SN74LS181N3 Texas Instruments Integrated Circuit (Dual-In-Line Packages) In Stock
SN74LS181N3 is a 4-bit arithmetic logic unit (ALU) and function generator in a 24-PDIP package, operating from 5 V supply with up to 70°C ambient temperature. It supports 16 arithmetic and 16 logic operations, with internal carry lookahead for high-speed operation. Suitable for CPU data-path, digital signal processing, and bus-oriented computing systems.
- Manufacturer
- Texas Instruments
- Package
- Dual-In-Line Packages
- Pin Count
- 24
- Lifecycle
- OBSOLETE
- Datasheet
- SN74LS181N3 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 SN74LS181N3?
- 4-bit ALU supporting 16 arithmetic and 16 logic operations
- Internal carry lookahead for accelerated 5 V TTL-level arithmetic
- Active-HIGH and active-LOW operand inputs for flexible logic design
- 24-PDIP through-hole package rated 0°C to 70°C
- Cascadable architecture with carry generate/propagate outputs
- LS-family TTL with 15 pF load capacitance specification
What is SN74LS181N3 used for?
The SN74LS181N3 is used in legacy CPU arithmetic data-paths and microprocessor system designs where 4-bit parallel arithmetic operations are required. It fits digital computer architecture prototypes, educational computing platforms, and industrial control logic that require multi-function bitwise and arithmetic operations. Its cascadable carry outputs also make it suitable for building wide-word ALU stages in retro-computing and FPGA emulation verification boards.
What are the specifications of SN74LS181N3?
| Pbfree Code | No |
| YTEOL | 0 |
| Additional Feature | CAPABLE OF 16 LOGIC & ARITHMETIC OPERATIONS; INTERNAL CARRY AND HIGHER ORDER LOOKAHEAD |
| Family | LS |
| JESD-30 Code | R-PDIP-T24 |
| Load Capacitance (CL) | 15pF |
| Logic IC Type | ARITHMETIC LOGIC UNIT |
| Number of Bits | 4 |
| Number of Functions | 1 |
| Output Polarity | TRUE |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | DIP24,.6 |
| Package Shape | RECTANGULAR |
| Package Style | IN-LINE |
| Peak Reflow Temperature (Cel) | NOT SPECIFIED |
| Power Supply Current-Max (ICC) | 220mA |
| Propagation Delay (tpd) | 62ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 5.25V |
| Supply Voltage-Min (Vsup) | 4.75V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | NO |
| Technology | TTL |
| Temperature Grade | COMMERCIAL |
| Terminal Form | THROUGH-HOLE |
| Terminal Pitch | 2.54mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | NOT SPECIFIED |
| 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 SN74LS181N3 datasheet?
SN74LS181N3 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN74LS181N3?
Compatible alternatives and drop-in replacements for SN74LS181N3:
Frequently Asked Questions
How many arithmetic and logic operations does the SN74LS181N3 support?
The SN74LS181N3 supports 16 distinct arithmetic operations and 16 distinct logic operations, totalling 32 selectable functions on its 4-bit data paths. This versatility makes it valuable in CPU data-path design, operating from a 5 V TTL supply with load capacitance specified at 15 pF.
What is the operating temperature range and supply voltage for SN74LS181N3?
The SN74LS181N3 is rated for a commercial temperature range of 0°C to 70°C and operates from a 5 V TTL supply rail. Its 24-PDIP package is suited for through-hole PCB assembly in benchtop computing and prototype logic systems requiring stable operation within this thermal window.
Can SN74LS181N3 units be cascaded to handle wider data words than 4 bits?
Yes, the SN74LS181N3 provides carry generate and carry propagate outputs that allow multiple devices to be cascaded for 8-bit, 16-bit, or wider ALU structures. The internal lookahead carry logic reduces propagation delay when chaining multiple 4-bit slices, enabling higher-speed arithmetic at 5 V TTL logic levels across cascaded stages.
Which PCB form factor does SN74LS181N3 use and how does this affect board layout?
The SN74LS181N3 uses a 24-pin PDIP (Dual In-Line Package) with 2.54 mm through-hole pitch, requiring approximately 30 mm of board length. This package suits prototyping and breadboard work, with the 24 pins providing direct access to all 4-bit operand inputs, function-select lines, carry input, and output signals.
In which legacy computing architectures is SN74LS181N3 commonly used as an alternative to a custom ALU?
The SN74LS181N3 was widely adopted in minicomputer and early microprocessor designs of the 1970s–1980s, including bit-slice CPU boards operating at 5 V with clock speeds below 10 MHz. It remains a go-to component for retro-computing restoration projects, TTL-based educational CPU kits, and logic-design coursework that requires a discrete 4-bit ALU with full 32-function capability.
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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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