MOTOROLA SN74LS138D, SN74LS138DR2, SN74LS138M, SN74LS138MEL, SN74LS138ML1 Datasheet

SN74LS138

1-of-8 Decoder/

Demultiplexer

The LSTTL / MSI SN74LS138 is a high speed 1-of-8 Decoder / Demultiplexer. This device is ideally suited for high speed bipolar memory chip select address decoding. The multiple input enables allow parallel expansion to a 1-of-24 decoder using just three LS138 devices or to a 1-of-32 decoder using four LS138s and one inverter. The LS138 is fabricated with the Schottky barrier diode process for high speed and is completely compatible with all ON Semiconductor TTL families.

•Demultiplexing Capability

•Multiple Input Enable for Easy Expansion

•Typical Power Dissipation of 32 mW

•Active Low Mutually Exclusive Outputs

•Input Clamp Diodes Limit High Speed Termination Effects

GUARANTEED OPERATING RANGES

Symbol	Parameter	Min	Typ	Max	Unit
VCC	Supply Voltage	4.75	5.0	5.25	V
TA	Operating Ambient	0	25	70	°C
	Temperature Range
IOH	Output Current ± High			± 0.4	mA
IOL	Output Current ± Low			8.0	mA

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LOW

POWER

SCHOTTKY

16

1

PLASTIC

N SUFFIX

CASE 648

16

1

SOIC

D SUFFIX

CASE 751B

ORDERING INFORMATION

Device	Package	Shipping
SN74LS138N	16 Pin DIP	2000 Units/Box
SN74LS138D	16 Pin	2500/Tape & Reel

Semiconductor Components Industries, LLC, 1999	1	Publication Order Number:
December, 1999 ± Rev. 6		SN74LS138/D

SN74LS138

CONNECTION DIAGRAM DIP (TOP VIEW)

VCC

O

0

O

1

O

2

O

3

O

4

O

5

O

6

16

15

14

13

12

11

10

9

NOTE:

The Flatpak version has the same

pinouts (Connection Diagram) as

the Dual In-Line Package.

1

2

3

4

5

6

7

8

A0

A1

A2

1

2

E3

7 GND

E

E

O

LOADING (Note a)

PIN NAMES

HIGH

LOW

A0 ± A2

Address Inputs

0.5 U.L.

0.25 U.L.

E

1,

E

2

Enable (Active LOW) Inputs

0.5 U.L.

0.25 U.L.

E3

Enable (Active HIGH) Input

0.5 U.L.

0.25 U.L.

O

0 ±

O

7

Active LOW Outputs

10 U.L.

5 U.L.

NOTES:

a) 1 TTL Unit Load (U.L.) = 40 mA HIGH/1.6 mA LOW.

LOGIC SYMBOL

1		2	3	4 5 6
				1 2 3
A	0 A1 A2			E

O0 O1 O2 O3 O4 O5 O6 O7

15 14 13 12 11 10 9 7

VCC = PIN 16

GND = PIN 8

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2

			SN74LS138
			LOGIC DIAGRAM
A2	A1	A0	E1 E2 E3
3	2	1	4 5	6	VCC = PIN 16
					GND = PIN 8
					= Pin Numbers

7	9	10	11	12	13	14	15
O7		O6	O5	O4 O3	O2	O1	O0

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3