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

onsemi 74VHCT240ASJ

Name: 74VHCT240ASJ
Brand: onsemi
SKU: 74VHCT240ASJ
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74VHCT240ASJ

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-SOIC (0.209", 5.30mm Width)

Datasheet:: 74VHCT240ASJ.pdf

Description:: IC BUFFER INVERT 5.5V 20SOP

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Product details

Overview

74VHCT240ASJ from onsemi is an octal inverting 3-STATE buffer/line driver with two active-low output enables, designed for memory address driving, clock distribution, and bus-oriented transmitter/receiver applications. It operates at 4.5–5.5 V, delivers 3.6 ns typical propagation delay, supports 5 V ↔ 3 V level translation, and features ±25 mA output drive per pin.

For engineers reviewing the 74VHCT240ASJ datasheet, pinout, applications, or equivalent options, key selection criteria include its dual OE control, high-speed CMOS compatibility with TTL logic levels, tri-state noise immunity, and robust input/output protection across mismatched supply conditions.

Technical Context

The 74VHCT240ASJ implements silicon-gate CMOS technology to achieve TTL-compatible speed (t_PD = 5.6 ns max @ 5 V, CL = 15 pF) while maintaining low ICC (4 µA max). Its dual active-low OE inputs (OE1, OE2) independently control two groups of four inverting buffers (I0–I3/O0–O3 and I4–I7/O4–O7), enabling flexible bus partitioning.

Input and output pins tolerate −0.5 V to +6.5 V regardless of V_CC, allowing safe interfacing between 5 V and 3 V systems or battery-backed dual-supply configurations. Outputs enter high-impedance state when either OE is HIGH, with IOZ ≤ ±2.5 µA at V_CC = 5.5 V.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CC Range	4.5 V to 5.5 V - Ensures stable operation in standard 5 V digital systems with ±10% tolerance.
t_PD (Typ)	3.6 ns @ V_CC = 5 V - Enables reliable timing in high-speed address/data buses up to ~200 MHz.
I_OH/I_OL	±8 mA - Sufficient drive strength to fan out to ≥10 LSTTL loads without external buffering.
V_IH/V_IL	2.0 V / 0.8 V - TTL-compatible input thresholds ensure seamless integration with legacy 5 V logic families.
IOZ (Max)	±2.5 µA @ V_CC = 5.5 V - Minimizes leakage current during tri-state, critical for low-power standby modes.
ESD Rating	2000 V HBM - Provides baseline ESD robustness for handling and board-level assembly.

Pinout & Package

TSSOP20 package (4.4 mm × 6.5 mm, case 948AQ), 0.65 mm pitch, lead-free, moisture sensitivity level 1.

Pin/Terminal	Circuit Role	Design Meaning
1, 19	OE1, OE2	Active-low output enable controls first and second group of four buffers respectively.
2–5, 11–14	I0–I3, I4–I7	Inverting input terminals for eight independent data channels.
6–9, 15–18	O0–O3, O4–O7	Inverting 3-STATE outputs - high-impedance when corresponding OE is HIGH.
10	GND	Ground reference for all logic and power domains.
20	V_CC	Positive supply rail - must be decoupled locally to suppress switching noise.

Key Features

Feature	Design Value
High-speed CMOS	3.6 ns typical t_PD at 5 V - matches bipolar TTL performance without sacrificing power efficiency.
Input/output overvoltage tolerance	−0.5 V to +6.5 V - eliminates need for external clamping diodes in mixed-voltage interfaces.
Dual independent OE control	Separate enable for two 4-bit groups - enables selective bus gating without additional logic.
Pb-free TSSOP20	RoHS-compliant 20-pin thin shrink small outline package - suitable for high-density PCB layouts.

Applications

Memory Address Buffering	Clock Distribution
Use Scenario: Driving multiplexed address lines from a microcontroller to SRAM or Flash memory in embedded systems. IC Role / Device Role / Timing Role: Inverting 3-STATE buffer isolating CPU address bus from memory during read/write cycles. Use Value: Prevents bus contention via OE-controlled tri-state; 8-channel integration reduces component count vs discrete buffers.	Use Scenario: Distributing a system clock signal to multiple peripherals (e.g., ADC, UART, GPIO expanders) with matched loading. IC Role / Device Role / Timing Role: Low-skew inverting line driver ensuring synchronized clock edges across distributed loads. Use Value: Output-to-output skew ≤1.0 ns minimizes clock domain misalignment in multi-peripheral timing-critical designs.
5 V ↔ 3 V Level Translation	Bus-Oriented Transceiver
Use Scenario: Interfacing a 5 V FPGA I/O bank with a 3 V sensor interface IC in industrial monitoring hardware. IC Role / Device Role / Timing Role: Voltage-tolerant bidirectional buffer enabling safe logic-level conversion without level shifters. Use Value: Input/output pins withstand 0–5.5 V independent of V_CC, eliminating external voltage translators and reducing BOM cost.	Use Scenario: Bidirectional data bus isolation between processor and peripheral subsystems in automotive body control modules. IC Role / Device Role / Timing Role: Octal inverting transceiver with dual OE for direction control and bus arbitration. Use Value: Two independent OE pins allow dynamic segmentation of 8-bit data paths, improving fault containment and power management.

Memory Address Buffering

Clock Distribution

Use Scenario: Driving multiplexed address lines from a microcontroller to SRAM or Flash memory in embedded systems.

IC Role / Device Role / Timing Role: Inverting 3-STATE buffer isolating CPU address bus from memory during read/write cycles.

Use Value: Prevents bus contention via OE-controlled tri-state; 8-channel integration reduces component count vs discrete buffers.

Use Scenario: Distributing a system clock signal to multiple peripherals (e.g., ADC, UART, GPIO expanders) with matched loading.

IC Role / Device Role / Timing Role: Low-skew inverting line driver ensuring synchronized clock edges across distributed loads.

Use Value: Output-to-output skew ≤1.0 ns minimizes clock domain misalignment in multi-peripheral timing-critical designs.

5 V ↔ 3 V Level Translation

Bus-Oriented Transceiver

Use Scenario: Interfacing a 5 V FPGA I/O bank with a 3 V sensor interface IC in industrial monitoring hardware.

IC Role / Device Role / Timing Role: Voltage-tolerant bidirectional buffer enabling safe logic-level conversion without level shifters.

Use Value: Input/output pins withstand 0–5.5 V independent of V_CC, eliminating external voltage translators and reducing BOM cost.

Use Scenario: Bidirectional data bus isolation between processor and peripheral subsystems in automotive body control modules.

IC Role / Device Role / Timing Role: Octal inverting transceiver with dual OE for direction control and bus arbitration.

Use Value: Two independent OE pins allow dynamic segmentation of 8-bit data paths, improving fault containment and power management.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
74HCT240N	Same logic function and pinout, but in PDIP20 package; higher thermal resistance (JA = 65°C/W vs 150°C/W for TSSOP).	Suitable for prototyping or through-hole assembly; not recommended for high-density or thermally constrained PCBs.	Select when manual soldering or breadboard evaluation is required.
SN74LVC240APWR	3.3 V only (1.65–3.6 V V_CC); lower drive (±24 mA); no 5 V tolerant inputs - requires external level shifting for 5 V systems.	Optimized for modern low-voltage SoC interfaces; incompatible with direct 5 V input signals.	Select only for pure 3.3 V domains where 5 V tolerance is unnecessary.

Compared with 74HCT240N and SN74LVC240APWR, the 74VHCT240ASJ uniquely combines 5 V operation, 5 V-tolerant I/O, TSSOP20 footprint, and dual OE control - making it the preferred choice for space-constrained, mixed-voltage industrial and automotive bus interfaces requiring robustness and layout efficiency.

Availability

74VHCT240ASJ is available at Aetrix Electronics and suitable for memory address buffering, clock distribution, and 5 V ↔ 3 V level translation requiring stable component supply and long-term industrial availability.

Supply support for 74VHCT240ASJ 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, serving automotive, industrial, cloud, and IoT markets with power, analog, sensing, and logic solutions.

The VHCT logic family, including the 74VHCT240ASJ, was engineered for high-speed, low-power 5 V CMOS applications demanding TTL compatibility, robust voltage translation, and industrial-grade reliability across extended temperature ranges.

FAQ

What is the maximum operating temperature range for the 74VHCT240ASJ?

The 74VHCT240ASJ is rated for continuous operation from −40°C to +85°C. This industrial temperature range ensures reliable functionality in harsh environments such as factory automation controllers, automotive body electronics, and outdoor communication equipment where ambient temperatures fluctuate widely. The device's thermal resistance (θ_JA = 150°C/W) and low quiescent current support stable performance under these conditions without forced cooling.

Does the 74VHCT240ASJ support 5 V tolerant inputs when powered at 3.3 V?

No - the 74VHCT240ASJ requires V_CC = 4.5–5.5 V for guaranteed operation and does not support 3.3 V supply with 5 V inputs. Its input overvoltage tolerance (−0.5 V to +6.5 V) applies only when V_CC is within specification. For true 5 V-tolerant operation at 3.3 V supply, consider alternatives like the SN74LVC240A, which explicitly specifies 5 V tolerant inputs at V_CC = 3.3 V.

Can both OE pins of the 74VHCT240ASJ be tied together for single-enable operation?

Yes - OE1 and OE2 can be connected to a common control signal without adverse effects. Doing so configures all eight outputs as a unified 3-STATE group, simplifying system-level enable logic. However, this forfeits the flexibility of independent gating for two 4-bit sub-buses, a feature retained only when OE1 and OE2 are driven separately per application requirements.

What is the output drive capability of the 74VHCT240ASJ at V_CC = 5 V?

At V_CC = 5 V, the 74VHCT240ASJ delivers ±8 mA per output pin in active mode (I_OH = −8 mA, I_OL = 8 mA). This meets or exceeds standard LSTTL load requirements (I_OH = −0.4 mA, I_OL = 8 mA), enabling direct fan-out to up to 10 LSTTL inputs. Drive strength remains consistent across the full −40°C to +85°C operating range per datasheet specifications.

Is the 74VHCT240ASJ pin-compatible with the 74VHC240?

No - the 74VHCT240ASJ is not pin-compatible with the 74VHC240. While both are octal inverting buffers in TSSOP20 packages, the 74VHC240 uses a single active-high OE, whereas the 74VHCT240ASJ has two active-low OE pins (OE1, OE2) with different pin assignments (pins 1 and 19). Substituting one for the other would require PCB redesign and firmware logic changes to accommodate the distinct enable architecture and polarity.

74VHCT240ASJ Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74VHCT

Package/Case:: 20-SOIC (0.209", 5.30mm Width)

Packaging:: Tube

Product Status:: Obsolete

Logic Type:: Buffer, Inverting

Number of Elements:: 2

Number of Bits per Element:: 4

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-SOP

74VHCT240ASJ FAQ

1.How can I place an order for 74VHCT240ASJ through Aetrix?

Please submit a Request for Quotation (RFQ) for 74VHCT240ASJ 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 74VHCT240ASJ reliable?

The price and inventory of 74VHCT240ASJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VHCT240ASJ is usually 5 days.

3.What payment methods are accepted for 74VHCT240ASJ?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74VHCT240ASJ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74VHCT240ASJ?

74VHCT240ASJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74VHCT240ASJ 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 74VHCT240ASJ?

For technical support, including 74VHCT240ASJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VHCT240ASJ requirements.

6.How does Aetrix verify that 74VHCT240ASJ is sourced from the original manufacturer or authorized distributors?

All 74VHCT240ASJ 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 74VHCT240ASJ meets industry standards.

7.What is the process for return or replacement of 74VHCT240ASJ?

All 74VHCT240ASJ units undergo pre-shipment inspection (PSI). If there is an issue with 74VHCT240ASJ, 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 74VHCT240ASJ part is unused and in its original packaging.

Return procedure for 74VHCT240ASJ:

1.Submit a request within 90 days.

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

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