Fairchild Semiconductor DM74AS244WMX, DM74AS244WM, DM74AS244SJX, DM74AS244N Datasheet

© 2000 Fairchild Semiconductor Corporation DS006298 www.fairchildsemi.com

October 1986
Revised March 2000

DM74AS240 • DM74AS244 3-STATE Bus Driver/Receiver

DM74AS240 • DM74AS244
3-STATE Bus Driver/Receiver

General Description

This family of Advance Sc hottky 3-STATE Bus circuits are
designed to provide either bidirectional or unidirectional
buffer interface in Memory, Microprocessor, and Communi­cation Systems. The out put characteristics of the circui ts
have low impedance suffi cient to drive terminated trans­mission lines down to 133Ω. The input characteristics of
the circuits likewise have a high impedance s o it will not
significantly load the transmission line. The package con­tains eight 3-STATE buffers organized with four buffers
having a common 3-STATE enable gate. The DM74AS240
and DM74AS244 are eight w ide in a 20 pin package, and
may be used as a 4 wide bid irectional or eight wide un idi­rectional. The buffer sel ection includes invert ing and non­inverting, with enable or disable 3-STATE control.

Features

■ Advanced oxide-isolated, ion-implanted Schottky TTL
process

■ Improved switching per formance with less power dissi­pation compared with Schottky counterpart

■ Functional and pin compa tible with 74LS and Schottky
counterpart

■ Switching response specified into 500Ω and 50 pF

■ Specified to interface with CMOS at V

OH

= VCC − 2V

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 Diagrams

DM74AS240 DM74AS244

Function Tables

DM74AS240 DM74AS244

L = LOW Logic Level H = HIGH Logic Level X = Either LOW or HIGH Lo gic Level Z = High Imp edance

Order Number Package Number Package Description

DM74AS240WM M20B 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
DM74AS240N N20A 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
DM74AS244WM M20B 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
DM74AS244N N20A 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide

Inputs Output

G

AY

LL H
LH L

HX Z

Inputs Output

G

AY

LL L
LH H

HX Z

www.fairchildsemi.com 2

DM74AS240 • DM74AS244

Absolute Maximum Ratings(Note 1)

Note 1: The “Absolute Maximum Ratin gs” are those v alues beyon d 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. All typical values are measured at VCC = 5V, TA = 25°C.

Note 2: The output c onditions have been ch os en to produce a current that closely approximat es one half the true shor t- c irc uit output current, IOS.

Supply Voltage, V

CC

7V
Input Voltage 7V
Voltage Applied to Disabled Output 5.5V
Operating Free Air Temperature Range 0°C to +70°C
Storage Temper ature Range −65°C to +150°C
Typical θ

JA

N Package 57.0°C/W
M Package 76.0°C/W

Symbol Parameter Min Nom Max Units

V

CC

Supply Voltage 4.5 5 5.5 V

V

IH

HIGH Level Input Voltage 2 V

V

IL

LOW Level Input Voltage 0.8 V

I

OH

HIGH Level Output Current −15 mA

I

OL

LOW Level Output Current 64 mA

T

A

Free Air Operating Temperature 0 70 °C

Symbol Parameter Conditions Min Typ Max Units

V

IK

Input Clamp Voltage VCC = 4.5V, IIN = −18 mA −1.2 V

V

OH

HIGH Level VCC = 4.5V, IOH = −3 mA 2.4 3.2

VOutput Voltage VCC = 4.5V, IOH = Max 2.4

IOH = −2 mA, VCC = 4.5V to 5.5V VCC−2

V

OL

LOW Level Output Voltage VCC = 4.5V, IOL = Max 0.35 0.55 V

I

I

Input Current at Max Input Voltage VCC = 5.5V VIN = 7V Others 100 µA

I

IH

HIGH Level Input Current VCC = 5.5V, VIN = 2.7V Others 20 µA

I

IL

LOW Level Input Current VCC = 5.5V, VIN = 0.4V AS240, (G, G),

µA

(Control Inputs), −500
DM74AS244 (G)
DM74AS244 (A) −1000

I

OZH

HIGH Level 3-STATE Output Current VCC = 5.5V, V= 2.7V 50 µA

I

OZL

LOW Level 3-STATE

VCC = 5.5V, V = 0.4V

DM74AS240,

−50 µA

Output Current DM74AS244

IO (Note 2) Output Drive Current VCC = 5.5V, V

OUT

= 2.25V −50 −115 −150 mA

I

CC

DM74AS240 VCC = 5.5V Outputs HIGH 11 17
Supply Current Outputs LOW 51 75 mA

3-STATE 24 38

I

CC

DM74AS244 VCC = 5.5V Outputs HIGH 22 34
Supply Current Outputs LOW 60 90 mA

3-STATE 34 54