September 1986
Revised April 2000
DM74ALS520 • DM74ALS521
8-Bit Comparator
General Description
These comparators perform an “equal to” comparison of two 8-bit words with provision for expansion or external enabling. The matching of the two 8-bit input plus a logic LOW on the EN input produces the output A = B on the DM74ALS520 and DM74ALS521. The DM74ALS520 and DM74ALS521 have totem pole outputs for wire AND cascading. Additionally, the DM74ALS520 is provided with B input pull up termination resistors for analog or switch data.
Features
■Switching specifications at 50 pF
■Switching specifications guaranteed over full temperature and VCC range
■Advanced oxide-isolated, ion-implanted Schottky TTL process
■Functionally and pin for pin compatible with LS family counterpart
■Improved output transient handling capability
Ordering Code:
Ordering Code |
Package Number |
Package Description |
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DM74ALS520WM |
M20B |
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide |
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DM74ALS520N |
N20A |
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide |
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DM74ALS521WM |
M20B |
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide |
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SM74ALS521N |
N20A |
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide |
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Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram |
Function Table |
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Inputs |
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Output |
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EN |
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Data |
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A |
= |
B |
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L |
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A = |
B |
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L |
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L |
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A ≠ |
B |
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H |
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H |
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X |
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H |
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H = HIGH Logic Level |
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L = LOW Logic Level |
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X = Don't Care |
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Comparator Bit-8 DM74ALS521 • DM74ALS520
© 2000 Fairchild Semiconductor Corporation |
DS006114 |
www.fairchildsemi.com |
DM74ALS520 • DM74ALS521
Logic Diagram
www.fairchildsemi.com |
2 |
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