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onsemi MC74ACT540N
- Part No.:
- MC74ACT540N
- Manufacturer:
- onsemi
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
MC74ACT540N.pdf
- Description:
- IC BUFF INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,820
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Product details
Overview
MC74ACT540N from onsemi is an octal inverting buffer/line driver with 3-state outputs, designed for memory and address bus driving, clock distribution, and bidirectional bus interfacing in microprocessor systems. It operates at 4.5 V to 5.5 V, delivers ±24 mA output drive, supports flow-through pinout (inputs on one side, outputs on the other), and features TTL-compatible inputs.
For engineers reviewing the MC74ACT540N datasheet, pinout, applications, or equivalent options, this page provides verified functional identity, SOIC-20 package mapping, confirmed 3-state timing parameters (tPZH ≤ 11.5 ns), inverted logic behavior, and direct alternatives for bus interface design.
Technical Context
The MC74ACT540N implements eight independent inverting buffers, each with separate 3-state control via dual active-low OE inputs (OE1 and OE2). Its flow-through architecture places all eight inputs on pins 1–8 and outputs on pins 13–20, enabling straight-line PCB routing from microprocessor data/address buses to peripheral devices.
It uses ACT (Advanced CMOS TTL-compatible) logic, ensuring VIH = 2.0 V min and VIL = 0.8 V max at VCC = 4.5–5.5 V, while maintaining rail-to-rail VOH ≥ 4.4 V and VOL ≤ 0.44 V under ±24 mA load - critical for noise-immune 5 V digital system interconnects.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Inverting octal buffer with dual 3-state enable (OE1, OE2) |
| Supply Voltage Range | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL/CMOS systems |
| Output Drive | ±24 mA - sufficient to drive 50 Ω transmission lines or multiple 74-series loads |
| Propagation Delay | tPLH/tPHL ≤ 7.5 ns @ VCC = 5.0 V, CL = 50 pF - enables >100 MHz bus operation |
| 3-State Enable Time | tPZH/tPZL ≤ 11.5 ns - minimizes bus contention during direction switching |
| Input Compatibility | TTL-compatible (VIH = 2.0 V, VIL = 0.8 V) - interfaces directly with legacy 74LS/TTL logic |
| Package | SOIC-20 (Case 751D) - industry-standard 0.300″ wide surface-mount footprint |
Pinout & Package
MC74ACT540N is housed in a 20-pin SOIC Wide Body (Case 751D) package, 12.8 mm × 7.5 mm × 2.5 mm, with 1.27 mm pitch, Pb-free finish, and moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | Inputs (D1–D8) | Inverting data inputs - connect directly to microprocessor data/address bus lines |
| 9, 10 | OE1, OE2 | Active-low 3-state enables - both must be LOW for output assertion; independent control per half-bank |
| 11 | GND | Ground reference - decoupling capacitor required adjacent to pin |
| 12 | NC | No connect - internal die pad, left unconnected per datasheet |
| 13, 14, 15, 16, 17, 18, 19, 20 | Outputs (Y1–Y8) | Inverted buffered outputs - drive external bus lines or peripheral inputs with ±24 mA capability |
| 20 | VCC | Positive supply - requires local 0.1 µF ceramic bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| Inverting flow-through architecture | Inputs on left (pins 1–8), outputs on right (pins 13–20) - eliminates layer jumps and reduces trace length in microprocessor port layouts |
| Dual independent 3-state enables | OE1 controls Y1–Y4; OE2 controls Y5–Y8 - enables split-bus control without external gating |
| TTL-compatible input thresholds | VIH = 2.0 V, VIL = 0.8 V @ 5 V - ensures reliable interfacing with 74LS, 74F, and microcontroller GPIOs |
| Rail-to-rail output swing | VOH ≥ 4.4 V, VOL ≤ 0.44 V @ ±24 mA - maintains noise margin >0.4 V in noisy industrial 5 V environments |
| Pb-free SOIC-20 package | RoHS-compliant, MSL Level 1 - supports lead-free reflow and long-term supply continuity |
Applications
| Microprocessor Data Bus Interface | Memory Address Latching |
|---|---|
Use Scenario: Bidirectional data transfer between an 8-bit microcontroller (e.g., 8051 or PIC18) and external SRAM or flash memory. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating MCU data bus from memory bus; enables read/write direction control via OE1/OE2 timing. Use Value: Eliminates need for discrete direction-control logic; ±24 mA drive ensures clean signal integrity across 10 cm PCB traces. |
Use Scenario: Driving 8-bit address lines from a microcontroller to multiple peripheral ICs sharing a common address space. IC Role / Device Role / Timing Role: Address line driver with 3-state disable during interrupt service or DMA cycles to prevent bus conflicts. Use Value: Dual OE inputs allow selective disabling of upper/lower address segments, reducing contention risk in multi-peripheral systems. |
| Legacy System Bus Expansion | Industrial I/O Port Buffering |
Use Scenario: Extending a vintage 8-bit ISA or S-100 bus with additional peripheral slots requiring TTL-level signal conditioning. IC Role / Device Role / Timing Role: Inverting buffer providing level translation and fanout amplification for address/data/control signals. Use Value: TTL-compatible inputs accept 74LS logic levels; 7.5 ns propagation delay preserves timing margins in 8 MHz bus systems. |
Use Scenario: Isolating PLC CPU I/O pins from field-side sensors and actuators subject to EMI and voltage transients. IC Role / Device Role / Timing Role: Output port driver with 3-state disable during fault conditions or configuration changes. Use Value: High-impedance state prevents back-driving during hot-swap or diagnostics; ±24 mA sink/source handles LED indicators and relay coils directly. |
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 | Identical logic function, pinout, and DC/AC specs; manufactured by Texas Instruments | Same 5 V bus driving use cases; TI's version has identical thermal resistance (96 °C/W) and MSL Level 1 | Select when dual-sourcing is required or TI's logistics terms are preferred |
| MC74ACT240N | Two groups of four inverting buffers (vs. single group of eight); shares same SOIC-20 package and ACT family specs | Better suited for split-bus architectures where independent control of two 4-bit lanes is needed | Choose when system layout benefits from separate OE control per 4-bit segment rather than unified 8-bit enable |
Compared with SN74ACT540N and MC74ACT240N, the MC74ACT540N offers unified 8-bit inversion and single-package density ideal for compact microprocessor port expansion, whereas SN74ACT540N provides second-source assurance and MC74ACT240N enables finer-grained bus segmentation.
Availability
MC74ACT540N is available at Aetrix Electronics and suitable for microprocessor bus interface, memory subsystem expansion, and industrial I/O port buffering requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for MC74ACT540N 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 power management, analog, sensor, and logic solutions for automotive, industrial, and computing markets.
The MC74ACT540N belongs to onsemi's Advanced CMOS (ACT) logic family, engineered for high-speed, low-power 5 V digital interfacing with TTL compatibility - targeting legacy system upgrades and robust industrial control designs.
FAQ
What is the logic function of the MC74ACT540N?
The MC74ACT540N is an octal inverting buffer with 3-state outputs. Each of its eight channels accepts a digital input on pins 1–8, inverts it, and drives the corresponding output on pins 13–20 when enabled. Dual active-low OE inputs (pins 9 and 10) control output enablement in two independent 4-bit groups. This function makes the MC74ACT540N ideal for bidirectional bus isolation and memory address/data driving in 5 V systems.
Does the MC74ACT540N support 3.3 V operation?
No, the MC74ACT540N is not rated for 3.3 V operation. Its recommended supply voltage range is strictly 4.5 V to 5.5 V, and its TTL-compatible inputs require VIH ≥ 2.0 V and VIL ≤ 0.8 V - specifications guaranteed only within that 5 V range. Using the MC74ACT540N below 4.5 V may result in undefined logic states or degraded noise immunity. For 3.3 V systems, consider the MC74LCX540 or SN74LVC541 instead.
What is the maximum output current rating for the MC74ACT540N?
The MC74ACT540N is specified to source or sink up to ±24 mA per output pin under recommended operating conditions (VCC = 4.5–5.5 V, TA = −40°C to +85°C). This value is guaranteed in the DC Characteristics table and reflects steady-state drive capability into resistive loads. Peak dynamic current can reach ±75 mA for short durations (≤2 ms), but continuous operation must remain within the ±24 mA limit to ensure VOH ≥ 4.4 V and VOL ≤ 0.44 V.
Is the MC74ACT540N pin-compatible with the MC74AC540N?
Yes, the MC74ACT540N is pin-compatible with the MC74AC540N - both share identical SOIC-20 pinout, input/output assignment, and dual-OE architecture. However, they differ electrically: the MC74ACT540N has TTL-compatible inputs (VIH = 2.0 V), while the MC74AC540N has CMOS inputs (VIH = 3.15 V @ 4.5 V). Thus, direct substitution is safe only if the driving logic meets the stricter AC540 input threshold requirements.
What package options are available for the MC74ACT540N?
The MC74ACT540N is offered exclusively in the SOIC-20 Wide Body package (Case 751D), with Pb-free finish and moisture sensitivity level 1. Datasheet ordering codes include MC74ACT540DWG (rail) and MC74ACT540DWR2G (tape & reel). Unlike some variants in the same family (e.g., MC74ACT540DTR2G), the MC74ACT540N suffix denotes the SOIC-20 variant and does not support TSSOP-20 or other footprints.
MC74ACT540N 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
MC74ACT540N FAQ
1.How can I place an order for MC74ACT540N through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74ACT540N 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 MC74ACT540N reliable?
The price and inventory of MC74ACT540N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74ACT540N is usually 5 days.
3.What payment methods are accepted for MC74ACT540N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74ACT540N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74ACT540N?
MC74ACT540N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74ACT540N 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 MC74ACT540N?
For technical support, including MC74ACT540N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74ACT540N requirements.
6.How does Aetrix verify that MC74ACT540N is sourced from the original manufacturer or authorized distributors?
All MC74ACT540N 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 MC74ACT540N meets industry standards.
7.What is the process for return or replacement of MC74ACT540N?
All MC74ACT540N units undergo pre-shipment inspection (PSI). If there is an issue with MC74ACT540N, 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 MC74ACT540N part is unused and in its original packaging.
Return procedure for MC74ACT540N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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