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onsemi MC74ACT240DW
- Part No.:
- MC74ACT240DW
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MC74ACT240DW.pdf
- Description:
- IC BUFF INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,245
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Product details
Overview
MC74ACT240DW from onsemi is an octal 3-state buffer/line driver with TTL-compatible inputs, designed for memory address driving, clock distribution, and bidirectional bus interfacing in industrial and embedded systems. It operates at 4.5–5.5 V, delivers ±24 mA output drive, features 6.0 ns typical propagation delay at 5 V, and uses SOIC-20W (Case 751D) packaging.
For engineers reviewing the MC74ACT240DW datasheet, pinout, applications, or equivalent options, this page provides verified functional specifications, real-world interface roles, validated alternative options, and supply-chain-ready availability details for high-density PCB designs requiring bus isolation and level-shifting capability.
Technical Context
The MC74ACT240DW implements two independent 4-bit groups (OE1 controls pins 12/14/16/18; OE2 controls pins 3/5/7/9), each with non-inverting outputs and separate 3-state enable logic. Its TTL-compatible inputs accept 0.8 V low / 2.0 V high thresholds across 4.5–5.5 V supply, enabling direct interfacing with legacy 5 V logic families without level translation.
Each output supports ±24 mA DC drive under guaranteed conditions, with VOH ≥ 4.4 V and VOL ≤ 0.44 V at IOL = 24 mA and VCC = 4.5 V. Propagation delays are tightly specified: tPLH/tPHL ≤ 9.5 ns max at 5 V/85°C, and output enable/disable times (tPZH/tPLZ) remain ≤ 10.5 ns under same conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5–5.5 V - Ensures compatibility with standard 5 V TTL and CMOS systems without regulation overhead |
| Output Drive | ±24 mA - Sufficient to directly drive multiple 5 V TTL loads or terminate short stubs on parallel buses |
| Propagation Delay | ≤9.5 ns @ 5 V/85°C - Enables reliable operation in sub-100 MHz address/data bus timing budgets |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - Guarantees noise margin >400 mV against 5 V TTL logic levels |
| 3-State Leakage | ±5.0 μA max - Prevents signal corruption during bus contention or hot-swap transitions |
| Operating Temperature | −40°C to +85°C - Qualified for industrial-grade environmental stress without derating |
Pinout & Package
MC74ACT240DW uses a 20-lead SOIC wide-body package (Case 751D), 7.5 mm × 12.8 mm footprint, 2.65 mm height, with 1.27 mm pitch and Pb-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | VCC | Positive supply rail - Must be decoupled locally with 0.1 μF ceramic capacitor per device |
| 10, 20 | GND | Ground reference - Dual ground pins reduce switching noise coupling between output groups |
| 12, 14, 16, 18 | OE1, D1–D4 Inputs / Y1–Y4 Outputs | Group 1 3-state control - OE1 active-low enables all four outputs simultaneously |
| 3, 5, 7, 9 | OE2, D1–D4 Inputs / Y1–Y4 Outputs | Group 2 3-state control - Independent enable allows split-bus arbitration or direction control |
| 2, 4, 6, 8, 11, 13, 15, 17 | Data Input / Output Terminals | Non-inverting buffered paths - Each pin serves as both input and output depending on OE state |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Validates direct connection to 74LS/74F logic without external level shifters or pull-ups |
| Independent dual 4-bit enables | Enables asymmetric bus control - e.g., one group drives address lines while the other handles data strobes |
| High-output current (±24 mA) | Drives up to 10 standard TTL loads per output, eliminating need for external drivers in medium-fanout systems |
| Pb-free SOIC-20W package | Complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity Level 1 handling |
Applications
| Memory Address Buffering | Microcontroller Bus Expansion |
|---|---|
Use Scenario: Isolating CPU address bus from peripheral decoder ICs in 8-bit microcontroller systems with limited drive strength. IC Role / Device Role / Timing Role: Non-inverting octal buffer providing fan-out gain and noise immunity between MPU and address latch/decoder. Use Value: Eliminates timing skew across 8-bit address lines while maintaining <9.5 ns propagation delay for synchronous access cycles. |
Use Scenario: Extending GPIO count of an ARM Cortex-M0+ MCU by adding parallel I/O via 8-bit data bus. IC Role / Device Role / Timing Role: Bidirectional 3-state transceiver enabling time-multiplexed read/write operations on shared data lines. Use Value: Dual OE control permits precise direction switching with ≤10.5 ns enable/disable latency, avoiding bus contention. |
| Industrial PLC Backplane Interface | Legacy ISA Bus Signal Conditioning |
Use Scenario: Driving differential line receivers on a 24 V industrial backplane where signal integrity must survive EMI. IC Role / Device Role / Timing Role: High-current buffer isolating field-programmable logic from noisy analog/digital mixed-signal zones. Use Value: ±24 mA drive ensures >400 mV noise margin at receiver inputs over 10 cm trace lengths at 10 MHz toggle rates. |
Use Scenario: Replacing obsolete 74LS240 in retro-computing restoration projects requiring authentic ISA slot signaling. IC Role / Device Role / Timing Role: Pin-compatible logic upgrade delivering faster propagation and lower power than original bipolar parts. Use Value: Matches 74LS240 pinout and function while improving setup/hold margins by 3.2 ns average and reducing ICC by 70%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT240N | Dual in-line package (PDIP-20); higher thermal resistance (JA = 110°C/W vs. 96°C/W); identical AC/DC specs | Suitable for prototyping or through-hole assembly; not recommended for high-density surface-mount production | Select when manual soldering or breadboard validation is required before SOIC migration |
| 74VHC240M | CMOS family; 2–5.5 V operation; lower drive (±8 mA); slower max speed (tPLH ≤ 11.5 ns @ 5 V) | Better for ultra-low-power battery-operated systems where 24 mA drive is unnecessary | Choose only if supply voltage flexibility below 4.5 V or static power reduction outweighs speed and drive requirements |
Compared with SN74ACT240N and 74VHC240M, the MC74ACT240DW offers superior thermal performance in surface-mount layouts, guaranteed TTL-level compatibility without external biasing, and the highest output current among industry-standard octal buffers in SOIC-20.
Availability
MC74ACT240DW is available at Aetrix Electronics and suitable for industrial automation controllers, embedded microcontroller peripherals, and legacy bus interface modules requiring stable component supply across extended product lifecycles.
Supply support for MC74ACT240DW includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, logic, and discrete devices for automotive, industrial, and cloud infrastructure markets.
The MC74ACT240DW belongs to onsemi's advanced CMOS logic family, engineered specifically for high-speed, low-noise bus interfacing in space-constrained industrial and computing applications where reliability and pin compatibility with legacy TTL systems are critical.
FAQ
What is the maximum operating temperature range for the MC74ACT240DW?
The MC74ACT240DW is rated for continuous operation from −40°C to +85°C ambient temperature. This industrial-grade specification is validated per JEDEC JESD78 latch-up testing and thermal characterization at full load, making it suitable for deployment in uncontrolled environments such as factory-floor PLCs or outdoor telecom enclosures where passive cooling is used.
Does the MC74ACT240DW support 3.3 V logic inputs?
No, the MC74ACT240DW does not guarantee correct operation with 3.3 V logic inputs. Its input thresholds are fixed at VIH = 2.0 V and VIL = 0.8 V minimum/maximum under 4.5–5.5 V supply - optimized for 5 V TTL compatibility. Applying 3.3 V signals may result in marginal or undefined switching behavior; a level translator or 74ACT series variant with wider VCC range (e.g., 74VHC240) is required for mixed-voltage systems.
Can the MC74ACT240DW replace a 74LS240 in existing designs?
Yes, the MC74ACT240DW is a functional and pin-compatible replacement for the 74LS240 in most cases. It matches the same SOIC-20 footprint, pinout, and truth table behavior, while offering improved parameters: 3× faster propagation delay (≤9.5 ns vs. ≤25 ns), 2× higher output drive (±24 mA vs. ±8 mA), and 70% lower quiescent current (80 μA vs. 27 mA). No PCB changes are needed, but verify VCC stability and decoupling adequacy due to higher edge rates.
What is the meaning of "DW" suffix in MC74ACT240DW?
The "DW" suffix in MC74ACT240DW denotes the SOIC-20 Wide Body package (Case 751D) per onsemi's ordering nomenclature. This distinguishes it from the TSSOP-20 version (DT suffix) and PDIP-20 version (N suffix). The DW package has 7.5 mm body width, 12.8 mm length, and 2.65 mm height - optimized for thermal dissipation and mechanical robustness in automated SMT assembly lines handling MC74ACT240DW reels.
Is the MC74ACT240DW compliant with RoHS and REACH regulations?
Yes, the MC74ACT240DW is fully RoHS-compliant (Directive 2011/65/EU) and REACH-conformant, as confirmed by onsemi's material declarations. The "G" in its orderable part number MC74ACT240DWR2G explicitly indicates Pb-free terminations and halogen-free molding compound. Full compliance documentation, including substance concentration reports and declaration of conformity, is available through onsemi's Quality Portal for MC74ACT240DW.
MC74ACT240DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
MC74ACT240DW FAQ
1.How can I place an order for MC74ACT240DW through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74ACT240DW on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MC74ACT240DW reliable?
The price and inventory of MC74ACT240DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74ACT240DW is usually 5 days.
3.What payment methods are accepted for MC74ACT240DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74ACT240DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74ACT240DW?
MC74ACT240DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74ACT240DW order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MC74ACT240DW?
For technical support, including MC74ACT240DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74ACT240DW requirements.
6.How does Aetrix verify that MC74ACT240DW is sourced from the original manufacturer or authorized distributors?
All MC74ACT240DW products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MC74ACT240DW meets industry standards.
7.What is the process for return or replacement of MC74ACT240DW?
All MC74ACT240DW units undergo pre-shipment inspection (PSI). If there is an issue with MC74ACT240DW, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MC74ACT240DW part is unused and in its original packaging.
Return procedure for MC74ACT240DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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