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TL/F/6413

54LS245/DM54LS245/DM74LS245 TRI-STATE Octal Bus Transceiver

June 1989

54LS245/DM54LS245/DM74LS245

TRI-STATEÉ Octal Bus Transceiver

General Description

These octal bus transceivers are designed for asynchronous

two-way communication between data buses. The

control function implementation minimizes external timing

requirements.

The device allows data transmission from the A bus to the B

bus or from the B bus to the A bus depending upon the logic

level at the direction control (DIR) input. The enable input

(G) can be used to disable the device so that the buses are

effectively isolated.

Features

Y Bi-Directional bus transceiver in a high-density 20-pin

package

Y TRI-STATE outputs drive bus lines directly

Y PNP inputs reduce DC loading on bus lines

Y Hysteresis at bus inputs improve noise margins

Y Typical propagation delay times, port-to-port 8 ns

Y Typical enable/disable times 17 ns

Y IOL (sink current)

54LS 12 mA

74LS 24 mA

Y IOH (source current)

54LS b12 mA

74LS b15 mA

Y Alternate Military/Aerospace device (54LS245) is available.

Contact a National Semiconductor Sales Office/

Distributor for specifications.

Connection Diagram

Dual-In-Line Package

TL/F/6413±1

Order Number 54LS245DMQB, 54LS245FMQB, 54LS245LMQB,

DM54LS245J, DM54LS245W, DM74LS245WM or DM74LS245N

See NS Package Number E20A, J20A, M20B, N20A or W20A

Function Table

Enable

Direction

Operation

G

Control

DIR

L L B data to A bus

L H A data to B bus

H X Isolation

H e High Level, L e Low Level, X e Irrelevant

TRI-STATEÉ is a registered trademark of National Semiconductor Corporation.

C1995 National Semiconductor Corporation RRD-B30M105/Printed in U. S. A.

Absolute Maximum Ratings (Note)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales

Office/Distributors for availability and specifications.

Supply Voltage 7V

Input Voltage

DIR or G 7V

A or B 5.5V

Operating Free Air Temperature Range

DM54LS and 54LS b55§C to a125§C

DM74LS 0§C to a70§C

Storage Temperature Range b65§C to a150§C

Note: The ``Absolute Maximum Ratings'' are those values

beyond which the safety of the device cannot be guaranteed.

The device should not be operated at these limits. The

parametric values defined in the ``Electrical Characteristics''

table are not guaranteed at the absolute maximum ratings.

The ``Recommended Operating Conditions'' table will define

the conditions for actual device operation.

Recommended Operating Conditions

Symbol Parameter

DM54LS245 DM74LS245

Units

Min Nom Max Min Nom Max

VCC Supply Voltage 4.5 5 5.5 4.75 5 5.25 V

VIH High Level Input Voltage 2 2 V

VIL Low Level Input Voltage 0.7 0.8 V

IOH High Level Output Current b12 b15 mA

IOL Low Level Output Current 12 24 mA

TA Free Air Operating Temperature b55 125 0 70 §C

Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)

Symbol Parameter Conditions Min

Typ

Max Units

(Note 1)

VI Input Clamp Voltage VCC e Min, IIe b18 mA b1.5 V

HYS Hysteresis (VTa b VTb) VCC e Min 0.2 0.4 V

VOH High Level Output Voltage VCC e Min, VIH e Min DM74

2.7

VIL e Max, IOHe b1 mA

VCC e Min, VIL e Min DM54/DM74

2.4 3.4 V

VIL e Max, IOHe b3 mA

VCC e Min, VIH e Min DM54/DM74

2

VIL e 0.5V, IOH e Max

VOL Low Level Output Voltage VCC e Min IOL e 12 mA DM74 0.4

VIL e Max

IOL e Max DM54 0.4 V

VIH e Min

DM74 0.5

IOZH Off-State Output Current, VCC e Max VO e 2.7V

20 mA

High Level Voltage Applied VIL e Max

IOZL Off-State Output Current,

VIH e Min

VO e 0.4V

b200 mA

Low Level Voltage Applied

II Input Current at Maximum VCC e Max A or B VI e 5.5V 0.1

mA

Input Voltage

DIR or G VI e 7V 0.1

IIH High Level Input Current VCC e Max, VI e 2.7V 20 mA

IIL Low Level Input Current VCC e Max, VI e 0.4V b0.2 mA

IOS Short Circuit Output Current VCC e Max (Note 2) b40 b225 mA

ICC Supply Current Outputs High VCC e Max 48 70

Outputs Low 62 90 mA

Outputs at Hi-Z 64 95

Note 1: All typicals are at VCC e 5V, TA e 25§C.

Note 2: Not more than one output should be shorted at a time, not to exceed one second duration

2

Switching Characteristics VCC e 5V, TA e 25§C (See Section 1 for Test Waveforms and Output Load)

DM54/74

Symbol Parameter Conditions LS245 Units

Min Max

tPLH Propagation Delay Time, Low-to-High-Level Output 12 ns

tPHL Propagation Delay Time, High-to-Low-Level Output CL e 45 pF 12 ns

tPZL Output Enable Time to Low Level

RL e 667X 40 ns

tPZH Output Enable Time to High Level 40 ns

tPLZ Output Disable Time from Low Level CL e 5 pF 25 ns

tPHZ Output Disable Time from High Level

RL e 667X 25 ns

tPLH Propagation Delay Time, Low-to-High-Level Output 16 ns

tPHL Propagation Delay Time, High-to-Low-Level Output CL e 150 pF 17 ns

tPZL Output Enable Time to Low Level

RL e 667X 45 ns

tPZH Output Enable Time to High Level 45 ns

3

Physical Dimensions inches (millimeters)

Ceramic Leadless Chip Carrier Package (E)

Order Number 54LS245LMQB

NS Package Number E20A

20-Lead Ceramic Dual-In-Line Package (J)

Order Number 54LS245DMQB or DM54LS245J

NS Package Number J20A

4

Physical Dimensions inches (millimeters) (Continued)

20-Lead Small Outline Molded Package (M)

Order Number DM74LS245WM

NS Package Number M20B

20-Lead Molded Dual-In-Line Package (N)

Order Number DM74LS245N

NS Package Number N20A

5

54LS245/DM54LS245/DM74LS245 TRI-STATE Octal Bus Transceiver

Physical Dimensions inches (millimeters) (Continued)

20-Lead Ceramic Flat Package (W)

Order Number 54LS245FMQB or DM54LS245W

NS Package Number W20A

LIFE SUPPORT POLICY

NATIONAL'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT

DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL

SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or 2. A critical component is any component of a life

systems which, (a) are intended for surgical implant support device or system whose failure to perform can

into the body, or (b) support or sustain life, and whose be reasonably expected to cause the failure of the life

failure to perform, when properly used in accordance support device or system, or to affect its safety or

with instructions for use provided in the labeling, can effectiveness.

be reasonably expected to result in a significant injury

to the user.

National Semiconductor National Semiconductor National Semiconductor National Semiconductor

Corporation Europe Hong Kong Ltd. Japan Ltd.

1111 West Bardin Road Fax: (a49) 0-180-530 85 86 13th Floor, Straight Block, Tel: 81-043-299-2309

Arlington, TX 76017 Email: [email protected] Ocean Centre, 5 Canton Rd. Fax: 81-043-299-2408

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Italiano Tel: (a49) 0-180-534 16 80 Fax: (852) 2736-9960

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.

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