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onsemi MC74HC540AFG
- Part No.:
- MC74HC540AFG
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MC74HC540AFG.pdf
- Description:
- IC BUFFER INVERT 6V SOEIAJ-20
- Quantity:
- Payment:
- Shipping:
Inventory:4,682
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Product details
Overview
MC74HC540AFG from onsemi is an octal 3-state inverting buffer/line driver/line receiver in a TSSOP-20 package, operating from 2.0 V to 6.0 V, delivering ±7.8 mA output drive at 6.0 V, with propagation delay as low as 15 ns (VCC = 6.0 V), and designed for bus-oriented systems including memory address and clock distribution.
For engineers reviewing the MC74HC540AFG datasheet, pinout, applications, or equivalent options, key selection criteria include dual active-low output enables (OE1/OE2), high-noise-immunity CMOS inputs compatible with LSTTL and standard CMOS, and guaranteed operation across −55 °C to +125 °C industrial temperature range.
Technical Context
The MC74HC540AFG implements eight independent inverting buffers, each with high-impedance (3-state) outputs controlled by two ANDed active-low enables - both OE1 and OE2 must be low for output enable. Its silicon-gate CMOS architecture ensures low static current (ICC ≤ 160 µA at 6.0 V, 125 °C) and high noise immunity per JEDEC Std. 7A.
Input thresholds scale with VCC (VIH = 0.7×VCC min, VIL = 0.3×VCC max), supporting robust interfacing across 2.0–6.0 V supply rails. Propagation delays (tPLH/tPHL) are specified down to 15 ns at 6.0 V, with output transition times (tTLH/tTHL) as fast as 10 ns, enabling reliable timing in high-speed bus applications up to ~33 MHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.0 V to 6.0 V - supports mixed-voltage system interfacing and battery-powered designs with wide headroom. |
| Output Drive Capability | ±7.8 mA at VCC = 6.0 V - drives 15 LSTTL loads directly without external buffering. |
| Propagation Delay (A→Y) | 15 ns max at VCC = 6.0 V - enables reliable operation in 33 MHz bus cycles with margin. |
| Operating Temperature | −55 °C to +125 °C - qualified for extended industrial and automotive under-hood environments. |
| Input Leakage Current | ±1.0 µA max at 6.0 V, 125 °C - ensures stable logic levels with high-impedance inputs and minimal power impact. |
| 3-State Output Leakage | ±10.0 µA max at 6.0 V, 125 °C - prevents unintended loading of shared buses during disable state. |
| Power Dissipation Capacitance | 35 pF per buffer - enables accurate dynamic power estimation (PD = CPD × VCC² × f + ICC × VCC). |
Pinout & Package
TSSOP-20 package (Case 948E), 0.65 mm pitch, 6.5 mm × 4.4 mm footprint, 1.2 mm max height, Pb-free and RoHS compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1, OE2 | ANDed active-low output enables - both must be low for Y1–Y8 to drive; either high forces all outputs into high-impedance. |
| 2–9 | A1–A8 | Inverting data inputs - logic level inverted and driven to corresponding Y outputs when enabled. |
| 11–18 | Y1–Y8 | Inverting buffered outputs - present A1–A8 complement when enabled; high-Z otherwise. |
| 10 | GND | Ground reference for all I/O and internal circuitry - must be low-impedance connection. |
| 20 | VCC | Positive supply rail - decoupling capacitor (0.1 µF ceramic) required near pin for noise suppression. |
Key Features
| Feature | Design Value |
|---|---|
| Octal inverting 3-state architecture | Enables bidirectional bus control with direction-independent signal inversion and isolation via OE gating. |
| Dual ANDed active-low output enables | Prevents accidental bus contention by requiring coordinated enable signaling - improves system-level fault tolerance. |
| CMOS input compatibility with LSTTL | Eliminates need for pull-up resistors when interfacing with legacy TTL logic - simplifies mixed-technology board design. |
| High noise immunity (JEDEC Std. 7A) | Ensures reliable operation in electrically noisy industrial environments with >400 mV noise margin at 4.5 V supply. |
| AEC-Q100 qualified variant available | Supports automotive applications requiring PPAP documentation and traceable manufacturing controls (MC74HC540ADTR2G−Q). |
Applications
| Memory Address Buffering | Clock Distribution Network |
|---|---|
Use Scenario: Driving multiplexed address lines from a microcontroller to SRAM or Flash memory in embedded systems with space-constrained PCB layouts. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating CPU address bus from memory while enabling chip select arbitration. Use Value: Prevents bus contention during memory access transitions and reduces capacitive loading on address lines via low-output-capacitance (15 pF) 3-state outputs. | Use Scenario: Distributing a single system clock to multiple peripherals (e.g., ADC, UART, GPIO expanders) with matched skew and fanout control. IC Role / Device Role / Timing Role: Low-skew inverting clock driver with enable-controlled gating for power-aware peripheral clock gating. Use Value: Enables precise clock enable/disable sequencing (via OE1/OE2) and maintains <15 ns propagation delay variation across all eight outputs at 6.0 V. |
| Industrial Bus Interface | Legacy System Signal Translation |
Use Scenario: Interfacing modern 3.3 V microcontrollers with older 5 V industrial PLC backplanes using shared data/address buses. IC Role / Device Role / Timing Role: Level-translating inverting buffer with 2.0–6.0 V supply flexibility and LSTTL-compatible inputs. Use Value: Eliminates external level shifters - direct interface to 5 V LSTTL with 15 mA drive capability and guaranteed VIH/VIL thresholds scaling with VCC. | Use Scenario: Replacing obsolete 74LS540 in legacy test equipment where pinout compatibility and functional equivalence are mandatory. IC Role / Device Role / Timing Role: Drop-in CMOS upgrade for LS-TTL octal inverting buffer with identical SOIC-20/TSSOP-20 pinout and logic function. Use Value: Reduces system power consumption by >90% versus LS540 while maintaining full pin-to-pin and functional compatibility - no PCB redesign required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC540N | Dual OE inputs tied internally to single OE; only one active-low enable pin (pin 1), no OE2 pin - different pinout and control logic. | Not pin-compatible; requires PCB layout change and firmware logic update for enable handling. | Select when single-enable simplicity outweighs dual-OE fault tolerance and board reuse is not required. |
| MC74HC240AFG | Identical pinout, dual active-low OE, same TSSOP-20 package, but features non-inverting A→Y path (vs. inverting in MC74HC540AFG). | Functional replacement only where signal polarity inversion is undesirable or compensated elsewhere in the signal chain. | Choose for non-inverting bus buffering; verify downstream logic accommodates polarity change or add external inversion. |
Compared with SN74HC540N and MC74HC240AFG, the MC74HC540AFG uniquely provides dual ANDed active-low enables in a pin-compatible drop-in replacement for 74LS540, with guaranteed inverting behavior and full industrial temperature support - critical for legacy upgrades and fault-tolerant bus designs.
Availability
MC74HC540AFG is available at Aetrix Electronics and suitable for memory address buffering, clock distribution networks, industrial bus interfaces, and legacy system signal translation requiring stable component supply and long-term lifecycle assurance.
Supply support for MC74HC540AFG 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 electronics, delivering high-performance analog, logic, discrete, and custom devices for automotive, industrial, cloud, and consumer markets.
The MC74HC540AFG belongs to onsemi's HC-series high-speed CMOS logic family, engineered for low-power, high-noise-immunity bus interfacing in industrial and automotive control systems where reliability and wide supply voltage operation are essential.
FAQ
What is the pinout configuration of the MC74HC540AFG?
The MC74HC540AFG uses a TSSOP-20 package with pins 1 and 19 as active-low output enables (OE1, OE2), pins 2–9 as inverting inputs (A1–A8), pins 11–18 as inverting outputs (Y1–Y8), pin 10 as GND, and pin 20 as VCC. This matches the industry-standard 74LS540 pinout, enabling direct replacement in legacy designs.
Does the MC74HC540AFG support 3.3 V operation?
Yes, the MC74HC540AFG operates over 2.0 V to 6.0 V, making it fully compatible with 3.3 V systems. At VCC = 3.3 V, it delivers ±6.0 mA output drive, meets VIH ≥ 2.31 V and VIL ≤ 0.99 V, and maintains propagation delay ≤ 23 ns - verified across −55 °C to +125 °C.
How does the dual output enable (OE1/OE2) function in the MC74HC540AFG?
In the MC74HC540AFG, both OE1 and OE2 must be logic low to enable the inverting outputs Y1–Y8. If either OE1 or OE2 is high, all outputs enter high-impedance state. This ANDed enable logic prevents accidental bus contention and supports redundant or synchronized enable control in safety-critical systems.
Is the MC74HC540AFG pin-compatible with the 74LS540?
Yes, the MC74HC540AFG is identical in pinout to the 74LS540 and designed as a direct CMOS upgrade. It retains the same SOIC-20 and TSSOP-20 footprints, identical pin numbering, and matching logic function - allowing drop-in replacement without PCB modification or schematic changes.
What is the maximum operating temperature for the MC74HC540AFG?
MC74HC540AFG is rated for operation from −55 °C to +125 °C across all package types, including the TSSOP-20 variant. This extended temperature range is validated per onsemi's industrial qualification standards and supports deployment in harsh environments such as motor control enclosures and outdoor industrial automation equipment.
MC74HC540AFG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74HC
- Package/Case:
- 20-SOIC (0.209", 5.30mm 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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOEIAJ-20
MC74HC540AFG FAQ
1.How can I place an order for MC74HC540AFG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74HC540AFG 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 MC74HC540AFG reliable?
The price and inventory of MC74HC540AFG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74HC540AFG is usually 5 days.
3.What payment methods are accepted for MC74HC540AFG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74HC540AFG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74HC540AFG?
MC74HC540AFG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74HC540AFG 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 MC74HC540AFG?
For technical support, including MC74HC540AFG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74HC540AFG requirements.
6.How does Aetrix verify that MC74HC540AFG is sourced from the original manufacturer or authorized distributors?
All MC74HC540AFG 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 MC74HC540AFG meets industry standards.
7.What is the process for return or replacement of MC74HC540AFG?
All MC74HC540AFG units undergo pre-shipment inspection (PSI). If there is an issue with MC74HC540AFG, 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 MC74HC540AFG part is unused and in its original packaging.
Return procedure for MC74HC540AFG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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