A5
7
A6
8
A7
9
A8
GND
10
(TOP VIEW)
A2A1DIR
3 2 1 20 19
4
5
6
7
8
910111213
A8
B8
20
19
18
17
16
15
14
13
12
11
V
B7
CC
V
OE
B1
B2
B3
B4
B5
B6
B7
B8
OE
18
17
16
15
14
B6
CC
B1
B2
B3
B4
B5
GND
T
A
PDIP – NTubeSN74LS245NSN74LS245N
0°C to 70°C
SOP – NSTape and reelSN74LS245NSR74LS245
SSOP – DBT ape and reelSN74LS245DBRLS245
°
–
†
Package drawings, standard packing quantities, thermal data, symbolization, and PCB design
guidelines are available at www.ti.com/sc/package.
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.
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
SN54LS245, SN74LS245
OPERATION
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SDLS146A – OCTOBER 1976 – REVISED FEBRUARY 2002
schematics of inputs and outputs
FUNCTION TABLE
INPUTS
OEDIR
LLB data to A bus
LHA data to B bus
HXIsolation
EQUIVALENT OF EACH INPUT
V
CC
9 kΩ NOM
Input
logic diagram (positive logic)
DIR
TYPICAL OF ALL OUTPUTS
V
CC
50 Ω NOM
Output
1
19
OE
2
2
A1
To Seven Other Channels
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
18
B1
UNIT
SN54LS245, SN74LS245
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SDLS146A – OCTOBER 1976 – REVISED FEBRUARY 2002
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V
Input voltage, V
Package thermal impedance,
Storage temperature range, T
†
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. All voltage values are with respect to GND.
2. The package thermal impedance is calculated in accordance with JESD 51-7.
switching characteristics, VCC = 5 V, TA = 25°C (see Figure 1)
PARAMETERTEST CONDITIONSMINTYPMAX
t
PLH
PHL
t
PZL
t
PZH
t
PLZ
t
PHZ
Propagation delay time, low- to high-level output
p
Output enable time to low level
Output enable time to high level
Output disable time from low level
Output disable time from high level
p
,
=
L
p
,
=
L
p
,
=
L
UNIT
=
L
=
L
=
L
812
2740
2540
1525
1528
ns
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
From Output
Under Test
(see Note A)
Test
Point
C
L
SDLS146A – OCTOBER 1976 – REVISED FEBRUARY 2002
PARAMETER MEASUREMENT INFORMATION
SERIES 54LS/74LS DEVICES
V
CC
V
CC
R
L
R
(see Note B)
From Output
Under Test
(see Note A)
C
L
L
Test
Point
SN54LS245, SN74LS245
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
V
CC
From Output
Under Test
(see Note A)
Test
R
Point
C
L
L
S1
(see Note B)
5 kΩ
S2
FOR 2-STATE TOTEM-POLE OUTPUTS
High-Level
Low-Level
In-Phase
(see Note D)
Out-of-Phase
(see Note D)
NOTES: A. CL includes probe and jig capacitance.
LOAD CIRCUIT
Pulse
Pulse
Input
t
PLH
Output
t
PHL
Output
PROPAGATION DELAY TIMES
B. All diodes are 1N3064 or equivalent.
C. 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.
D. S1 and S2 are closed for t
E. Phase relationships between inputs and outputs have been chosen arbitrarily for these examples.
F. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, ZO ≈ 50 Ω, tr ≤ 1.5 ns, tf ≤ 2.6 ns.
G. The outputs are measured one at a time with one input transition per measurement.
1.3 V1.3 V
t
w
1.3 V1.3 V
VOLTAGE WAVEFORMS
PULSE DURATIONS
1.3 V1.3 V
1.3 V1.3 V
1.3 V1.3 V
VOLTAGE WAVEFORMS
, t
PLH
PHL
t
PHL
t
PLH
, t
FOR OPEN-COLLECTOR OUTPUTS
PHZ
LOAD CIRCUIT
3 V
0 V
V
OH
V
OL
V
OH
V
OL
, and t
PLZ
Timing
Input
Data
Input
Output
Control
(low-level
enabling)
t
PZL
Waveform 1
(see Notes C
and D)
t
PZH
Waveform 2
(see Notes C
and D)
ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS
; S1 is open and S2 is closed for t
LOAD CIRCUIT
FOR 3-STATE OUTPUTS
1.3 V
t
su
1.3 V1.3 V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
1.3 V1.3 V
1.3 V
1.3 V
VOLTAGE WAVEFORMS
; S1 is closed and S2 is open for t
PZH
3 V
0 V
t
h
3 V
0 V
3 V
0 V
t
PLZ
≈1.5 V
VOL + 0.5 V
V
OL
t
PHZ
V
OH
VOH – 0.5 V
≈1.5 V
.
PZL
Figure 1. Load Circuits and Voltage Waveforms
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
5
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications,
enhancements, improvements, and other changes to its products and services at any time and to discontinue
any product or service without notice. Customers should obtain the latest relevant information before placing
orders and should verify that such information is current and complete. All products are sold subject to TI’s terms
and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty . Testing and other quality control techniques are used to the extent TI
deems necessary to support this warranty . Except where mandated by government requirements, testing of all
parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for
their products and applications using TI components. T o minimize the risks associated with customer products
and applications, customers should provide adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right,
copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process
in which TI products or services are used. Information published by TI regarding third–party products or services
does not constitute a license from TI to use such products or services or a warranty or endorsement thereof.
Use of such information may require a license from a third party under the patents or other intellectual property
of the third party , or a license from TI under the patents or other intellectual property of TI.
Reproduction of information in TI data books or data sheets is permissible only if reproduction is without
alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction
of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for
such altered documentation.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that
product or service voids all express and any implied warranties for the associated TI product or service and
is an unfair and deceptive business practice. TI is not responsible or liable for any such statements.
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2002, 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.