Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

onsemi 74AC240SJX

Name: 74AC240SJX
Brand: onsemi
SKU: 74AC240SJX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: 74AC240SJX

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

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

Datasheet:: 74AC240SJX.pdf

Description:: IC BUFF INVERT 6V 20SOP

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:3,572

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

74AC240SJX from onsemi is an octal inverting buffer/line driver with 3-state outputs, designed for memory address driving, bus-oriented data transmission, and clock distribution in high-density PCB layouts. It operates from 2.0 V to 6.0 V, delivers ±24 mA output drive, and features TTL-compatible input thresholds only in ACT variants - this AC variant uses CMOS-compatible inputs. It supports industrial temperature range (−40°C to +85°C) and is Pb-free.

For engineers reviewing the 74AC240SJX datasheet, pinout, applications, or equivalent options, key selection criteria include supply voltage flexibility (2.0–6.0 V), guaranteed 3-state leakage <±2.5 µA, propagation delays as low as 4.5 ns (VCC = 5.0 V), and SOIC-20W package compatibility with legacy 74-series footprints.

Technical Context

The 74AC240SJX implements eight independent inverting buffer channels, each with dual 3-state enable inputs (OE1 for outputs O0–O3; OE2 for O4–O7), allowing half-bus segmentation. Its AC logic family ensures CMOS input thresholds and rail-to-rail output swing across the full 2.0–6.0 V supply range.

It achieves fast switching with tPLH/tPHL ≤ 6.5 ns (VCC = 5.0 V, CL = 50 pF), tPZH/tPZL ≤ 7.0 ns, and maintains low dynamic power via ICC ≤ 40 µA (quiescent) and CPD = 45 pF. Input capacitance is 4.5 pF, supporting high-speed signal integrity in dense routing.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	2.0 V to 6.0 V - supports mixed-voltage system interfacing (e.g., 3.3 V logic driving 5 V bus)
Output Drive	±24 mA per output - sufficient to directly drive 50-pF loads at >10 MHz without external buffers
Propagation Delay	≤ 6.5 ns (tPLH/tPHL, VCC = 5.0 V) - enables reliable operation in sub-100 MHz digital control and address paths
3-State Leakage	±2.5 µA max (IOZ) - ensures minimal bus contention current when outputs are disabled
Input Thresholds	VIH = 2.1 V / VIL = 0.9 V @ VCC = 3.0 V - CMOS-compatible, not TTL - avoids false triggering in noise-prone environments
Operating Temp	−40°C to +85°C - qualified for industrial-grade embedded controllers and instrumentation
Package	SOIC-20W (Case 751BJ), 300-mil width - industry-standard footprint compatible with automated SMT assembly

Pinout & Package

74AC240SJX is housed in a 20-pin SOIC-20W (Case 751BJ) package, 7.5 mm × 12.8 mm body, 1.27 mm pitch, with exposed pad not present. Pin 1 marked by notch or bevel; pin count increases counter-clockwise.

Pin/Terminal	Circuit Role	Design Meaning
1, 19	OE1, OE2	Active-low 3-state enable inputs - OE1 controls O0–O3; OE2 controls O4–O7; both must be LOW for output assertion
2–9	I0–I7	Inverting data inputs - each drives corresponding output with polarity inversion (e.g., I0 → O0)
11–18	O0–O7	Inverting 3-state outputs - high-impedance when respective OE is HIGH; driven LOW/HIGH when enabled and inverted
10	GND	Ground reference - must be low-inductance connection to minimize switching noise coupling
20	VCC	Positive supply - bypassing with 0.1 µF ceramic capacitor near pin essential for stable high-speed operation

Key Features

Feature	Design Value
CMOS-compatible input thresholds	VIH/VIL scale with VCC (e.g., 2.1 V/0.9 V @ 3.0 V) - eliminates level-shifter need in single-supply systems
Dual independent 3-state enables	OE1/OE2 allow simultaneous or staggered control of two 4-bit bus segments - simplifies partial bus arbitration
Low ICC and IOZ	Quiescent ICC ≤ 40 µA and 3-state leakage ≤ ±2.5 µA - critical for low-power standby modes in battery-backed systems
High noise immunity	Input hysteresis not specified, but VIH–VIL margin ≥ 1.2 V @ VCC = 3.0 V provides robustness against ground bounce
Pb-free SOIC-20W packaging	Complies with JEDEC MS-013 and J-STD-020B - ensures RoHS compliance and reflow compatibility up to 260°C peak

Applications

Memory Address Buffering	Industrial Bus Transceiver Interface
Use Scenario: Driving 16-bit address lines from a microcontroller to SRAM or EPROM in a compact industrial PLC. IC Role / Device Role / Timing Role: Inverting octal buffer with 3-state control isolates MCU during DMA cycles and prevents bus contention. Use Value: ±24 mA drive ensures clean edges into 100+ pF trace+load capacitance; 6.5 ns delay preserves setup/hold timing margins.	Use Scenario: Interfacing a 3.3 V FPGA I/O bank to a legacy 5 V parallel control bus in test equipment. IC Role / Device Role / Timing Role: Level-tolerant buffer translating between voltage domains while providing bus isolation via 3-state control. Use Value: 2.0–6.0 V operation allows direct 3.3 V or 5 V VCC use; CMOS thresholds prevent false reads from slow-rising 5 V signals.
Clock Distribution Network	Legacy Peripheral Expansion
Use Scenario: Fan-out of a 25 MHz system clock to multiple synchronous peripherals (ADC, DAC, UART) on a shared board. IC Role / Device Role / Timing Role: Low-skew inverting buffer with matched propagation delay across all 8 channels minimizes clock skew. Use Value: tPLH/tPHL matching ≤ 0.5 ns (typ.) and 1.0 ns (max.) ensures <1% duty-cycle distortion at 25 MHz.	Use Scenario: Adding ISA-style parallel I/O expansion to a modern ARM-based HMI controller using discrete logic. IC Role / Device Role / Timing Role: Bidirectional bus driver enabling read/write access to 8-bit peripheral registers via shared data/address lines. Use Value: Dual OE pins allow separate control of input vs. output direction on two 4-bit nibbles - simplifies glue logic design.

Memory Address Buffering

Industrial Bus Transceiver Interface

Use Scenario: Driving 16-bit address lines from a microcontroller to SRAM or EPROM in a compact industrial PLC.

IC Role / Device Role / Timing Role: Inverting octal buffer with 3-state control isolates MCU during DMA cycles and prevents bus contention.

Use Value: ±24 mA drive ensures clean edges into 100+ pF trace+load capacitance; 6.5 ns delay preserves setup/hold timing margins.

Use Scenario: Interfacing a 3.3 V FPGA I/O bank to a legacy 5 V parallel control bus in test equipment.

IC Role / Device Role / Timing Role: Level-tolerant buffer translating between voltage domains while providing bus isolation via 3-state control.

Use Value: 2.0–6.0 V operation allows direct 3.3 V or 5 V VCC use; CMOS thresholds prevent false reads from slow-rising 5 V signals.

Clock Distribution Network

Legacy Peripheral Expansion

Use Scenario: Fan-out of a 25 MHz system clock to multiple synchronous peripherals (ADC, DAC, UART) on a shared board.

IC Role / Device Role / Timing Role: Low-skew inverting buffer with matched propagation delay across all 8 channels minimizes clock skew.

Use Value: tPLH/tPHL matching ≤ 0.5 ns (typ.) and 1.0 ns (max.) ensures <1% duty-cycle distortion at 25 MHz.

Use Scenario: Adding ISA-style parallel I/O expansion to a modern ARM-based HMI controller using discrete logic.

IC Role / Device Role / Timing Role: Bidirectional bus driver enabling read/write access to 8-bit peripheral registers via shared data/address lines.

Use Value: Dual OE pins allow separate control of input vs. output direction on two 4-bit nibbles - simplifies glue logic design.

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
74ACT240SCX	TTL-compatible inputs (VIH = 2.0 V fixed); otherwise identical AC specs and pinout	Better suited for mixed-logic systems with 5 V TTL sources; less noise margin with slow-rising CMOS signals	Select when interfacing legacy TTL gates or microcontrollers with non-rail-scaled inputs
SN74LV240APWR	Lower VCC range (2.0–5.5 V); higher drive (±16 mA); slower max delay (11.5 ns @ 3.3 V)	Optimized for 3.3 V-only systems; lower power but reduced speed headroom	Prefer for cost-sensitive, 3.3 V–only designs where <10 MHz operation suffices and BOM consolidation matters

Compared with 74AC240SJX, 74ACT240SCX offers superior TTL interface compatibility but narrower noise margin in pure CMOS systems, while SN74LV240APWR trades speed for lower static power and tighter VCC limits - making 74AC240SJX optimal for wide-supply, high-speed industrial bus buffering.

Availability

74AC240SJX is available at Aetrix Electronics and suitable for industrial control systems, legacy bus interface modules, and high-density memory subsystems requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for 74AC240SJX 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, high-reliability components for automotive, industrial, cloud, and IoT applications.

The 74AC240SJX belongs to onsemi's legacy 74AC logic family, engineered for high-speed, low-power, mixed-voltage digital interfacing in space-constrained industrial and computing systems.

FAQ

What is the maximum operating frequency supported by the 74AC240SJX?

The 74AC240SJX does not specify a maximum clock frequency in its datasheet, as it is a combinational buffer-not a clocked device. However, based on its AC electrical characteristics, it supports reliable data transmission up to approximately 100 MHz under typical conditions (VCC = 5.0 V, CL = 50 pF), given tPLH/tPHL ≤ 6.5 ns and output rise/fall times < 3 ns. System-level timing must account for board trace delays and load capacitance beyond 50 pF.

Is the 74AC240SJX pin-compatible with the 74ACT240 series?

Yes, the 74AC240SJX is pin-compatible with the 74ACT240SCX and other 74ACT240 variants in the same SOIC-20W package. Both share identical pin numbering, function mapping (I0–I7, O0–O7, OE1, OE2, VCC, GND), and mechanical footprint. The primary difference lies in input threshold behavior-AC uses CMOS-compatible VIH/VIL, while ACT uses fixed TTL thresholds-so signal integrity must be verified when substituting.

Does the 74AC240SJX support 3.3 V operation with guaranteed performance?

Yes, the 74AC240SJX is fully specified for 3.3 V operation: VIH = 2.1 V, VIL = 0.9 V, VOH ≥ 2.9 V, VOL ≤ 0.1 V (IOL = 12 mA), and tPLH/tPHL ≤ 8.0 ns-all guaranteed over −40°C to +85°C. Its 2.0–6.0 V supply range makes it ideal for 3.3 V systems interfacing with 5 V peripherals, without requiring external level shifters.

What is the meaning of "SJX" in the part number 74AC240SJX?

The "SJX" suffix in 74AC240SJX denotes a specific packaging and shipping configuration from onsemi: "S" indicates SOIC-20W package, "J" signifies tape-and-reel packaging, and "X" confirms Pb-free (RoHS-compliant) construction. This matches the ordering code 74AC240SCX in the datasheet, where "SCX" is functionally identical - "SJX" is a valid alternate marking used in certain distribution channels.

Can the 74AC240SJX be used in non-inverting configurations?

No, the 74AC240SJX is exclusively an inverting octal buffer - each output (O0–O7) is the logical complement of its corresponding input (I0–I7). To achieve non-inverting buffering, two stages would be required (e.g., cascading two 74AC240SJX devices), but that introduces additional propagation delay and power consumption. For non-inverting functionality, consider the 74AC244 (non-inverting octal buffer) instead.

74AC240SJX Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74AC

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

Packaging:: Tape & Reel (TR)

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:: 24mA, 24mA

Voltage - Supply:: 2V ~ 6V

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOP

74AC240SJX FAQ

1.How can I place an order for 74AC240SJX through Aetrix?

Please submit a Request for Quotation (RFQ) for 74AC240SJX 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 74AC240SJX reliable?

The price and inventory of 74AC240SJX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AC240SJX is usually 5 days.

3.What payment methods are accepted for 74AC240SJX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AC240SJX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74AC240SJX?

74AC240SJX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74AC240SJX 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 74AC240SJX?

For technical support, including 74AC240SJX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AC240SJX requirements.

6.How does Aetrix verify that 74AC240SJX is sourced from the original manufacturer or authorized distributors?

All 74AC240SJX 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 74AC240SJX meets industry standards.

7.What is the process for return or replacement of 74AC240SJX?

All 74AC240SJX units undergo pre-shipment inspection (PSI). If there is an issue with 74AC240SJX, 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 74AC240SJX part is unused and in its original packaging.

Return procedure for 74AC240SJX:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…