© 2000 Fairchild Semiconductor Corporation DS009925 www.fairchildsemi.com
November 1988
Revised August 2000
7
4
AC
1
38
• 74ACT138 1-of
-8 Decoder
/
Demult
ip
lexer
74AC138 74ACT138
1-of-8 Decoder/Demultiplexer
General Description
The AC/ACT138 is a high-speed 1-of-8 decoder/demulti-
plexer. 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 AC/ACT138 devices or a 1-of-32 decoder
using four AC/ACT138 devices and one inverter.
Features
a73 I
CC
reduced by 50%
a73 Demultiplexing capability
a73 Multiple input enable for easy expansion
a73 Active LOW mutually exclusive outputs
a73 Outputs source/sink 24 mA
a73 ACT138 has TTL-compatible inputs

Ordering Code:
Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.
Connection Diagram
Pin Descriptions
Logic Symbols
IEEE/IEC
FACT is a trademark of Fairchild Semiconductor Corporation.
Order Number Package Number Package Description
74AC138SC M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
74AC138SJ M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74AC138MTC MTC16 16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
74AC138PC N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
74ACT138SC M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
74ACT138SJ M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74ACT138PC N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Pin Names Description
A
0
–A
2
Address Inputs
E
1
–E
2
Enable Inputs
E
3
Enable Input
O
0
–O
7
Outputs