Datasheet DM74LS245WMX, DM74LS245WM, DM74LS245SJX, DM74LS245SJ, DM74LS245N Datasheet (Fairchild Semiconductor)

© 2000 Fairchild Semiconductor Corporation DS006413 www.fairchildsemi.com

August 1986
Revised March 2000

DM74LS245 3-STATE Octal Bus Transceiver

DM74LS245
3-STATE Octal Bus Transceiver

General Description

These octal bus transceivers ar e designed for asynchro­nous two-way communication between data buses. The
control function im plementation minimizes exte rnal timing
requirements.

The device allows data t ransmiss ion fr om the A Bus to t he
B Bus or from the B Bus to th e A Bus depe ndin g upo n the
logic level at the direction control (DIR) input. The enable
input (G

) can be used to disa ble the device so that the

buses are effectively isolated.

Features

■ Bi-Directional bus tr ansceiver in a high-density 20-pin
package

■ 3-STATE outputs drive bus lines directly

■ PNP inputs reduce DC loading on bus lines

■ Hysteresis at bus inputs improve noise margins

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

■ Typical enable/disable times 17 ns

■ I

OL

(sink current)

24 mA

■ I

OH

(source current)

−15 mA

Ordering Code:

Devices also availab le in Tape and Reel. Specify by appending th e s uffix let t er “X” to the ordering code.

Connection Diagram Function Table

H = HIGH Level
L = LOW Level
X = Irrelevant

Order Number Package Number Package Description

DM74LS245WM M20B 20-Lead Small Outline Integrated Circuit (SOIC), JED EC MS-013, 0.300 Wide
DM74LS245SJ M20D 20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
DM74LS245N N20A 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide

Enable Direction Operation

G

Control

DIR

L L B Data to A Bus
L H A Data to B Bus

HX Isolation

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DM74LS245

Absolute Maximum Ratings(Note 1)

Note 1: The “Absolute Maximum Ratings” are those values beyond which

the safety of the dev ice cannot be guaranteed. T he device sh ould not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommend ed O peratin g Cond itions” t able w ill defin e the co ndition s
for actual device operation.

Recommended Operating Conditions

Electrical Characteristics

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

Note 2: All typicals are at VCC = 5V, TA = 25°C.
Note 3: Not more than one output should be shorted at a time, not to exceed one second duration

Supply Voltage 7V
Input Voltage

DIR or G

7V

A or B 5.5V
Operating Free Air Temperature Range 0°C to +70°C
Storage Temperature Range −65°C to +150°C

Symbol Parameter Min Nom Max Units

V

CC

Supply Voltage 4.75 5 5.25 V

V

IH

HIGH Level Input Voltage 2 V

V

IL

LOW Level Input Volt age 0.8 V

I

OH

HIGH Level Output Current −15 mA

I

OL

LOW Level Output Current 24 mA

T

A

Free Air Operating Temperature 0 70 °C

Symbol Parameter Conditions Min

Typ

Max Units

(Note 2)

V

I

Input Clamp Voltage VCC = Min, II = −18 mA −1.5 V

HYS Hysteresis (VT+ − VT−)V

CC

= Min 0.2 0.4 V

V

OH

HIGH Level VCC = Min, VIH = Min

2.7

Output Voltage VIL = Max, IOH = −1 mA

VCC = Min, VIL = Min

2.4 3.4 V

VIL = Max, IOH = −3 mA
VCC = Min, VIH = Min

2

VIL = 0.5V, IOH = Max

V

OL

LOW Level VCC = Min IOL = 12 mA 0.4
Output Voltage VIL = Max

IOL = Max 0.5

V

VIH = Min

I

OZH

Off-State Output Current, VCC = Max

VO = 2.7V 20 µA

HIGH Level Voltage Applied VIL = Max

I

OZL

Off-State Output Current, VIH = Min

VO = 0.4V −200 µA

LOW Level Voltage Applied

I

I

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

mA

Input Voltage DIR or G VI = 7V 0.1

I

IH

HIGH Level Input Current VCC = Max, VI = 2.7V 20 µA

I

IL

LOW Level Input Current VCC = Max, VI = 0.4V −0.2 mA

I

OS

Short Circuit Output Current VCC = Max (Note 3) −40 −225 mA

I

CC

Supply Current Outputs HIGH

VCC = Max

48 70
Outputs LOW 62 90 mA
Outputs at Hi-Z 64 95

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DM74LS245

Switching Characteristics

VCC = 5V, TA = 25°C

Symbol Parameter Conditions Min Max Units

t

PLH

Propagation Delay Time, CL = 45 pF

12 ns

LOW-to-HIGH Level Output RL = 667Ω

t

PHL

Propagation Delay Time,

12 ns

HIGH-to-LOW Level Output

t

PZL

Output Enable Time

40 ns

to LOW Level

t

PZH

Output Enable Time

40 ns

to HIGH Level

t

PLZ

Output Disable Time CL = 5 pF

25 ns

from LOW Level RL = 667Ω

t

PHZ

Output Disable Time

25 ns

from HIGH Level

t

PLH

Propagation Delay Time, CL = 150 pF

16 ns

LOW-to-HIGH Level Output RL = 667Ω

t

PHL

Propagation Delay Time,

17 ns

HIGH-to-LOW Level Output

t

PZL

Output Enable Time

45 ns

to LOW Level

t

PZH

Output Enable Time

45 ns

to HIGH Level

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DM74LS245

Physical Dimensions inches (millimeters) unless otherwise noted

20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide

Package Number M20B

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DM74LS245

Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide

Package Number M20D

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DM74LS245 3-STATE Octal Bus Transceiver

Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide

Package Number N20A

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

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FAIRCHILD’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 FAIRCHILD
SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the
body, or (b) support or sustain life, and (c) whose failure
to perform when properly used in accordance with
instructions for use provided in the labeling, can be rea­sonably expected to result in a significant inju ry to the
user.

2. A critical component in any compon ent of a life supp ort
device or system whose failu re to perform can be rea­sonably expected to ca use the fa i lure of the life su pp ort
device or system, or to affect its safety or effectiveness.

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