SN74ALS521NE4 Texas Instruments Integrated Circuit (Dual-In-Line Packages) In Stock
SN74ALS521NE4 is an 8-bit identity comparator from Texas Instruments in the ALS logic family, housed in a 20-pin DIP package, with cascadable architecture and built-in pull-up resistors on Q inputs for comparing two 8-bit words in digital address decoding and data validation circuits.
- Manufacturer
- Texas Instruments
- Package
- Dual-In-Line Packages
- Pin Count
- 20
- Lifecycle
- OBSOLETE
- Datasheet
- SN74ALS521NE4 Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- ?°C to 70.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SN74ALS521NE4?
- 8-bit identity comparator for parallel word comparison
- Cascadable design for expanding to 16-bit or wider comparison
- Built-in pull-up resistors on Q inputs simplify external wiring
- ALS family with 50 pF load capacitance for fast propagation
- 20-pin DIP package for breadboard prototyping and through-hole assembly
- RoHS compliant (JESD-609 e4) and Pb-free
What is SN74ALS521NE4 used for?
SN74ALS521NE4 is used in digital systems requiring fast 8-bit word equality detection, such as address comparators in memory map decoders, bus arbiters, and hardware security modules that check data integrity. Multiple devices can be cascaded to compare 16-bit or 32-bit words by chaining the cascade-enable outputs. It also serves as a magnitude comparator in industrial control logic, programmable logic replacement boards, and legacy digital system maintenance applications.
What are the specifications of SN74ALS521NE4?
| Pbfree Code | Yes |
| YTEOL | 0 |
| Additional Feature | WITH PULL-UP RESISTORS ON Q INPUTS; CASCADABLE |
| Family | ALS |
| JESD-30 Code | R-PDIP-T20 |
| JESD-609 Code | e4 |
| Load Capacitance (CL) | 50pF |
| Logic IC Type | IDENTITY COMPARATOR |
| Number of Bits | 8 |
| Number of Functions | 1 |
| Output Characteristics | 3-STATE |
| Output Polarity | INVERTED |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | DIP20,.3 |
| Package Shape | RECTANGULAR |
| Package Style | IN-LINE |
| Packing Method | TUBE |
| Power Supply Current-Max (ICC) | 19mA |
| Propagation Delay (tpd) | 20ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 5.5V |
| Supply Voltage-Min (Vsup) | 4.5V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | NO |
| Technology | TTL |
| Temperature Grade | COMMERCIAL |
| Terminal Finish | NICKEL PALLADIUM GOLD |
| Terminal Form | THROUGH-HOLE |
| Terminal Pitch | 2.54mm |
| Terminal Position | DUAL |
| ## SN74ALS521NE4 Alternates Showing results | Image |
| Package | Dual-In-Line Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| HTS Code | 8542.39.00.60 |
Where can I find the SN74ALS521NE4 datasheet?
SN74ALS521NE4 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN74ALS521NE4?
Compatible alternatives and drop-in replacements for SN74ALS521NE4:
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Frequently Asked Questions
How does SN74ALS521NE4 perform 8-bit identity comparison, and can it be expanded?
SN74ALS521NE4 compares two 8-bit input words A and B and asserts an active-low output when all 8 bit pairs are equal. It includes a cascade input that allows multiple devices to be chained together for 16-bit, 24-bit, or wider comparisons without external glue logic, with propagation delay typically in the low nanosecond range at 50 pF load.
What role do the built-in pull-up resistors on Q inputs play in SN74ALS521NE4 circuit design?
The integrated pull-up resistors on the Q inputs of SN74ALS521NE4 ensure that undriven or open inputs default to a logic-high state, preventing spurious comparison results from floating lines. This eliminates the need for external resistor networks, reducing component count and PCB area in address decoding and bus comparison applications.
Where is SN74ALS521NE4 typically deployed in digital system design?
SN74ALS521NE4 is most commonly used in memory address decoders where a CPU or DMA controller output must match a fixed 8-bit base address to select a peripheral, as well as in data validation circuits that confirm byte-level integrity across parallel buses. Legacy industrial controllers, FPGA replacement boards, and embedded system prototypes also use it for fast hardware equality checks at 50 pF load capacitance.
Is SN74ALS521NE4 compatible with RoHS requirements for modern production builds?
Yes, SN74ALS521NE4 carries a JESD-609 code of e4 and a Pb-free designation, confirming it meets RoHS 2 directives restricting hazardous substances including lead in electronic assemblies. The NE4 suffix in the part number denotes the RoHS-compliant, lead-free version, making it suitable for products shipped into the EU, Japan, and other markets with strict environmental regulations.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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