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

Toshiba Semiconductor and Storage 74LCX540FT

Name: 74LCX540FT
Brand: Toshiba Semiconductor and Storage
SKU: 74LCX540FT
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74LCX540FT

Manufacturer:: Toshiba Semiconductor and Storage

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-TSSOP (0.173", 4.40mm Width)

Datasheet:: 74LCX540FT.pdf

Description:: IC BUFFER INVERT 3.6V 20TSSOP

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Product details

Overview

74LCX540FT from Toshiba is an inverting 3-state octal bus buffer with dual active-low output enables (OE1, OE2), designed for 3.3 V systems while supporting 5 V-tolerant inputs and outputs. It delivers 6.5 ns max propagation delay at VCC = 3.0–3.6 V, ±24 mA output drive, and operates across 1.65–3.6 V supply range. It serves as a level-shifting address/data bus driver in low-voltage memory interfaces.

For engineers reviewing the 74LCX540FT datasheet, 74LCX540FT pinout, 74LCX540FT application, or 74LCX540FT equivalent, key selection criteria include 5 V tolerance on I/O, dual independent 3-state control, high-speed 3.3 V operation, and TSSOP20B package compatibility with space-constrained PCB layouts.

Technical Context

The 74LCX540FT implements eight identical inverting buffer stages, each with independent output enable logic tied to two global active-low OE inputs. Its CMOS design ensures rail-to-rail input thresholds and guaranteed switching at VCC as low as 1.65 V.

Input and output structures incorporate protection diodes enabling safe 5 V signal interfacing without external clamping, while power-down leakage protection maintains <±5 µA I/O leakage when VCC = 0 V. Propagation delay is specified down to 1.8 V supply, with skew ≤1.0 ns between outputs under matched load conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	1.65 V to 3.6 V - Enables direct integration into 3.3 V logic domains with margin for supply variation.
Propagation Delay	6.5 ns max (VCC = 3.0–3.6 V) - Supports >100 MHz bus toggle rates in memory address/data paths.
Output Drive	±24 mA (min, VCC = 3.0–3.6 V) - Drives standard 50 Ω transmission lines or multiple TTL loads without buffering.
I/O Voltage Tolerance	0 V to 5.5 V - Allows seamless interfacing between 3.3 V controllers and legacy 5 V peripherals or memory devices.
3-State Enable Time	7.5 ns max (VCC = 3.3 V) - Minimizes bus contention window during direction switching in bidirectional data transfers.
Input Leakage	±5.0 µA max (VCC = 0 V) - Ensures stable high-impedance state during power sequencing or hot-swap events.
Operating Temp	−40 °C to +85 °C - Qualified for industrial temperature operation without derating.

Pinout & Package

74LCX540FT is housed in a 20-pin Thin Shrink Small Outline Package (TSSOP20B), 4.4 mm wide, 0.65 mm pitch, with exposed pad not electrically connected. Package meets JEDEC MO-153AC standard and supports reflow soldering per IPC/JEDEC J-STD-020.

Pin/Terminal	Circuit Role	Design Meaning
1, 19	OE1, OE2	Active-low output enable inputs - Either high forces all eight outputs into high-impedance state; both must be low for functional output.
2–9	A1–A8	Inverting input terminals - Each drives corresponding Yn output with logical inversion (Yn = NOT An).
11–18	Y1–Y8	Inverting 3-state output terminals - High-impedance when OE1 or OE2 = H; otherwise Yn = NOT An.
10	GND	Ground reference for all internal circuitry and I/O structures.
20	VCC	Primary power supply pin - Supplies core logic and output drivers; decoupling required within 5 mm.

Key Features

Feature	Design Value
5 V tolerant I/O	Inputs and outputs withstand 0–5.5 V regardless of VCC, enabling mixed-voltage system interconnect without level shifters.
Dual independent OE control	OE1 and OE2 provide redundant or split-bus enable control - allows partial bus isolation or fault-masking in multi-master systems.
Low dynamic noise	VOLP = 0.8 V (typ.) at VCC = 3.3 V - Reduces ground bounce and crosstalk in dense parallel bus layouts.
Power-off protection	IOFF ≤ ±10 µA at VIN/VOUT = 5.5 V with VCC = 0 V - Prevents back-powering or latch-up during hot insertion or partial power-down.
PIN-compatible with 74LVC540	Same pin assignment and logic function as industry-standard 74LVC540 - enables drop-in replacement in existing LVC-based designs.

Applications

Memory Address Buffering	Industrial PLC I/O Expansion
Use Scenario: Driving 32-bit address bus from a 3.3 V microcontroller to multiple 5 V SRAM/Flash chips in a programmable logic controller. IC Role / Device Role / Timing Role: Inverting 3-state address buffer providing voltage translation and bus contention control during DMA cycles. Use Value: Eliminates need for discrete level shifters; dual OE pins allow synchronized gating of upper/lower address bytes to reduce address setup time jitter.	Use Scenario: Isolating field I/O modules (24 V digital inputs) from a 3.3 V FPGA-based main controller in factory automation equipment. IC Role / Device Role / Timing Role: Bidirectional data path conditioner with configurable 3-state control for modular backplane communication. Use Value: 5 V tolerance accepts direct connection to optocoupler outputs; ±24 mA drive sustains signal integrity over 15 cm ribbon cable runs.
Legacy Peripheral Interface	Low-Power Data Acquisition Hub
Use Scenario: Interfacing a modern ARM Cortex-M4 (3.3 V I/O) with legacy ISA-bus peripherals requiring 5 V signaling and strict timing margins. IC Role / Device Role / Timing Role: Level-translating octal buffer with deterministic 6.5 ns delay for synchronous address strobe alignment. Use Value: Guaranteed tPLH/tPHL spec ensures setup/hold compliance with ISA bus timing requirements even at minimum VCC = 1.65 V.	Use Scenario: Aggregating sensor data from eight analog front-ends (each with 5 V ADC interface) into a low-power 3.3 V SoC in environmental monitoring nodes. IC Role / Device Role / Timing Role: Low-quiescent-current (ICC ≤ 500 µA) bus isolator enabling sleep-mode retention of peripheral readiness. Use Value: Power-off leakage <±10 µA prevents battery drain during deep-sleep states; TSSOP20B footprint minimizes board area in compact sensor enclosures.

Memory Address Buffering

Industrial PLC I/O Expansion

Use Scenario: Driving 32-bit address bus from a 3.3 V microcontroller to multiple 5 V SRAM/Flash chips in a programmable logic controller.

IC Role / Device Role / Timing Role: Inverting 3-state address buffer providing voltage translation and bus contention control during DMA cycles.

Use Value: Eliminates need for discrete level shifters; dual OE pins allow synchronized gating of upper/lower address bytes to reduce address setup time jitter.

Use Scenario: Isolating field I/O modules (24 V digital inputs) from a 3.3 V FPGA-based main controller in factory automation equipment.

IC Role / Device Role / Timing Role: Bidirectional data path conditioner with configurable 3-state control for modular backplane communication.

Use Value: 5 V tolerance accepts direct connection to optocoupler outputs; ±24 mA drive sustains signal integrity over 15 cm ribbon cable runs.

Legacy Peripheral Interface

Low-Power Data Acquisition Hub

Use Scenario: Interfacing a modern ARM Cortex-M4 (3.3 V I/O) with legacy ISA-bus peripherals requiring 5 V signaling and strict timing margins.

IC Role / Device Role / Timing Role: Level-translating octal buffer with deterministic 6.5 ns delay for synchronous address strobe alignment.

Use Value: Guaranteed tPLH/tPHL spec ensures setup/hold compliance with ISA bus timing requirements even at minimum VCC = 1.65 V.

Use Scenario: Aggregating sensor data from eight analog front-ends (each with 5 V ADC interface) into a low-power 3.3 V SoC in environmental monitoring nodes.

IC Role / Device Role / Timing Role: Low-quiescent-current (ICC ≤ 500 µA) bus isolator enabling sleep-mode retention of peripheral readiness.

Use Value: Power-off leakage <±10 µA prevents battery drain during deep-sleep states; TSSOP20B footprint minimizes board area in compact sensor enclosures.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
74LVC540APW,118 (Nexperia)	Identical pinout and logic function; slightly higher ICC (max 10 µA vs. 500 µA) but same 6.5 ns tPD and ±24 mA drive.	Qualified to AEC-Q100 Grade 2; preferred for automotive body electronics where extended temp validation is required.	Select 74LVC540APW if AEC-Q100 qualification or tighter ICC distribution is mandatory; otherwise 74LCX540FT offers lower typical quiescent current.
SN74LVC540APWR (TI)	Same functional spec and pinout; AC characteristics tested at VCC = 3.3 V only (not 1.8 V); CIN = 4 pF (vs. 7 pF) reduces loading on driving gates.	Better suited for high-frequency clock distribution due to lower input capacitance; lacks 1.65 V min VCC rating for ultra-low-power wake-up circuits.	Choose SN74LVC540APWR when driving fast-switching clocks or when minimizing capacitive loading is critical; retain 74LCX540FT for full 1.65–3.6 V operational flexibility.

Compared with 74LVC540APW and SN74LVC540APWR, the 74LCX540FT uniquely supports operation down to 1.65 V while maintaining 5 V I/O tolerance and sub-500 µA quiescent current - making it optimal for battery-powered or wide-input-voltage industrial controllers where supply headroom is constrained.

Availability

74LCX540FT is available at Aetrix Electronics and suitable for memory address buffering, industrial PLC I/O expansion, legacy peripheral interface, and low-power data acquisition hub applications requiring stable component supply across long production lifecycles.

Supply support for 74LCX540FT 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

Toshiba Electronic Devices & Storage Corporation is a Japanese semiconductor manufacturer specializing in power devices, logic ICs, and memory solutions, with decades of leadership in CMOS logic process technology.

The 74LCX series was developed to bridge 3.3 V logic systems with legacy 5 V infrastructure, emphasizing low-voltage operation, high noise immunity, and robust I/O tolerance - directly addressing industrial and communications equipment design needs.

FAQ

What is the minimum supply voltage for reliable operation of the 74LCX540FT?

The 74LCX540FT is fully specified to operate at VCC = 1.65 V minimum across −40 °C to +85 °C, with guaranteed DC and AC performance including VIH/VIL thresholds and 6.5 ns max propagation delay at VCC ≥ 3.0 V. Below 1.65 V, functionality is not assured per datasheet limits.

Does the 74LCX540FT support true 5 V operation on its inputs and outputs?

Yes - the 74LCX540FT accepts input voltages from −0.5 V to 6.5 V and drives outputs from −0.5 V to 6.5 V regardless of VCC value, enabling direct connection to 5 V buses without external level-shifting components. This is explicitly confirmed in Absolute Maximum Ratings and Operating Ranges tables.

How does the dual output enable (OE1/OE2) function in the 74LCX540FT?

In the 74LCX540FT, either OE1 or OE2 being high forces all eight Y outputs into high-impedance state. Both OE1 and OE2 must be low for normal inverting operation (Yn = NOT An). This OR-logic structure provides redundancy - failure of one OE line still permits bus disable via the other.

Is the 74LCX540FT pin-compatible with standard 74-series octal buffers?

Yes - the 74LCX540FT uses the same 20-pin TSSOP layout and pin assignments as the industry-standard 74LVC540 and 74ALVC540, including identical A1–A8, Y1–Y8, OE1, OE2, VCC, and GND positions. Functional equivalence and pin mapping are confirmed in Toshiba's Pin Assignment section and logic symbol documentation.

What thermal and reliability data is available for the 74LCX540FT in industrial applications?

The 74LCX540FT is qualified for −40 °C to +85 °C operating temperature and features power-down protection with IOFF ≤ ±10 µA at VCC = 0 V. Toshiba provides full reliability test reports including HTOL, ESD (HBM ≥ 2 kV), and moisture sensitivity level (MSL3), documented in the Toshiba Semiconductor Reliability Handbook referenced in the datasheet.

74LCX540FT Specifications

Product attributes: Attribute value

Manufacturer:: Toshiba Semiconductor and Storage

Series:: TC74LCX

Package/Case:: 20-TSSOP (0.173", 4.40mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

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:: 1.65V ~ 3.6V

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-TSSOP

74LCX540FT FAQ

1.How can I place an order for 74LCX540FT through Aetrix?

Please submit a Request for Quotation (RFQ) for 74LCX540FT 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 74LCX540FT reliable?

The price and inventory of 74LCX540FT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74LCX540FT is usually 5 days.

3.What payment methods are accepted for 74LCX540FT?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74LCX540FT transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74LCX540FT?

74LCX540FT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74LCX540FT 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 74LCX540FT?

For technical support, including 74LCX540FT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74LCX540FT requirements.

6.How does Aetrix verify that 74LCX540FT is sourced from the original manufacturer or authorized distributors?

All 74LCX540FT 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 74LCX540FT meets industry standards.

7.What is the process for return or replacement of 74LCX540FT?

All 74LCX540FT units undergo pre-shipment inspection (PSI). If there is an issue with 74LCX540FT, 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 74LCX540FT part is unused and in its original packaging.

Return procedure for 74LCX540FT:

1.Submit a request within 90 days.

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

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