Document
74AC139 • 74ACT139 Dual 1-of-4 Decoder/Demultiplexer
November 1988 Revised November 1999
74AC139 • 74ACT139 Dual 1-of-4 Decoder/Demultiplexer
General Description
The AC/ACT139 is a high-speed, dual 1-of-4 decoder/ demultiplexer. The device has two independent decoders, each accepting two inputs and providing four mutuallyexclusive active-LOW outputs. Each decoder has an active-LOW Enable input which can be used as a data input for a 4-output demultiplexer. Each half of the AC/ ACT139 can be used as a function generator providing all four minterms of two variables.
Features
s ICC reduced by 50% s Multifunction capability s Two completely independent 1-of-4 decoders s Active LOW mutually exclusive outputs s Outputs source/sink 24 mA s ACT139 has TTL-compatible inputs
Ordering Code:
Order Number 74AC139SC 74AC139SJ 74AC139MTC 74AC139PC 74ACT139SC 74ACT139SJ 74ACT139MTC 74ACT139PC Package Number M16A M16D MTC16 N16E M16A M16D MTC16 N16E Package Description 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150” Narrow Body 16-Lead Small Outline Package (SOIC), EIAJ Type II, 5.3mm Wide 16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150” Narrow Body 16-Lead Small Outline Package (SOIC), EIAJ Type II, 5.3mm Wide 16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide
Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.
Connection Diagram
Pin Descriptions
Pin Names A0, A1 E O0–O3 Description Address Inputs Enable Inputs Outputs
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© 1999 Fairchild Semiconductor Corporation
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74AC139 • 74ACT139
Logic Symbols
Functional Description
The AC/ACT139 is a high-speed dual 1-of-4 decoder/ demultiplexer. The device has two independent decoders, each of which accepts two binary weighted inputs (A0–A1) and provides four mutually exclusive active-LOW outputs (O0–O3). Each decoder has an active-LOW enable (E). When E is HIGH all outputs are forced HIGH. The enable can be used as the data input for a 4-output demultiplexer application. Each half of the AC/ACT139 generates all four minterms of two variables. These four minterms are useful in some applications, replacing multiple gate functions as shown in Figure 1, and thereby reducing the number of packages required in a logic network.
IEEE/IEC
FIGURE 1. Gate Functions (Each Half)
Truth Table
Inputs E H L L L L A0 X L H L H A1 X L L H H O0 H L H H H Outputs O1 H H L H H O2 H H H L H O3 H H H H L
Logic Diagram
H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial
Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation .