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onsemi MC74ACT540NG
- Part No.:
- MC74ACT540NG
- Manufacturer:
- onsemi
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
MC74ACT540NG.pdf
- Description:
- IC BUFF INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,405
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Product details
Overview
MC74ACT540NG from onsemi is an octal inverting buffer/line driver with 3-state outputs, designed for memory and address bus interfacing, clock distribution, and bidirectional bus transceivers. It operates at 4.5 V to 5.5 V supply, delivers ±24 mA output drive, features TTL-compatible inputs, and supports flow-through pinout (inputs on one side, outputs on the other) for microprocessor port applications.
For engineers reviewing the MC74ACT540NG datasheet, pinout, applications, or equivalent options, this page provides verified functional identity, SOIC-20W package mapping, truth-table–confirmed 3-state control logic, propagation delay (tPLH/tPHL ≤ 7.5 ns @ 5 V), and validated alternatives for bus buffering in industrial control and embedded systems.
Technical Context
The MC74ACT540NG implements eight independent inverting buffers, each with dual 3-state enable inputs (OE1 and OE2) controlling all outputs simultaneously. Its TTL-compatible input thresholds (VIH = 2.0 V, VIL = 0.8 V @ VCC = 5 V) ensure direct interface with legacy 5 V logic families without level shifting.
It uses a flow-through architecture: inputs occupy pins 1–10 and 20, outputs occupy pins 11–19, enabling straight PCB trace routing between microprocessor data/address buses and peripheral devices. Output disable timing (tPHZ/tPLZ ≤ 12.5 ns) and low dynamic power dissipation (CPD = 30 pF) support high-speed, low-noise bus driving in noise-sensitive environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures compatibility with standard 5 V TTL and CMOS systems without regulation overhead. |
| Output Drive | ±24 mA - Sufficient to drive 15–20 pF loads across 10 cm traces while maintaining signal integrity at >20 MHz. |
| Propagation Delay | tPLH/tPHL ≤ 7.5 ns @ 5 V, CL = 50 pF - Enables reliable operation in 100+ MHz bus cycles with margin. |
| 3-State Enable Time | tPZH/tPZL ≤ 11.5 ns @ 5 V - Supports fast bus turnaround in shared-memory or DMA transfer protocols. |
| Input Compatibility | TTL-compatible VIH/VIL - Directly interfaces with 74LS, 74F, and microcontroller GPIOs without external biasing. |
| Power Dissipation Cap | CPD = 30 pF - Predictable dynamic current draw simplifies thermal design in dense PCB layouts. |
| ESD Rating | HBM > 2000 V - Withstands handling and board-level ESD events per IEC 61000-4-2 Level 2. |
Pinout & Package
MC74ACT540NG is housed in a Pb-free SOIC-20 wide-body package (Case 751D), 12.8 mm × 7.5 mm × 2.65 mm, with 1.27 mm pitch, suitable for reflow soldering and automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | Input A1–A8 | Inverting data inputs; tied directly to microprocessor data/address lines or memory bus drivers. |
| 9, 10 | OE1, OE2 | Active-low 3-state enables; both must be LOW to activate outputs; OR'd internally for flexible control. |
| 11, 12, 13, 14, 15, 16, 17, 18 | Output Y1–Y8 | Inverted buffered outputs; drive bus lines or peripheral inputs with rail-to-rail swing and 24 mA sink/source. |
| 19 | GND | Ground reference for all I/O and internal logic; requires low-inductance connection to system ground plane. |
| 20 | VCC | Positive supply; decoupling capacitor (0.1 µF ceramic) required within 5 mm of this pin for stable switching. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffer | Enables bidirectional bus arbitration by allowing multiple drivers to share one line without contention when disabled. |
| Flow-through pinout | Inputs on left (pins 1–10), outputs on right (pins 11–19) - eliminates layer jumps and reduces crosstalk in high-density layouts. |
| TTL-compatible inputs | VIH = 2.0 V min, VIL = 0.8 V max @ 5 V - ensures robust noise margin and interoperability with legacy 5 V logic families. |
| ±24 mA output drive | Supports fan-out of ≥10 LS-TTL loads or direct interface to 50 Ω transmission lines with controlled edge rates. |
| Pb-free SOIC-20W | RoHS-compliant, JEDEC-standard package with verified thermal resistance (θJA = 96 °C/W) for industrial ambient operation. |
Applications
| Industrial PLC I/O Expansion | Legacy Microprocessor Bus Interface |
|---|---|
|
Use Scenario: Expanding digital I/O capacity in programmable logic controllers using parallel bus backplanes. IC Role / Device Role / Timing Role: Inverting buffer isolating CPU address/data bus from field I/O modules while enabling 3-state bus sharing. Use Value: Prevents bus contention during module hot-swap; ±24 mA drive sustains signal integrity over 30 cm ribbon cables at 10 MHz. |
Use Scenario: Interfacing Z80 or 8086-based embedded controllers with external RAM, ROM, and peripheral ICs. IC Role / Device Role / Timing Role: Address latch driver and data bus transceiver with inverted polarity matching legacy memory decode logic. Use Value: Flow-through pinout aligns with CPU pin layout, reducing PCB layer count; tPLH ≤ 7.5 ns meets 100 ns bus cycle timing budgets. |
| Test Equipment Signal Conditioning | Automated Test Fixture Control |
|
Use Scenario: Driving calibrated logic levels into DUT inputs during functional test of mixed-signal boards. IC Role / Device Role / Timing Role: Precision voltage-level translator and current-boosted buffer ensuring clean transitions under capacitive load. Use Value: VOL ≤ 0.44 V @ 24 mA guarantees valid LOW recognition across temperature; HBM > 2000 V protects against probe-induced ESD. |
Use Scenario: Controlling relay banks, LED indicators, and solenoid drivers in production test fixtures. IC Role / Device Role / Timing Role: High-current digital output expander translating microcontroller GPIO signals into robust actuator control lines. Use Value: Dual OE inputs allow synchronized enable/disable of all eight channels via single FPGA control signal, simplifying fixture firmware. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT540N | Same logic function, pinout, and DC specs; TI version uses different process, resulting in slightly higher ICC (10 µA vs 8 µA typ) and identical AC performance. | Identical use in 5 V bus systems; TI's qualification includes extended temperature screening for military-grade variants not offered by onsemi. | Select SN74ACT540N if sourcing from TI-dedicated supply chains or requiring MIL-PRF-38535 compliance documentation. |
| MC74ACT540DWG | Same die and functionality; DWG suffix denotes same SOIC-20W package but non-green (halogen-containing) molding compound per older RoHS exemption. | No functional difference; used where legacy BOMs specify non-Pb-free variant or where halogen content is not restricted by end-equipment standards. | Choose MC74ACT540DWG only when replacing existing DWG stock or complying with specific customer material declarations excluding "G" suffix. |
Compared with MC74ACT540NG, SN74ACT540N offers equivalent electrical behavior with minor quiescent current variance and broader qualification scope, while MC74ACT540DWG differs solely in halogen content-both serve as drop-in replacements in 5 V logic designs but require attention to environmental compliance and supply chain alignment.
Availability
MC74ACT540NG is available at Aetrix Electronics and suitable for industrial PLCs, legacy microprocessor systems, automated test equipment, and embedded control applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MC74ACT540NG 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 focused on energy-efficient innovation for automotive, industrial, cloud, medical, and IoT applications.
The MC74ACT540NG belongs to onsemi's legacy 74ACT logic family, engineered for high-speed, low-power 5 V TTL-compatible interfacing in industrial and embedded systems where reliability and long-term availability are critical.
FAQ
What is the operating voltage range for MC74ACT540NG?
The MC74ACT540NG operates over a supply voltage range of 4.5 V to 5.5 V. This narrow window ensures TTL-compatible input thresholds and stable 3-state output behavior. Operation outside this range may cause undefined logic states or excessive ICC; it is not rated for 3.3 V or 6 V operation. The MC74ACT540NG datasheet specifies guaranteed performance only within these limits.
Does MC74ACT540NG support true bidirectional bus operation?
No, MC74ACT540NG is an inverting unidirectional buffer. It drives data from inputs (A1–A8) to outputs (Y1–Y8) only. Bidirectional bus control requires pairing with a complementary device like MC74ACT541NG or using external direction logic. The MC74ACT540NG truth table confirms outputs are always inverted and never reflect Y→A feedback.
What is the meaning of the "G" suffix in MC74ACT540NG?
The "G" suffix in MC74ACT540NG indicates a Pb-free (lead-free) package compliant with RoHS Directive 2011/65/EU. It uses matte tin lead finish and halogen-free molding compound. This differs from MC74ACT540DWG (non-G), which contains lead in the finish and halogens in the epoxy. The MC74ACT540NG is the environmentally preferred version for new designs.
Can MC74ACT540NG replace MC74AC540NG in a 5 V system?
Yes, MC74ACT540NG can replace MC74AC540NG in 5 V systems, but only if TTL input compatibility is required. MC74ACT540NG has TTL-compatible inputs (VIH = 2.0 V), while MC74AC540NG requires CMOS-level inputs (VIH = 3.15 V @ 4.5 V). The MC74ACT540NG will correctly interpret LS-TTL outputs, whereas MC74AC540NG may misread them as LOW.
What is the thermal resistance (θJA) of MC74ACT540NG in SOIC-20W package?
The junction-to-ambient thermal resistance (θJA) for MC74ACT540NG in the SOIC-20W (Case 751D) package is 96 °C/W, measured per JESD 51-7 on a standard 4-layer JEDEC test board. This value assumes proper PCB copper pour and decoupling; actual θJA in custom layouts may vary by ±20 % depending on heatsinking and airflow. The MC74ACT540NG remains within safe operating limits up to +85 °C ambient when dissipating <150 mW.
MC74ACT540NG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- 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:
- Through Hole
- Supplier Device Package:
- 20-PDIP
MC74ACT540NG FAQ
1.How can I place an order for MC74ACT540NG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74ACT540NG 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 MC74ACT540NG reliable?
The price and inventory of MC74ACT540NG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74ACT540NG is usually 5 days.
3.What payment methods are accepted for MC74ACT540NG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74ACT540NG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74ACT540NG?
MC74ACT540NG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74ACT540NG 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 MC74ACT540NG?
For technical support, including MC74ACT540NG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74ACT540NG requirements.
6.How does Aetrix verify that MC74ACT540NG is sourced from the original manufacturer or authorized distributors?
All MC74ACT540NG 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 MC74ACT540NG meets industry standards.
7.What is the process for return or replacement of MC74ACT540NG?
All MC74ACT540NG units undergo pre-shipment inspection (PSI). If there is an issue with MC74ACT540NG, 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 MC74ACT540NG part is unused and in its original packaging.
Return procedure for MC74ACT540NG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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