HD74LS240P Texas Instruments Integrated Circuit (Dual-In-Line Packages) In Stock
HD74LS240P is an octal inverting 3-state buffer/line driver from Texas Instruments in a 20-pin DIP package. It features two 4-bit enable inputs and 3-state outputs for bus-driving at TTL logic levels. Available from stock with worldwide shipping.
- Manufacturer
- Texas Instruments
- Package
- Dual-In-Line Packages
- Pin Count
- 20
- Lifecycle
- ACTIVE
- Datasheet
- HD74LS240P Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $2.1368(MOQ 1)
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- Octal 3-state inverting outputs drive 8 data lines simultaneously, ideal for bus expansion circuits
- Two independent 4-bit output-enable controls allow flexible multiplexing of 74LS logic buses
- TTL-compatible 5 V operation with 24 mA sink current supports direct backplane bus driving
Applications
HD74LS240P is widely used as a bus driver and address demultiplexer in legacy 5 V TTL digital systems, including memory interfaces, microprocessor data buses, and industrial controller backplanes. Its inverted 3-state outputs make it suitable for driving long PCB traces where signal reflection must be minimized with matched termination. The 20-pin DIP format simplifies prototyping and through-hole board assembly in retrofit or repair projects.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Alternate & Equivalent Parts
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How many output channels does the HD74LS240P provide, and what is the maximum sink current per output?
HD74LS240P provides 8 inverting 3-state output channels organized as two 4-bit groups. Each output can sink up to 24 mA in the LOW state, making it capable of driving TTL and LSTTL loads directly on a 5 V bus without external buffers.
How does the dual output-enable structure of HD74LS240P simplify bidirectional bus designs?
HD74LS240P has two separate active-LOW output-enable pins, each controlling a 4-bit group of outputs. This lets a designer independently enable or tri-state each nibble, so a 74LS240 and a 74LS244 can share the same 8-bit bus with minimal glue logic, reducing component count by at least 1 extra gate IC.
In what legacy system scenarios is the 20-pin DIP package of HD74LS240P still the preferred choice over SOIC variants?
The 20-pin DIP package is preferred for through-hole prototyping boards, ZIF-socket test fixtures, and field repair of older industrial PLCs or S-100 bus systems. DIP parts can be inserted and removed without soldering, saving significant rework time when debugging address decode logic running at 5 V TTL levels.
What propagation delay and supply voltage does the HD74LS240P require, and how does that compare to AHCT240 alternatives?
HD74LS240P operates from a 5 V supply with a typical propagation delay of approximately 9 ns. The AHCT240 alternative operates from 4.5 V to 5.5 V and achieves roughly 5 ns propagation delay, so AHCT240 is faster, but HD74LS240P fits directly in existing 74LS footprints without redesign when timing margins exceed 9 ns.
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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.
| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 1+ | $3.4650 | $3.46 |
| 31+ | $2.3100 | $71.61 |
| 109+ | $2.1368 | $232.91 |
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