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

onsemi 74LCX244SJ

Name: 74LCX244SJ
Brand: onsemi
SKU: 74LCX244SJ
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74LCX244SJ

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

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

Datasheet:: 74LCX244SJ.pdf

Description:: IC BUFFER NON-INVERT 3.6V 20SOP

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Product details

Overview

74LCX244SJ from ON Semiconductor (formerly Fairchild) is an octal non-inverting 3-STATE buffer/line driver designed for low-voltage bus interface in mixed-voltage systems. It operates from 2.3V to 3.6V V_CC, features 5V-tolerant inputs and outputs, delivers ±24mA drive at V_CC = 3.0V, and achieves 6.5ns max propagation delay at 3.3V - enabling use in memory address buffering, clock distribution, and 3.3V-to-5V bidirectional bus translation.

For engineers reviewing the 74LCX244SJ datasheet, pinout, applications, or equivalent options, key selection criteria include 5V tolerance without level shifters, live-insertion support, power-down high-impedance behavior, and compatibility with EIAJ TYPE II SOP-20 packaging for legacy board layouts.

Technical Context

The 74LCX244SJ implements eight independent non-inverting buffers, each controlled by one of two 3-STATE enable inputs (OE1, OE2), allowing grouped output control. Its advanced CMOS process enables high-speed operation while maintaining low ICC (≤10µA quiescent) and robust noise immunity via proprietary EMI reduction circuitry.

It supports true live insertion/withdrawal due to power-down high-impedance inputs and outputs, and meets stringent latch-up immunity (>500mA) and ESD robustness (HBM >2000V). Input and output voltage ranges extend to –0.5V to +7.0V, ensuring safe interfacing with 5V logic even when V_CC is as low as 2.3V.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CC Range	2.3V–3.6V - Enables direct operation in 2.5V/3.3V systems without regulators
Propagation Delay	6.5ns max at V_CC = 3.3V - Supports >100MHz bus timing margins
Output Drive	±24mA at V_CC = 3.0V - Drives 50Ω transmission lines or multiple TTL loads
Input/Output Tolerance	0V–5.5V - Interfaces directly with 5V peripherals without external level shifters
Quiescent ICC	10µA max - Minimizes standby power in battery-backed or always-on subsystems
Operating Temp	–40°C to +85°C - Qualified for industrial ambient environments
ESD HBM	>2000V - Reduces handling sensitivity and improves board-level reliability

Pinout & Package

74LCX244SJ is housed in a 20-lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm wide (package code M20D), with standard 1.27mm pitch and gull-wing leads compatible with reflow soldering.

Pin/Terminal	Circuit Role	Design Meaning
1, 19, 2, 20, 4, 17, 5, 16, 7, 14, 9, 12	Inputs (I0–I7) and 3-STATE Enables (OE1, OE2)	Eight data inputs plus two active-low group enables - allows selective activation of four outputs per enable
3, 5, 7, 9, 12, 14, 16, 18	Outputs (O0–O7)	Non-inverting buffered outputs with 3-STATE control - high-impedance state prevents bus contention during disable
10, 20	V_CC, GND	Single power supply pair - simplifies decoupling and layout vs. dual-rail devices

Key Features

Feature	Design Value
5V-tolerant I/O	Enables direct connection to 5V logic without external resistors or translators, reducing BOM count and signal path delay
Live insertion support	Power-down high-impedance I/O ensures safe hot-plug operation in backplane or modular systems
Low dynamic power	25pF typical power dissipation capacitance (CPD) minimizes switching current and heat generation at high frequencies
High noise immunity	Proprietary noise/EMI reduction circuitry suppresses crosstalk and ground bounce in dense PCB layouts
Latch-up immunity	Exceeds 500mA - prevents destructive latch-up under transient overvoltage or ESD events

Applications

Memory Address Buffering	Industrial PLC Backplane Interface
Use Scenario: Driving address lines from a 3.3V microcontroller to multiple 5V SRAM or EPROM devices on a shared bus. IC Role / Device Role / Timing Role: Non-inverting buffer with 3-STATE control isolates controller during bus arbitration and provides drive strength for capacitive loading. Use Value: Eliminates need for discrete level shifters while maintaining <6.5ns propagation delay for synchronous access timing.	Use Scenario: Interfacing a 3.3V FPGA I/O bank to legacy 5V I/O modules in a programmable logic controller rack. IC Role / Device Role / Timing Role: Bidirectional voltage-tolerant line driver enabling reliable communication across mixed-voltage backplane segments. Use Value: 5V-tolerant pins withstand 5V module signaling; ±24mA drive sustains signal integrity over 15cm ribbon cable runs.
Embedded Clock Distribution	Test Equipment Signal Conditioning
Use Scenario: Fan-out and impedance matching of a 3.3V system clock to multiple 5V logic analyzers or oscilloscope trigger inputs. IC Role / Device Role / Timing Role: Low-skew (<1ns) non-inverting buffer preserving edge fidelity and minimizing jitter accumulation. Use Value: 6.5ns t_PD and <1ns output skew ensure sub-nanosecond timing alignment across eight clock destinations.	Use Scenario: Conditioning digital stimulus signals from a 3.3V pattern generator before injection into 5V DUTs during functional test. IC Role / Device Role / Timing Role: Robust input protection and clean output drive prevent damage to sensitive DUT inputs and reduce false triggers. Use Value: >2000V HBM ESD rating and ±50mA absolute max output current protect both generator and DUT during repeated probe contact.

Memory Address Buffering

Industrial PLC Backplane Interface

Use Scenario: Driving address lines from a 3.3V microcontroller to multiple 5V SRAM or EPROM devices on a shared bus.

IC Role / Device Role / Timing Role: Non-inverting buffer with 3-STATE control isolates controller during bus arbitration and provides drive strength for capacitive loading.

Use Value: Eliminates need for discrete level shifters while maintaining <6.5ns propagation delay for synchronous access timing.

Use Scenario: Interfacing a 3.3V FPGA I/O bank to legacy 5V I/O modules in a programmable logic controller rack.

IC Role / Device Role / Timing Role: Bidirectional voltage-tolerant line driver enabling reliable communication across mixed-voltage backplane segments.

Use Value: 5V-tolerant pins withstand 5V module signaling; ±24mA drive sustains signal integrity over 15cm ribbon cable runs.

Embedded Clock Distribution

Test Equipment Signal Conditioning

Use Scenario: Fan-out and impedance matching of a 3.3V system clock to multiple 5V logic analyzers or oscilloscope trigger inputs.

IC Role / Device Role / Timing Role: Low-skew (<1ns) non-inverting buffer preserving edge fidelity and minimizing jitter accumulation.

Use Value: 6.5ns t_PD and <1ns output skew ensure sub-nanosecond timing alignment across eight clock destinations.

Use Scenario: Conditioning digital stimulus signals from a 3.3V pattern generator before injection into 5V DUTs during functional test.

IC Role / Device Role / Timing Role: Robust input protection and clean output drive prevent damage to sensitive DUT inputs and reduce false triggers.

Use Value: >2000V HBM ESD rating and ±50mA absolute max output current protect both generator and DUT during repeated probe contact.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
74LVC244APW	Same 20-pin TSSOP package; lower 1.65V–3.6V V_CC range; 3.5ns t_PD at 3.3V; only 5V-tolerant inputs (not outputs)	Requires external clamping or series resistors for 5V output driving; better suited for unidirectional 3.3V→5V input-only interfaces	Select when faster speed and lower V_CC minimum are critical, and output 5V tolerance is not required
SN74LVCH244A	20-pin SOIC/TSSOP; 1.65V–3.6V V_CC; 5V-tolerant inputs only; 5.5ns t_PD; higher 32mA drive at 3.3V	Lacks 5V-tolerant outputs - cannot safely drive 5V loads without external components	Choose for cost-sensitive industrial designs where full 5V I/O tolerance is unnecessary and higher drive is beneficial

Compared with 74LVC244APW and SN74LVCH244A, the 74LCX244SJ uniquely provides full 5V tolerance on both inputs and outputs within a legacy SOP-20 footprint, making it the only drop-in solution for existing 5V-bus designs requiring no layout changes or external protection.

Availability

74LCX244SJ is available at Aetrix Electronics and suitable for industrial automation, embedded instrumentation, and legacy system upgrades requiring stable component supply and long-term obsolescence management.

Supply support for 74LCX244SJ 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

ON Semiconductor (formerly Fairchild Semiconductor) is a global leader in energy-efficient semiconductor solutions, specializing in analog, power management, and logic devices for automotive, industrial, and computing markets.

The 74LCX family was developed to bridge voltage domains in mixed-signal systems, targeting high-speed, low-power 3.3V/2.5V logic interfacing with legacy 5V infrastructure - with emphasis on robustness, compatibility, and ease of migration.

FAQ

What is the maximum operating voltage for 74LCX244SJ inputs and outputs?

The 74LCX244SJ supports DC input and output voltages from –0.5V to +7.0V, with 5.5V maximum recommended for reliable 5V-tolerant operation. This allows direct connection to 5V logic families without level-shifting circuitry, provided V_CC remains within its 2.3V–3.6V range. The device's internal protection diodes and process design ensure safe operation across this extended range.

Can 74LCX244SJ be used in hot-swap applications?

Yes, the 74LCX244SJ supports live insertion/withdrawal due to its power-down high-impedance inputs and outputs. When V_CC is absent or ramping, all I/O pins enter a high-impedance state, preventing bus contention or back-driving. For guaranteed behavior during power-up, OE should be tied to V_CC via a pull-up resistor per datasheet guidance - a requirement fully satisfied in properly designed hot-swap circuits.

What is the output drive capability of 74LCX244SJ at 2.5V V_CC?

At V_CC = 2.5V, the 74LCX244SJ delivers ±8mA output current (I_OH/I_OL) per pin, as specified in the Recommended Operating Conditions table. This is sufficient to drive standard CMOS loads and short traces, though drive strength scales with V_CC - reaching ±24mA at 3.0V. Designers must verify load capacitance and trace length to maintain signal integrity at lower V_CC.

Does 74LCX244SJ require external pull-up resistors on OE pins?

Yes - to ensure defined high-impedance state during power-up or power-down, OE1 and OE2 must be tied to V_CC through external pull-up resistors. The minimum resistor value depends on the current-sourcing capability of the driving source; typical values range from 4.7kΩ to 10kΩ. Leaving OE floating violates the "unused inputs must be held HIGH or LOW" requirement and risks undefined output states.

Is 74LCX244SJ pin-compatible with other 74-series octal buffers in SOP-20 packages?

Yes - the 74LCX244SJ uses the industry-standard 20-pin SOP footprint (EIAJ TYPE II, 5.3mm wide, 1.27mm pitch) and shares identical pin assignments with 74HC244, 74HCT244, and 74LS244 in the same package variant. This enables direct replacement in legacy designs, provided voltage and timing requirements are verified - especially the 5V-tolerant I/O and 2.3V–3.6V V_CC constraint.

74LCX244SJ Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74LCX

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

Packaging:: Tube

Product Status:: Obsolete

Logic Type:: Buffer, Non-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 ~ 3.6V

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOP

74LCX244SJ FAQ

1.How can I place an order for 74LCX244SJ through Aetrix?

Please submit a Request for Quotation (RFQ) for 74LCX244SJ 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 74LCX244SJ reliable?

The price and inventory of 74LCX244SJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74LCX244SJ is usually 5 days.

3.What payment methods are accepted for 74LCX244SJ?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74LCX244SJ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74LCX244SJ?

74LCX244SJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74LCX244SJ 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 74LCX244SJ?

For technical support, including 74LCX244SJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74LCX244SJ requirements.

6.How does Aetrix verify that 74LCX244SJ is sourced from the original manufacturer or authorized distributors?

All 74LCX244SJ 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 74LCX244SJ meets industry standards.

7.What is the process for return or replacement of 74LCX244SJ?

All 74LCX244SJ units undergo pre-shipment inspection (PSI). If there is an issue with 74LCX244SJ, 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 74LCX244SJ part is unused and in its original packaging.

Return procedure for 74LCX244SJ:

1.Submit a request within 90 days.

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

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