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Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

onsemi MC74AC540DWR2

Name: MC74AC540DWR2
Brand: onsemi
SKU: MC74AC540DWR2
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MC74AC540DWR2

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-SOIC (0.295", 7.50mm Width)

Datasheet:: MC74AC540DWR2.pdf

Description:: IC BUFF INVERT 6V 20SOIC

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Product details

Overview

MC74AC540DWR2 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 2.0–6.0 V supply, delivers ±24 mA output drive per pin, features flow-through pinout (inputs on one side, outputs on the other), and supports industrial temperature range (−40°C to +85°C).

For engineers reviewing the MC74AC540DWR2 datasheet, pinout, applications, or equivalent options, key selection criteria include its inverting logic function, SOIC-20W package, 3-state enable control via dual OE inputs, high-speed propagation delay (≤6.5 ns at 5 V), and compatibility with AC-level CMOS logic families.

Technical Context

The MC74AC540DWR2 implements eight independent inverting buffers, each with a dedicated output-enable control path shared across two groups (OE1 controls Y1–Y4; OE2 controls Y5–Y8). Its flow-through architecture places all eight inputs on pins 1–8 and outputs on pins 13–20, enabling direct edge-aligned routing in microprocessor I/O port designs.

It uses standard AC CMOS technology with TTL-compatible input thresholds only in ACT variants - this part (AC) requires VIH ≥ 2.1 V at VCC = 4.5 V and exhibits typical propagation delays of 4.0 ns (tPLH/tPHL) and 6.5 ns (max) at 5 V/50 pF, with output enable/disable times under 9.5 ns.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Function	Inverting octal buffer with dual 3-state enable (OE1, OE2)
Supply Voltage Range	2.0 V to 6.0 V - supports mixed-voltage system interfacing and legacy 5 V rails
Output Drive	±24 mA per output - sufficient to drive 50 Ω transmission lines or multiple TTL loads
Propagation Delay	4.0 ns typical (tPLH/tPHL at VCC = 5.0 V, CL = 50 pF) - enables high-speed bus timing
3-State Enable Time	6.5 ns typical (tPZH/tPZL at VCC = 5.0 V) - minimizes bus contention during direction switching
Input Capacitance	4.5 pF - low loading on upstream drivers, preserves signal integrity in dense layouts
Operating Temperature	−40°C to +85°C - qualified for industrial-grade embedded control and instrumentation

Pinout & Package

MC74AC540DWR2 is housed in a 20-pin SOIC Wide Body (SOIC-20W, Case 751D) package measuring 12.8 mm × 7.5 mm × 2.5 mm, with 1.27 mm pitch and Pb-free finish (G suffix).

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8	Inputs (A1–A8)	Active-high data inputs; inverted at corresponding outputs
9, 10	Output Enables (OE1, OE2)	Low-active enables: OE1 controls Y1–Y4; OE2 controls Y5–Y8
11	GND	Ground reference for all I/O and internal circuitry
12	VCC	Positive supply rail (2.0–6.0 V); decoupling required near pin
13–16, 17–20	Outputs (Y1–Y4, Y5–Y8)	Inverted, 3-state outputs; high-impedance when respective OE is high

Key Features

Feature	Design Value
Inverting flow-through architecture	Inputs on left side (pins 1–8), outputs on right side (pins 13–20) - simplifies PCB trace routing for microprocessor port expansion
Dual independent 3-state control	OE1 and OE2 allow selective disabling of upper/lower nibbles - enables partial bus isolation without full shutdown
High-output current drive	±24 mA per output - eliminates need for external bus transceivers in moderate-load applications
Low dynamic power consumption	30 pF power dissipation capacitance (CPD) - reduces switching current and heat generation at 10 MHz operation
Pb-free and RoHS-compliant	Meets JESD22-A114 Human Body Model ESD rating >2000 V - suitable for automated assembly and field-replaceable modules

Applications

Memory Address Buffering	Microprocessor I/O Port Expansion
Use Scenario: Driving 16-bit address bus from an 8-bit microcontroller with external RAM/ROM. IC Role / Device Role / Timing Role: Inverting octal buffer providing level translation and fanout amplification between CPU address latch and memory chip inputs. Use Value: Dual OE control allows interleaved access to upper/lower memory banks; flow-through pinout minimizes trace skew across address lines.	Use Scenario: Expanding GPIO capability of an 8-bit MCU to control 8 peripheral devices via shared data bus. IC Role / Device Role / Timing Role: Bidirectional bus driver acting as output port with 3-state isolation during read cycles. Use Value: ±24 mA drive ensures reliable logic levels across 10 cm PCB traces; fast enable/disable (<9.5 ns) prevents bus contention during direction changes.
Industrial Bus Transceiver Interface	Legacy System Clock Distribution
Use Scenario: Isolating and buffering RS-485 or CAN controller signals before differential line drivers. IC Role / Device Role / Timing Role: Signal conditioner and level shifter between logic-side controller and physical-layer transceiver ICs. Use Value: High noise immunity (VIH = 2.1 V min at 4.5 V) and 4.5 pF input capacitance preserve signal edge rate in noisy factory environments.	Use Scenario: Distributing a 25 MHz system clock to multiple synchronous peripherals with matched trace lengths. IC Role / Device Role / Timing Role: Low-skew clock buffer replicating and inverting clock edges for complementary timing domains. Use Value: 4.0 ns typical propagation delay and <0.5 ns channel-to-channel skew ensure setup/hold margin compliance across 8 downstream loads.

Memory Address Buffering

Microprocessor I/O Port Expansion

Use Scenario: Driving 16-bit address bus from an 8-bit microcontroller with external RAM/ROM.

IC Role / Device Role / Timing Role: Inverting octal buffer providing level translation and fanout amplification between CPU address latch and memory chip inputs.

Use Value: Dual OE control allows interleaved access to upper/lower memory banks; flow-through pinout minimizes trace skew across address lines.

Use Scenario: Expanding GPIO capability of an 8-bit MCU to control 8 peripheral devices via shared data bus.

IC Role / Device Role / Timing Role: Bidirectional bus driver acting as output port with 3-state isolation during read cycles.

Use Value: ±24 mA drive ensures reliable logic levels across 10 cm PCB traces; fast enable/disable (<9.5 ns) prevents bus contention during direction changes.

Industrial Bus Transceiver Interface

Legacy System Clock Distribution

Use Scenario: Isolating and buffering RS-485 or CAN controller signals before differential line drivers.

IC Role / Device Role / Timing Role: Signal conditioner and level shifter between logic-side controller and physical-layer transceiver ICs.

Use Value: High noise immunity (VIH = 2.1 V min at 4.5 V) and 4.5 pF input capacitance preserve signal edge rate in noisy factory environments.

Use Scenario: Distributing a 25 MHz system clock to multiple synchronous peripherals with matched trace lengths.

IC Role / Device Role / Timing Role: Low-skew clock buffer replicating and inverting clock edges for complementary timing domains.

Use Value: 4.0 ns typical propagation delay and <0.5 ns channel-to-channel skew ensure setup/hold margin compliance across 8 downstream loads.

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal inverting buffer applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MC74AC540DWG	Same die, SOIC-20W rail-packaged variant (38 units/rail vs. 1000/reel)	No functional difference; differs only in packaging format and reel quantity	Select MC74AC540DWG for prototyping or low-volume manual assembly where tape-and-reel handling is impractical
SN74AC540N	Texas Instruments' pin-compatible octal inverting buffer; identical logic function and SOIC-20 package but different AC timing specs (tPLH max 7.5 ns @ 5 V)	Valid for drop-in replacement where 1.0 ns higher propagation delay is acceptable	Choose SN74AC540N when sourcing diversification is required and timing budget allows ≤7.5 ns max delay

Compared with MC74AC540DWR2, MC74AC540DWG offers identical electrical performance in a different logistics format, while SN74AC540N provides second-source availability with slightly relaxed timing - both require no PCB redesign but differ in supply chain lead time and qualification documentation scope.

Availability

MC74AC540DWR2 is available at Aetrix Electronics and suitable for industrial control panels, legacy microprocessor-based instrumentation, and automotive body electronics requiring stable component supply across extended product lifecycles.

Supply support for MC74AC540DWR2 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, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MC74AC540DWR2 belongs to onsemi's legacy AC logic family, engineered for robustness in industrial and automotive subsystems where wide supply voltage tolerance, high noise immunity, and long-term component availability are critical design requirements.

FAQ

What logic function does the MC74AC540DWR2 implement?

The MC74AC540DWR2 implements eight independent inverting buffers, each with 3-state output control. Inputs A1–A8 appear inverted at outputs Y1–Y8 when the corresponding OE input (OE1 for Y1–Y4, OE2 for Y5–Y8) is low. When either OE is high, the associated outputs enter high-impedance state. This behavior is confirmed in the truth table and functional description on page 1 of the onsemi datasheet.

What package type and dimensions does the MC74AC540DWR2 use?

The MC74AC540DWR2 uses a SOIC-20 Wide Body (SOIC-20W) package, designated Case 751D, with 1.27 mm lead pitch, overall dimensions of 12.8 mm × 7.5 mm × 2.5 mm, and Pb-free finish. This is explicitly stated in the Ordering Information table (page 8) and mechanical drawing (page 8) of the official onsemi datasheet.

Does the MC74AC540DWR2 support 3.3 V operation?

Yes, the MC74AC540DWR2 supports 3.3 V operation within its specified supply range of 2.0 V to 6.0 V. At VCC = 3.3 V, the minimum high-level input voltage (VIH) is guaranteed at 1.5 V, and propagation delay is 5.5 ns (typical) per the AC Characteristics table on page 5 of the onsemi datasheet.

How are the output-enable inputs configured on the MC74AC540DWR2?

The MC74AC540DWR2 has two active-low output-enable inputs: OE1 (pin 9) controls outputs Y1–Y4, and OE2 (pin 10) controls outputs Y5–Y8. Both must be low for their respective outputs to be active and inverted; if either is high, the corresponding group enters high-impedance state. This dual-enable structure is defined in the truth table (page 1) and pin diagram (Figure 1, page 2).

What is the maximum output current rating for the MC74AC540DWR2?

The MC74AC540DWR2 is rated for ±24 mA DC output current per pin under recommended operating conditions (VCC = 4.5–5.5 V, TA = −40°C to +85°C), as specified in the Recommended Operating Conditions table on page 3 of the onsemi datasheet. Absolute maximum ratings allow ±50 mA, but sustained operation above ±24 mA is not guaranteed.

MC74AC540DWR2 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74AC

Package/Case:: 20-SOIC (0.295", 7.50mm Width)

Packaging:: Tape & Reel (TR)

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:: 2V ~ 6V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOIC

MC74AC540DWR2 FAQ

1.How can I place an order for MC74AC540DWR2 through Aetrix?

Please submit a Request for Quotation (RFQ) for MC74AC540DWR2 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 MC74AC540DWR2 reliable?

The price and inventory of MC74AC540DWR2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74AC540DWR2 is usually 5 days.

3.What payment methods are accepted for MC74AC540DWR2?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74AC540DWR2 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MC74AC540DWR2?

MC74AC540DWR2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MC74AC540DWR2 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 MC74AC540DWR2?

For technical support, including MC74AC540DWR2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74AC540DWR2 requirements.

6.How does Aetrix verify that MC74AC540DWR2 is sourced from the original manufacturer or authorized distributors?

All MC74AC540DWR2 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 MC74AC540DWR2 meets industry standards.

7.What is the process for return or replacement of MC74AC540DWR2?

All MC74AC540DWR2 units undergo pre-shipment inspection (PSI). If there is an issue with MC74AC540DWR2, 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 MC74AC540DWR2 part is unused and in its original packaging.

Return procedure for MC74AC540DWR2:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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