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onsemi 74VHCT540AMX
- Part No.:
- 74VHCT540AMX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
74VHCT540AMX.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,376
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Product details
Overview
74VHCT540AMX from Fairchild Semiconductor is an octal non-inverting 3-STATE buffer/line driver in 20-lead SOIC package, operating at 4.5–5.5V supply, with 5.4ns typical propagation delay, ±25mA output drive, and input/output voltage tolerance up to 7.0V. It serves as a bidirectional bus interface or microprocessor output port in memory address/data path applications.
For engineers reviewing the 74VHCT540AMX datasheet, pinout, applications, or equivalent options, key selection criteria include 3-STATE timing (tPZL/tPLZ ≤ 14ns), input protection for 3V/5V mixed-supply interfacing, low ICC (4µA max), and flow-through pin architecture enabling compact PCB layout.
Technical Context
The 74VHCT540AMX implements dual active-low 3-STATE enable inputs (OE1, OE2) controlling eight independent non-inverting buffers. Its silicon gate CMOS process delivers TTL-compatible speed while maintaining CMOS-level static power consumption.
Input and output pins tolerate –0.5V to +7.0V regardless of VCC, enabling safe level-shifting between 3V and 5V domains and battery-backup system interfacing. The flow-through pinout places I0–I7 on one side and O0–O7 on the opposite side, minimizing trace crossovers in microprocessor port designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - Ensures compatibility with standard 5V TTL logic rails and noise margin compliance. |
| Propagation Delay | 5.4ns (typ.) at VCC = 5V, CL = 15pF - Enables high-speed address/data buffering in 20+ MHz bus systems. |
| Output Drive | ±25mA per output - Supports direct connection to 50Ω transmission lines or multiple TTL loads without external drivers. |
| 3-STATE Enable Time | 8.3ns (typ.) - Minimizes bus contention window during direction switching in bidirectional data transfers. |
| Input Leakage | ±1.0µA max at TA = –40°C to +85°C - Guarantees reliable logic levels with high-impedance pull-ups or open-drain interfaces. |
| VIN/VOUT Tolerance | –0.5V to +7.0V - Allows hot-swap and mixed-voltage operation without external clamping diodes. |
Pinout & Package
74VHCT540AMX is housed in a 20-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" wide (Package Number M20B), with 1.27mm lead pitch and surface-mount footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1, OE2 | Active-low 3-STATE enable inputs - Both must be LOW to activate all eight outputs; independent control not supported. |
| 2–9 | I0–I7 | Buffer inputs - Non-inverting; accept 3V/5V logic levels with overvoltage tolerance up to 7V. |
| 11–18 | O0–O7 | 3-STATE outputs - High-impedance when OE1/OE2 HIGH; drive ±25mA when enabled. |
| 10 | GND | Ground reference - Must be connected to system ground plane for noise immunity and ESD protection. |
| 20 | VCC | Positive supply - Requires 4.5–5.5V; decoupling capacitor (0.1µF) recommended adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Flow-through pinout | Inputs (pins 2–9) and outputs (pins 11–18) on opposite sides - Reduces PCB trace length and layer count in microprocessor I/O expansion. |
| Overvoltage-tolerant I/O | –0.5V to +7.0V input/output rating - Eliminates need for external level-shifters or clamping circuits in mixed-supply systems. |
| Ultra-low quiescent current | 4µA max ICC at TA = 25°C - Enables use in battery-backed or always-on subsystems without significant standby drain. |
| Power-down protection | Functional I/O protection when VCC = 0V - Prevents back-powering and latch-up during hot-insertion or partial power loss. |
Applications
| Memory Address Buffering | Microprocessor Output Port |
|---|---|
|
Use Scenario: Driving 16-bit address bus from a microcontroller to SRAM or EPROM with fanout >10. IC Role / Device Role / Timing Role: Non-inverting octal buffer with simultaneous 3-STATE control - isolates CPU from memory during DMA cycles. Use Value: 5.4ns tPD ensures setup/hold timing margins at 25MHz bus clock; ±25mA drive sustains signal integrity across 10cm traces. |
Use Scenario: Expanding GPIO capability of an 8-bit MCU to control LED arrays, relays, or peripheral enable lines. IC Role / Device Role / Timing Role: 3-STATE line driver - allows shared bus access among multiple peripherals via OE control. Use Value: Flow-through pinout simplifies routing on 2-layer PCBs; 7V I/O tolerance prevents damage from relay coil flyback transients. |
| 5V/3V Level Translation | Bus Transceiver Interface |
|
Use Scenario: Interfacing a 3.3V FPGA I/O bank to legacy 5V peripheral logic without external resistors. IC Role / Device Role / Timing Role: Unidirectional voltage-tolerant buffer - accepts 3.3V inputs and drives 5V-compatible outputs. Use Value: VIH = 2.0V min and VIL = 0.8V max ensure robust logic recognition; no level-shifter IC or BOM overhead required. |
Use Scenario: Isolating a shared data bus between two microcontrollers in a redundant control system. IC Role / Device Role / Timing Role: Bidirectional bus driver with synchronized 3-STATE control - enables clean bus arbitration. Use Value: tPZL/tPLZ ≤ 14ns limits bus turnaround time; ±25mA drive supports termination resistors and stub loading. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-STATE buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT540N | Same pinout and logic function; slightly higher ICC (8µA max) and slower tPD (8ns typ. at 5V). | Valid for legacy 5V-only systems where ultra-low power is secondary to second-source availability. | Select when TI's long-term supply assurance or existing qualification in automotive ECUs is required. |
| 74LCX541MTCX | Lower VCC range (2.0–3.6V); 3.3V-only operation; 5.5ns tPD; 24mA drive; TSSOP-20 package. | Designed for 3.3V systems only; not tolerant of 5V inputs/outputs. | Choose for new 3.3V designs requiring lower supply voltage and reduced power, but requires redesign for 5V compatibility. |
Compared with SN74HCT540N and 74LCX541MTCX, the 74VHCT540AMX uniquely combines 5V operation, 7V I/O tolerance, and 4µA ICC - making it optimal for mixed-voltage industrial controllers where reliability under voltage mismatch is critical.
Availability
74VHCT540AMX is available at Aetrix Electronics and suitable for memory address buffering, microprocessor I/O expansion, 5V/3V level translation, and bus transceiver interface applications requiring stable component supply and long-lifecycle support.
Supply support for 74VHCT540AMX 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and discrete power products before its acquisition by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and computing infrastructure.
The 74VHCT540AMX belongs to Fairchild's VHCT (Very High-Speed CMOS TTL-compatible) logic family, engineered for drop-in replacement of bipolar TTL in high-speed, low-power 5V digital systems with enhanced noise immunity and voltage tolerance.
FAQ
What is the maximum operating temperature range for the 74VHCT540AMX?
The 74VHCT540AMX is rated for continuous operation from –40°C to +85°C. This industrial temperature range ensures reliable performance in factory automation controllers, motor drives, and outdoor communication equipment where ambient thermal stress exceeds commercial-grade limits. All DC and AC specifications in the datasheet are guaranteed across this full range.
Does the 74VHCT540AMX support true bidirectional data transfer?
No, the 74VHCT540AMX is a unidirectional octal buffer: signals flow only from I0–I7 to O0–O7. It lacks internal direction control or bus-hold circuitry. For bidirectional applications, two 74VHCT540AMX devices (one per direction) or a dedicated transceiver like the 74VHCT245AMX must be used with external direction logic.
Can the 74VHCT540AMX be used with a 3.3V supply voltage?
No - the 74VHCT540AMX requires VCC between 4.5V and 5.5V. Its input thresholds (VIH = 2.0V, VIL = 0.8V) and output drive strength are specified only within that range. Applying 3.3V to VCC may result in undefined logic states, excessive ICC, or failure to meet timing specs. Use 74LCX541 or 74ALVC541 for 3.3V operation.
What is the purpose of the dual OE inputs (OE1 and OE2) on the 74VHCT540AMX?
The 74VHCT540AMX uses OE1 and OE2 as logically OR'd active-low enables: both must be LOW to enable all eight outputs. They are not independent controls. This design simplifies global bus enable logic - a single inverted signal can drive both pins, reducing gate count versus separate enables per channel.
Is the 74VHCT540AMX RoHS compliant and Pb-free?
Yes - the "X" suffix in 74VHCT540AMX indicates tape-and-reel packaging with Pb-free terminations per JEDEC J-STD-020B. The device meets RoHS Directive 2011/65/EU requirements, with lead content <1000 ppm and no intentionally added cadmium, hexavalent chromium, mercury, PBB, or PBDE.
74VHCT540AMX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74VHCT
- 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:
- 8mA, 8mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
74VHCT540AMX FAQ
1.How can I place an order for 74VHCT540AMX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74VHCT540AMX 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 74VHCT540AMX reliable?
The price and inventory of 74VHCT540AMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VHCT540AMX is usually 5 days.
3.What payment methods are accepted for 74VHCT540AMX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74VHCT540AMX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74VHCT540AMX?
74VHCT540AMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74VHCT540AMX 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 74VHCT540AMX?
For technical support, including 74VHCT540AMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VHCT540AMX requirements.
6.How does Aetrix verify that 74VHCT540AMX is sourced from the original manufacturer or authorized distributors?
All 74VHCT540AMX 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 74VHCT540AMX meets industry standards.
7.What is the process for return or replacement of 74VHCT540AMX?
All 74VHCT540AMX units undergo pre-shipment inspection (PSI). If there is an issue with 74VHCT540AMX, 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 74VHCT540AMX part is unused and in its original packaging.
Return procedure for 74VHCT540AMX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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