ON Semiconductor MC74AC138, MC74ACT138 Technical data

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MC74AC138, MC74ACT138

1−of−8 Decoder/Demultiplexer

The MC74AC138/74ACT138 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 MC74AC138/74ACT138 devices or a 1−of−32 decoder using four MC74AC138/74ACT138 devices and one inverter.

• Demultiplexing Capability

• Multiple Input Enable for Easy Expansion

• Active LOW Mutually Exclusive Outputs

• Outputs Source/Sink 24 mA

• ′ACT138 Has TTL Compatible Inputs

w These devices are available in Pb−free package(s). Specifications herein

apply to both standard and Pb−free devices. Please see our website at www.onsemi.com for specific Pb−free orderable part numbers, or contact your local ON Semiconductor sales office or representative.

V

O0O1O2O3O4O5O

CC

1516 14 13 12 11 10

6

9

16

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1

16

1

16

1

DIP−16 N SUFFIX CASE 648

SO−16

D SUFFIX

CASE 751B

TSSOP−16 DT SUFFIX

CASE 948F

21 34567

3

8

O

GNDA0A1A2E1E2E

7

Figure 1. Pinout: 16−Lead Packages Conductors

(Top View)

A0A1A

2

O1O2O3O4O5O6O

O

0

E1E2E

3

7

Figure 2. Logic Symbol

PIN ASSIGNMENT

PIN FUNCTION

A0−A

E1−E

E

3

O0−O

2

7

Address Inputs

Enable Inputs

Enable Input

Outputs

EIAJ−16

16

1

M SUFFIX CASE 966

ORDERING INFORMATION

Device Package Shipping

MC74AC138N

MC74ACT138N

MC74AC138D

MC74ACT138D

MC74AC138DR2 2500 Tape & Reel

MC74ACT138DR2 2500 Tape & Reel

MC74AC138DT

MC74ACT138DT

MC74AC138DTR2

MC74ACT138DTR2

MC74AC138M

MC74ACT138M

MC74AC138MEL

MC74ACT138MEL

PDIP−16

SOIC−16

TSSOP−16

EIAJ−16

25 Units/Rail

48 Units/Rail

96 Units/Rail

2500 Tape & Reel

50 Units/Rail

2000 Tape & Reel

DEVICE MARKING INFORMATION

See general marking information in the device marking section on page 6 of this data sheet.

March, 2006 − Rev. 6

1 Publication Order Number:

MC74AC138/D

MC74AC138, MC74ACT138

FUNCTIONAL DESCRIPTION

The MC74AC138/74ACT138 high−speed 1−of−8 decoder/demultiplexer accepts three binary weighted inputs (A

, A1, A2) and, when enabled, provides eight mutually

0

exclusive active−LOW outputs (O

0−O7

). The MC74AC138/74ACT138 features three Enable inputs, two active−LOW (E outputs will be HIGH unless E

, E2) and one active−HIGH (E3). All

1

and E2 are LOW and E3 is

1

TRUTH TABLE

Inputs Outputs

E1E

H X X X X X H H H H H H H H X H X X X X H H H H H H H H X X L X X X H H H H H H H H

L L H L L L L H H H H H H H L L H H L L H L H H H H H H L L H L H L H H L H H H H H L L H H H L H H H L H H H H

L L H L L H H H H H L H H H L L H H L H H H H H H L H H L L H L H H H H H H H H L H L L H H H H H H H H H H H L

H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial

E

A

2

3

0

A2O0O1O2O3O

1

HIGH. This multiple enabled function allows easy parallel expansion of the device to a 1−of−32 (5 lines to 32 lines) decoder with just four MC74AC138/74ACT138 devices and one inverter (See Figure 4). The MC74AC138/74ACT138 can be used as an 8−output demultiplexer by using one of the active LOW Enable inputs as the data input and the other Enable inputs as strobes. The Enable inputs which are not used must be permanently tied to their appropriate active−HIGH or active−LOW state.

O5O6O

4

7

E

E1E

3

A2A

0

7

NOTE: This diagram is provided only for the understanding of logic

operations and should not be used to estimate propagation delays.

A

1

0

6

0

5

4

2

0

3

0

2

0

1

0

Figure 3. Logic Diagram

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MC74AC138, MC74ACT138

A

0

A

1

A

2

′04

A

3

A

4

A0A1A

2

H

123 123 123 123

E

A0A1A

2

E

A0A1A

2

E

A0A1A

2

E

0

001020304050607

0

001020304050607

0

001020304050607

0

001020304050607

0

31

Figure 4. Expansion to 1−of−32 Decoding

MAXIMUM RATINGS*

Symbol Parameter Value Unit

V

I

IN

I

OUT

I

CC

T

CC

IN

OUT

stg

DC Supply Voltage (Referenced to GND) −0.5 to +7.0 V

DC Input Voltage (Referenced to GND) −0.5 to VCC +0.5 V

DC Output Voltage (Referenced to GND) −0.5 to VCC +0.5 V

DC Input Current, per Pin ±20 mA

DC Output Sink/Source Current, per Pin ±50 mA

DC VCC or GND Current per Output Pin ±50 mA

Storage Temperature −65 to +150 °C

*Maximum Ratings are those values beyond which damage to the device may occur. Functional operation should be restricted to the Recom-

mended Operating Conditions.

RECOMMENDED OPERATING CONDITIONS

Symbol Parameter Min Typ Max Unit

V

CC

VIN, V

tr, t

f

tr, t

f

T

J

T

A

I

OH

I

OL

Supply Voltage

DC Input Voltage, Output Voltage (Ref. to GND) 0 − V

OUT

Input Rise and Fall Time (Note 1) ′AC Devices except Schmitt Inputs

Input Rise and Fall Time (Note 2) ′ACT Devices except Schmitt Inputs

Junction Temperature (PDIP) − − 140 °C

Operating Ambient Temperature Range −40 25 85 °C

Output Current − High − − −24 mA

Output Current − Low − − 24 mA

1. VIN from 30% to 70% VCC; see individual Data Sheets for devices that differ from the typical input rise and fall times. from 0.8 V to 2.0 V; see individual Data Sheets for devices that differ from the typical input rise and fall times.

2. V

IN

′AC 2.0 5.0 6.0

′ACT 4.5 5.0 5.5

CC

V

VCC @ 3.0 V − 150 −

VCC @ 4.5 V − 40 − ns/V

VCC @ 5.5 V − 25 −

VCC @ 4.5 V − 10 −

VCC @ 5.5 V − 8.0 −

ns/V

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MC74AC138, MC74ACT138

DC CHARACTERISTICS

V

CC

Symbol Parameter

V

IH

Minimum High Level Input Voltage

(V)

3.0 1.5 2.1 2.1 V

4.5 2.25 3.15 3.15 V or VCC − 0.1 V

5.5 2.75 3.85 3.85

V

IL

Maximum Low Level Input Voltage

3.0 1.5 0.9 0.9 V

4.5 2.25 1.35 1.35 V or VCC − 0.1 V

5.5 2.75 1.65 1.65

V

OH

Minimum High Level Output Voltage

3.0 2.99 2.9 2.9 I

4.5 4.49 4.4 4.4 V

5.5 5.49 5.4 5.4

3.0 − 2.56 2.46 −12 mA

4.5 − 3.86 3.76 I

5.5 − 4.86 4.76 −24 mA

V

OL

Maximum Low Level Output Voltage

3.0 0.002 0.1 0.1 I

4.5 0.001 0.1 0.1 V

5.5 0.001 0.1 0.1

3.0 − 0.36 0.44 12 mA

4.5 − 0.36 0.44 I

5.5 − 0.36 0.44 24 mA

I

IN

I

OLD

I

OHD

I

CC

Maximum Input Leakage Current

†Minimum Dynamic

Output Current

Maximum Quiescent Supply Current

5.5 − ±0.1 ±1.0 μA VI = VCC, GND

5.5 − − 75 mA V

5.5 − − −75 mA V

5.5 − 8.0 80 μA VIN = VCC or GND

*All outputs loaded; thresholds on input associated with output under test. †Maximum test duration 2.0 ms, one output loaded at a time.

NOTE: I

and ICC @ 3.0 V are guaranteed to be less than or equal to the respective limit @ 5.5 V VCC.

IN

TA = +25°C

Typ Guaranteed Limits

74AC 74AC

TA =

−40°C to +85°C

Unit Conditions

= 0.1 V

OUT

= 0.1 V

OUT

= −50 μA

OUT

*VIN = VIL or V

V

OH

OUT

−24 mA

= 50 μA

*VIN = VIL or V

V

OL

OLD

OHD

24 mA

= 1.65 V Max

= 3.85 V Min

IH

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