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onsemi MC74AC540DW
- Part No.:
- MC74AC540DW
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MC74AC540DW.pdf
- Description:
- IC BUFF INVERT 6V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,009
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Product details
Overview
MC74AC540DW from onsemi is an octal inverting buffer/line driver with 3-state outputs, designed for memory and address bus driving, clock distribution, and microprocessor output port interfacing. It operates from 2.0 V to 6.0 V, delivers ±24 mA output drive per channel, 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 MC74AC540DW datasheet, pinout, applications, or equivalent options, this page provides verified functional identity, SOIC-20W package mapping, truth table behavior, 3-state timing parameters, and direct alternatives for bus interface design.
Technical Context
The MC74AC540DW implements eight independent inverting buffers, each with dual 3-state enable inputs (OE1 and OE2) controlling all outputs simultaneously. Its flow-through architecture places inputs on pins 1–10 and outputs on pins 11–18, enabling straight PCB trace routing from microprocessor data/address buses to peripheral loads.
It uses advanced CMOS technology for TTL-compatible voltage thresholds at 5 V (VIH = 2.1 V min, VIL = 0.9 V max), low quiescent ICC (≤80 µA), and fast propagation delays (tPLH/tPHL ≤ 6.5 ns at VCC = 5.0 V, CL = 50 pF). Output disable times (tPHZ/tPLZ) are specified down to 1.0 ns minimum, supporting high-speed bus arbitration.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Inverting octal buffer with dual 3-state control (OE1, OE2) |
| Supply Voltage Range | 2.0 V to 6.0 V - supports mixed-voltage system interfacing and legacy 5 V operation |
| Output Drive Strength | ±24 mA per output - sufficient to drive 50 Ω transmission lines or multiple TTL loads |
| Propagation Delay | ≤6.5 ns (tPLH/tPHL, VCC = 5.0 V, CL = 50 pF) - enables >100 MHz bus toggle rates |
| 3-State Enable/Disable Time | tPZH ≤ 9.5 ns, tPHZ ≤ 11 ns (VCC = 5.0 V) - ensures clean bus release during multiplexed access |
| Input Thresholds (5 V) | VIH = 2.1 V min, VIL = 0.9 V max - compatible with standard TTL and CMOS logic families |
| Package | SOIC-20 Wide Body (Case 751D) - industry-standard footprint with 12.8 mm × 7.5 mm body size |
Pinout & Package
MC74AC540DW is housed in a 20-pin SOIC-Wide (SOIC-20W) package (Case 751D), with 0.75 mm lead thickness, 1.27 mm pitch, and 12.8 mm × 7.5 mm body dimensions. Pin 1 is marked by a beveled corner or notch; pin 10 is GND, pin 20 is VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | Input A1–A8 | Inverting data inputs; accept standard CMOS/TTL logic levels |
| 9, 10 | OE1, OE2 | Active-low 3-state enables; both must be LOW to enable outputs |
| 11, 12, 13, 14, 15, 16, 17, 18 | Output Y1–Y8 | Inverted buffered outputs; enter high-impedance state when OE1 or OE2 is HIGH |
| 19 | GND | Ground reference for all I/O and supply terminals |
| 20 | VCC | Positive supply rail (2.0–6.0 V); decoupling capacitor required near pin |
Key Features
| Feature | Design Value |
|---|---|
| Inverting flow-through pinout | Inputs on left (pins 1–10), outputs on right (pins 11–18) - eliminates layer crossover in dense bus layouts |
| Dual 3-state enable control | OE1 and OE2 both active-low - allows redundant enable paths or OR-ed control from multiple sources |
| High-output current drive | ±24 mA per output - drives 15 pF load with <7 ns delay, supports fan-out of ≥10 LS-TTL loads |
| Pb-free and RoHS-compliant | "G" suffix indicates lead-free termination - meets IPC/JEDEC J-STD-020 reflow profile requirements |
| Wide supply voltage range | 2.0 V to 6.0 V operation - interoperable with 3.3 V microcontrollers and 5 V legacy peripherals |
Applications
| Memory Address Buffering | Microprocessor Output Port |
|---|---|
Use Scenario: Driving 16-bit address bus from an 8-bit microcontroller with external RAM/ROM expansion. IC Role / Device Role / Timing Role: Inverting octal buffer providing level translation and current gain between MCU port and memory chip address inputs. Use Value: Flow-through pinout allows direct left-to-right routing; ±24 mA drive ensures setup/hold timing margins across 10 cm PCB traces. |
Use Scenario: Isolating and driving parallel I/O lines from an 8051 or Z80-based embedded controller to LED arrays, relays, or sensors. IC Role / Device Role / Timing Role: 3-state output port expander enabling time-multiplexed sharing of a single data bus among multiple peripherals. Use Value: Dual OE inputs allow synchronized bus release; sub-10 ns disable time prevents bus contention during context switches. |
| Clock Distribution Network | Bus Transceiver Interface |
Use Scenario: Fan-out of a system clock signal to multiple synchronous logic blocks (e.g., UART, timer, ADC) requiring inverted clock edges. IC Role / Device Role / Timing Role: Low-skew inverting buffer ensuring matched propagation delay across all eight outputs. Use Value: tPLH/tPHL matching ≤0.5 ns (typ) minimizes clock skew; 3-state capability allows dynamic clock gating. |
Use Scenario: Bidirectional data bus isolation between two processor subsystems operating at different voltage domains (e.g., 3.3 V FPGA ↔ 5 V ASIC). IC Role / Device Role / Timing Role: Unidirectional inverting driver used in conjunction with complementary MC74AC541DW for full bus direction control. Use Value: Identical AC specs with MC74AC541DW enable matched timing in transceiver pairs; SOIC-20W footprint simplifies layout symmetry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC74AC540DWR2G | Same die, identical electrical specs, tape-and-reel packaging (1000 pcs/reel) vs. tube (38 pcs/rail) | No functional difference; optimized for automated SMT assembly | Select MC74AC540DWR2G for volume production; MC74AC540DW is tube-packaged for prototyping and low-volume use. |
| SN74AC540N | TI part with same logic function, but wider VCC range (2.0–6.0 V), slightly higher ICC (100 µA max), and longer tPHL (7.5 ns max at 5 V) | Compatible pinout and voltage thresholds; minor timing margin reduction in high-speed designs | Use SN74AC540N only if onsemi supply is constrained; verify tPHL margin in >80 MHz bus applications. |
Compared with MC74AC540DW, MC74AC540DWR2G offers identical performance in tape-and-reel format for SMT lines, while SN74AC540N provides second-source availability with acceptable timing trade-offs for non-critical bus speeds.
Availability
MC74AC540DW is available at Aetrix Electronics and suitable for memory expansion systems, microprocessor I/O port buffering, clock distribution networks, and bidirectional bus interface designs requiring stable component supply and long-term industrial lifecycle support.
Supply support for MC74AC540DW 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 sensor solutions for automotive, industrial, and cloud infrastructure markets.
The MC74AC540DW belongs to onsemi's 74AC logic family, engineered for high-speed, low-power, TTL-compatible CMOS interfacing in industrial and embedded control systems where reliability and wide supply tolerance are critical.
FAQ
What is the logic function of the MC74AC540DW?
The MC74AC540DW is an octal inverting buffer with 3-state outputs. Each of its eight channels accepts a digital input and produces an inverted output; all outputs enter high-impedance state when either OE1 or OE2 is driven HIGH. This function is confirmed in the truth table and functional description on page 1 of the onsemi datasheet MC74AC540/D Rev. 11.
Does the MC74AC540DW support 3.3 V operation?
Yes, the MC74AC540DW supports 3.3 V operation within its specified VCC range of 2.0 V to 6.0 V. At VCC = 3.3 V, it guarantees VIH ≥ 1.5 V and VIL ≤ 0.9 V, ensuring compatibility with 3.3 V CMOS logic families. These values are listed in the DC Characteristics table on page 4 of the MC74AC540/D datasheet.
What is the pinout configuration of the MC74AC540DW?
The MC74AC540DW uses a flow-through pinout: inputs A1–A8 and enables OE1/OE2 occupy pins 1–10 (left side), while inverted outputs Y1–Y8, VCC, and GND occupy pins 11–20 (right side). Pin 10 is GND, pin 20 is VCC. This layout is illustrated in Figure 1 on page 2 of the MC74AC540/D datasheet.
How does the MC74AC540DW differ from the MC74AC541DW?
The MC74AC540DW provides inverted outputs, whereas the MC74AC541DW provides noninverted outputs. Both share identical pinout, 3-state control, AC/DC specifications, and package. The functional distinction is explicitly stated in the datasheet introduction: "MC74AC540/74ACT540 Provides Inverted Outputs" and "MC74AC541/74ACT541 Provides Noninverted Outputs."
Is the MC74AC540DW RoHS compliant and Pb-free?
Yes, the MC74AC540DW is RoHS compliant and Pb-free, indicated by the "G" suffix in its full orderable part number MC74AC540DWG or MC74AC540DWR2G. The datasheet states "These are Pb−Free Devices" on page 1 and confirms compliance with JEDEC standards in the ordering information section on page 8.
MC74AC540DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74AC
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- 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:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
MC74AC540DW FAQ
1.How can I place an order for MC74AC540DW through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74AC540DW 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 MC74AC540DW reliable?
The price and inventory of MC74AC540DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74AC540DW is usually 5 days.
3.What payment methods are accepted for MC74AC540DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74AC540DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74AC540DW?
MC74AC540DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74AC540DW 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 MC74AC540DW?
For technical support, including MC74AC540DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74AC540DW requirements.
6.How does Aetrix verify that MC74AC540DW is sourced from the original manufacturer or authorized distributors?
All MC74AC540DW 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 MC74AC540DW meets industry standards.
7.What is the process for return or replacement of MC74AC540DW?
All MC74AC540DW units undergo pre-shipment inspection (PSI). If there is an issue with MC74AC540DW, 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 MC74AC540DW part is unused and in its original packaging.
Return procedure for MC74AC540DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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