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

onsemi 74ACT244SJX

Name: 74ACT244SJX
Brand: onsemi
SKU: 74ACT244SJX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74ACT244SJX

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

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

Datasheet:: 74ACT244SJX.pdf

Description:: IC BUFF NON-INVERT 5.5V 20SOP

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Product details

Overview

74ACT244SJX from ON Semiconductor is an octal non-inverting 3-STATE buffer/line driver designed for memory address and bus driving in 5V TTL-compatible digital systems. It features TTL-compatible inputs, ±24mA output drive capability, 5.0V nominal supply operation, and propagation delays as low as 6.5ns (typical) at VCC = 5.0V. It is commonly used in microprocessor address/data bus interfacing and peripheral I/O expansion.

For engineers reviewing the 74ACT244SJX datasheet, pinout, applications, or equivalent options, key selection criteria include 3-STATE output control timing (tPZH/tPLZ ≤ 10.5ns), DC input compatibility with TTL logic levels (VIL = 0.8V, VIH = 2.0V), and guaranteed 5.0V ±0.5V operating range with industrial temperature support (−40°C to +85°C).

Technical Context

The 74ACT244SJX implements dual independent 4-bit non-inverting buffers, each controlled by a dedicated 3-STATE enable input (OE1, OE2). Its ACT logic family ensures TTL-compatible input thresholds while delivering AC-level speed and low ICC quiescent current (≤40µA).

Each of the eight outputs can source or sink up to 24mA under defined load conditions, supporting direct connection to terminated transmission lines or high-capacitance buses. Output disable timing (tPHZ/tPLZ) and enable timing (tPZH/tPZL) are separately characterized to ensure clean bus arbitration in bidirectional data paths.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	4.5V to 5.5V - Ensures robust operation across standard 5V ±5% power rails in industrial and computing environments.
Input Voltage Thresholds	VIL = 0.8V max, VIH = 2.0V min - Guarantees reliable recognition of TTL-level signals without level-shifting circuitry.
Output Drive Strength	±24mA - Supports direct driving of 50Ω transmission lines or multiple LS-TTL loads (up to 20) without external buffers.
Propagation Delay	tPLH/tPHL = 6.5ns typ @ 5.0V - Enables use in 100+ MHz bus clock domains with sufficient timing margin.
3-STATE Enable/Disable Time	tPZH/tPZL ≤ 10.5ns, tPHZ/tPLZ ≤ 10.5ns - Minimizes bus contention during direction switching in half-duplex interfaces.
Quiescent Supply Current	ICC ≤ 40µA @ TA = −40°C to +85°C - Reduces static power in always-on control logic and battery-backed subsystems.
Operating Temperature	−40°C to +85°C - Qualified for industrial-grade embedded controllers, instrumentation, and communications equipment.

Pinout & Package

74ACT244SJX is housed in a 20-lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm wide (package code M20D), with gull-wing leads and standard JEDEC-compliant footprint.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8	Inputs I0–I7	Non-inverting data inputs for channels 0–7; accept TTL-compatible logic levels.
9, 10, 11, 12, 13, 14, 15, 16	Outputs O0–O7	Buffered, 3-STATE outputs; high-impedance when corresponding OE is inactive.
18, 19	OE1, OE2	Active-low 3-STATE enables; OE1 controls outputs O0–O3, OE2 controls O4–O7.
17	VCC	Positive supply terminal (4.5V–5.5V); decoupling capacitor required near pin.
20	GND	Ground reference for all inputs, outputs, and internal logic; low-inductance return path essential.

Key Features

Feature	Design Value
TTL-compatible inputs	Enables direct interface with legacy 5V microcontrollers, FPGAs, and peripheral ICs without level translation.
Independent dual 4-bit enables	Allows selective activation of upper/lower nibbles for partial bus gating-reducing switching noise and power surges.
Low ICC and IOZ	Quiescent current ≤40µA and 3-STATE leakage ≤2.5µA minimize standby power and prevent false bus loading.
High-speed 3-STATE control	Enable/disable times ≤10.5ns ensure glitch-free bus handoff in time-critical multiplexed address/data applications.
JEDEC-standard SOIC/SOP packaging	M20D package supports automated assembly, IPC-compliant reflow, and field-replaceable socketing in legacy designs.

Applications

Microprocessor Address Bus Driver	Peripheral I/O Expansion Interface
Use Scenario: Driving 16-bit address lines from a microcontroller to multiple memory chips on a shared PCB trace. IC Role / Device Role / Timing Role: Non-inverting buffer with 3-STATE control isolates the CPU during DMA cycles and prevents bus contention. Use Value: ±24mA drive strength maintains signal integrity over 10cm traces; fast enable/disable timing (≤10.5ns) eliminates address glitches during bus arbitration.	Use Scenario: Interfacing a microcontroller's GPIO port to multiple parallel peripherals (e.g., LCD, keypad, ADC) sharing a common data bus. IC Role / Device Role / Timing Role: Bidirectional bus transceiver emulator using independent OE1/OE2 to gate read/write directions per peripheral group. Use Value: Dual enable inputs allow simultaneous control of two 4-bit segments, enabling compact, low-pin-count peripheral multiplexing without FPGA logic.
Legacy System Bus Isolation	Industrial Control Backplane Interface
Use Scenario: Isolating a legacy ISA or VME bus segment from newer controller logic to prevent signal degradation and ground loop coupling. IC Role / Device Role / Timing Role: Unidirectional line driver providing voltage-level consistency and fanout amplification between mismatched logic families. Use Value: TTL-compatible inputs accept older bus signals directly; 5.5V absolute max rating protects against transient overvoltage on aging backplanes.	Use Scenario: Connecting PLC I/O modules to a central controller via a noise-prone 24V industrial backplane with long trace runs. IC Role / Device Role / Timing Role: Robust 3-STATE buffer stage that withstands EMI-induced input noise and provides clean, slew-controlled outputs. Use Value: −40°C to +85°C rating and 5.5V absolute max VCC ensure reliability in uncontrolled cabinet environments; low IOZ prevents false triggering during brown-out events.

Microprocessor Address Bus Driver

Peripheral I/O Expansion Interface

Use Scenario: Driving 16-bit address lines from a microcontroller to multiple memory chips on a shared PCB trace.

IC Role / Device Role / Timing Role: Non-inverting buffer with 3-STATE control isolates the CPU during DMA cycles and prevents bus contention.

Use Value: ±24mA drive strength maintains signal integrity over 10cm traces; fast enable/disable timing (≤10.5ns) eliminates address glitches during bus arbitration.

Use Scenario: Interfacing a microcontroller's GPIO port to multiple parallel peripherals (e.g., LCD, keypad, ADC) sharing a common data bus.

IC Role / Device Role / Timing Role: Bidirectional bus transceiver emulator using independent OE1/OE2 to gate read/write directions per peripheral group.

Use Value: Dual enable inputs allow simultaneous control of two 4-bit segments, enabling compact, low-pin-count peripheral multiplexing without FPGA logic.

Legacy System Bus Isolation

Industrial Control Backplane Interface

Use Scenario: Isolating a legacy ISA or VME bus segment from newer controller logic to prevent signal degradation and ground loop coupling.

IC Role / Device Role / Timing Role: Unidirectional line driver providing voltage-level consistency and fanout amplification between mismatched logic families.

Use Value: TTL-compatible inputs accept older bus signals directly; 5.5V absolute max rating protects against transient overvoltage on aging backplanes.

Use Scenario: Connecting PLC I/O modules to a central controller via a noise-prone 24V industrial backplane with long trace runs.

IC Role / Device Role / Timing Role: Robust 3-STATE buffer stage that withstands EMI-induced input noise and provides clean, slew-controlled outputs.

Use Value: −40°C to +85°C rating and 5.5V absolute max VCC ensure reliability in uncontrolled cabinet environments; low IOZ prevents false triggering during brown-out events.

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
SN74ACT244N	Same ACT logic family, identical DC/AC specs, but in PDIP (N20A) package - wider pitch, through-hole mount.	Preferred for prototyping, manual repair, or legacy through-hole PCBs; lacks SOP thermal performance and density.	Select SN74ACT244N only when board layout or serviceability requires through-hole mounting.
74LCX244MTCX	Lower-voltage (2.5V–3.6V) CMOS family; higher speed (tPD = 4.5ns typ), but incompatible TTL input thresholds (VIH = 2.0V min only at VCC = 3.0V).	Suitable for mixed-voltage 3.3V systems with level-shifted inputs; not drop-in replaceable in 5V TTL environments.	Choose 74LCX244MTCX only when migrating to 3.3V core logic and redesigning input conditioning.

Compared with SN74ACT244N and 74LCX244MTCX, the 74ACT244SJX uniquely balances 5V TTL interoperability, SOP surface-mount efficiency, and industrial temperature resilience-making it optimal for cost-sensitive, volume-manufactured 5V control boards where pin compatibility and legacy integration are critical.

Availability

74ACT244SJX is available at Aetrix Electronics and suitable for microprocessor bus interfacing, industrial I/O expansion, legacy system upgrades, and embedded controller peripheral bridging requiring stable component supply and long-term sourcing continuity.

Supply support for 74ACT244SJX 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 supplier of energy-efficient semiconductor components focused on power management, analog, logic, and sensing solutions for automotive, industrial, and cloud infrastructure markets.

The 74ACT244SJX belongs to ON Semiconductor's legacy logic portfolio, engineered for backward compatibility with 5V TTL systems while delivering improved speed, drive strength, and power efficiency over earlier 74LS and 74F families.

FAQ

What logic family does the 74ACT244SJX belong to, and how does it differ from AC or LS variants?

The 74ACT244SJX belongs to the Advanced CMOS Technology (ACT) logic family. Unlike AC variants, it features TTL-compatible input thresholds (VIH = 2.0V, VIL = 0.8V at 5V), enabling direct replacement of 74LS244 without level shifters. Compared to 74LS, it delivers faster propagation delay (6.5ns vs. 15ns), lower ICC (40µA vs. 20mA), and higher output drive (±24mA vs. ±8mA), making 74ACT244SJX ideal for upgrading legacy 5V systems with minimal redesign.

Can the 74ACT244SJX operate reliably at 3.3V supply voltage?

No, the 74ACT244SJX is not rated for 3.3V operation. Its recommended VCC range is strictly 4.5V to 5.5V, and its TTL-compatible inputs require minimum VIH = 2.0V - which falls outside safe margins at 3.3V. Attempting 3.3V operation may result in undefined logic states, excessive ICC, or premature device failure. For 3.3V systems, consider 74LCX244 or 74ALVC244 instead.

What is the function of pins 18 and 19 on the 74ACT244SJX, and how should they be driven?

Pins 18 (OE1) and 19 (OE2) are active-low 3-STATE output enable inputs. OE1 controls outputs O0–O3; OE2 controls O4–O7. Both must be pulled LOW (≤0.8V) to enable their respective outputs; HIGH (≥2.0V) places those outputs in high-impedance state. They should be driven by clean, slew-controlled logic signals - typically from a microcontroller GPIO or dedicated bus controller - and decoupled with 0.1µF capacitors near the package to suppress enable-line noise.

Does the 74ACT244SJX support hot-swap or live-insertion into a powered backplane?

No, the 74ACT244SJX is not hot-swap rated. Its absolute maximum ratings do not include undershoot/overshoot immunity during insertion, and its input structure lacks bus-hold or power-up 3-STATE protection. Applying VCC after inputs or exposing inputs to voltage before VCC stabilization risks latch-up or permanent damage. Always power-cycle the system before inserting or removing 74ACT244SJX-equipped modules.

How does the 74ACT244SJX handle capacitive bus loads exceeding 50pF?

The 74ACT244SJX AC specifications (e.g., tPLH, tPHL) are characterized at CL = 50pF. For loads >50pF, propagation delay increases linearly (~0.02ns/pF), and output rise/fall times degrade - potentially violating setup/hold windows in high-speed buses. To maintain timing integrity, limit total trace + load capacitance to ≤75pF, use series termination resistors (22–33Ω), or add one 74ACT244SJX per 4–6 loads rather than daisy-chaining beyond spec.

74ACT244SJX Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74ACT

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

Packaging:: Tape & Reel (TR)

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:: 4.5V ~ 5.5V

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOP

74ACT244SJX FAQ

1.How can I place an order for 74ACT244SJX through Aetrix?

Please submit a Request for Quotation (RFQ) for 74ACT244SJX 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 74ACT244SJX reliable?

The price and inventory of 74ACT244SJX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACT244SJX is usually 5 days.

3.What payment methods are accepted for 74ACT244SJX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACT244SJX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74ACT244SJX?

74ACT244SJX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74ACT244SJX 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 74ACT244SJX?

For technical support, including 74ACT244SJX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACT244SJX requirements.

6.How does Aetrix verify that 74ACT244SJX is sourced from the original manufacturer or authorized distributors?

All 74ACT244SJX 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 74ACT244SJX meets industry standards.

7.What is the process for return or replacement of 74ACT244SJX?

All 74ACT244SJX units undergo pre-shipment inspection (PSI). If there is an issue with 74ACT244SJX, 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 74ACT244SJX part is unused and in its original packaging.

Return procedure for 74ACT244SJX:

1.Submit a request within 90 days.

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

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