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

onsemi 74F244SCX

Name: 74F244SCX
Brand: onsemi
SKU: 74F244SCX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74F244SCX

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-SOIC (0.295", 7.50mm Width)

Datasheet:: 74F244SCX.pdf

Description:: IC BUF NON-INVERT 5.5V 20SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

74F244SCX from Fairchild Semiconductor is an octal non-inverting buffer/line driver with dual 3-STATE outputs, designed for memory address and data bus interfacing in TTL-compatible systems. It operates from 4.5V to 5.5V, sinks up to 64 mA per output, sources 12 mA, and features input clamp diodes for high-speed termination control - used in legacy PC motherboard I/O expansion and industrial backplane drivers.

For engineers reviewing the 74F244SCX datasheet, pinout, applications, or equivalent options, key selection criteria include 3-STATE enable polarity (OE1 active-low, OE2 active-high), SOIC-20 package compatibility, DC drive strength (64 mA sink), propagation delay (≤6.2 ns at 5V), and bus-hold immunity via internal clamping diodes.

Technical Context

The 74F244SCX implements two independent 4-bit non-inverting buffer sections, each controlled by separate 3-STATE enable inputs: OE1 (active-low) enables outputs O0–O3, OE2 (active-high) enables O4–O7. All outputs enter high-impedance state when respective enables are inactive.

It uses standard F-series TTL circuitry with Schottky-clamped transistors, supporting fan-out of 600 standard TTL loads on outputs and 1.0–2.667 unit loads on inputs. Input clamp diodes limit ringing during fast edge transitions, critical for reliable operation on unterminated PCB traces.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	+4.5 V to +5.5 V - ensures compatibility with standard 5V TTL logic rails and noise margin compliance.
Output Sink Current	64 mA per pin - drives heavy capacitive loads (e.g., >100 pF buses) without voltage droop.
Propagation Delay	≤6.2 ns (tPLH/tPHL, CL = 50 pF) - supports >100 MHz bus toggle rates in short-trace configurations.
Input Clamp Diode	−1.2 V (IIN = −18 mA) - suppresses overshoot/undershoot on fast-rising/falling edges, reducing EMI.
3-STATE Enable Logic	OE1 active-low, OE2 active-high - allows independent control of two 4-bit segments for flexible bus arbitration.
Power Supply Current	ICCZ = 60–90 mA (3-STATE active) - defines quiescent power draw during bus isolation.

Pinout & Package

74F244SCX is housed in a 20-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" wide (Package M20B), with 1.27 mm pitch and gull-wing leads.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8	Inputs D0–D7	Non-inverting data inputs; accept TTL-level signals (VIH ≥ 2.0 V, VIL ≤ 0.8 V).
9, 19	OE1, OE2	Independent 3-STATE enables: OE1 active-low (pins 1 & 19), OE2 active-high (pin 19 only - note dual function per datasheet logic symbol).
11, 12, 13, 14, 15, 16, 17, 18	Outputs O0–O7	Buffered non-inverting outputs; tri-state capable with <5.7 ns enable/disable timing (tPZH/tPHZ).
10	GND	Ground reference for all I/O and supply terminals.
20	VCC	+5 V supply rail; decoupling capacitor required within 1 cm for stable switching.

Key Features

Feature	Design Value
Dual independent 4-bit buffers	Enables segmented bus control: O0–O3 and O4–O7 driven by separate OE1/OE2 signals.
64 mA output sink capability	Drives long parallel buses or multiple TTL inputs without external buffering.
Input clamp diodes	Limit transient overvoltage on inputs during hot-plug or signal reflection events.
3-STATE output disable time ≤7.0 ns	Minimizes bus contention window during direction switching in bidirectional interfaces.

Applications

PC Memory Address Buffering	Industrial Backplane Driver
Use Scenario: Driving 20-bit address bus between CPU and SRAM/ROM in embedded controllers. IC Role / Device Role / Timing Role: Non-inverting octal buffer isolating address lines while enabling/disabling segments via OE1/OE2 for bank selection. Use Value: 64 mA sink current ensures full logic swing across 100+ mm PCB traces; 6.2 ns delay maintains setup/hold timing margins at 25 MHz clock rates.	Use Scenario: Interfacing microcontroller GPIOs to a 32-bit parallel backplane in programmable logic controllers. IC Role / Device Role / Timing Role: Level-shifting and fan-out amplification for TTL-compatible control signals routed across multi-slot chassis. Use Value: Dual OE control allows dynamic segmentation of bus segments; input clamp diodes suppress noise from relay coil switching on shared ground planes.
Legacy ISA Bus Transceiver	Test Equipment Signal Conditioning
Use Scenario: Bidirectional data buffering on Industry Standard Architecture (ISA) expansion slots. IC Role / Device Role / Timing Role: One-directional driver stage in half-duplex ISA data path, enabled by bus controller's IOR/IOW strobes mapped to OE1/OE2. Use Value: tPLZ/tPHZ ≤9.5 ns ensures clean bus release before next cycle; 5.5 V absolute max rating tolerates transient coupling from adjacent 12 V power rails.	Use Scenario: Conditioning digital stimulus signals from pattern generators before injection into DUTs. IC Role / Device Role / Timing Role: Impedance-matched line driver adding drive strength and noise immunity to low-current logic sources. Use Value: 12 mA source capability restores signal integrity after long coaxial cables; 0.55 V VOL at 64 mA guarantees robust LOW detection in noisy test environments.

PC Memory Address Buffering

Industrial Backplane Driver

Use Scenario: Driving 20-bit address bus between CPU and SRAM/ROM in embedded controllers.

IC Role / Device Role / Timing Role: Non-inverting octal buffer isolating address lines while enabling/disabling segments via OE1/OE2 for bank selection.

Use Value: 64 mA sink current ensures full logic swing across 100+ mm PCB traces; 6.2 ns delay maintains setup/hold timing margins at 25 MHz clock rates.

Use Scenario: Interfacing microcontroller GPIOs to a 32-bit parallel backplane in programmable logic controllers.

IC Role / Device Role / Timing Role: Level-shifting and fan-out amplification for TTL-compatible control signals routed across multi-slot chassis.

Use Value: Dual OE control allows dynamic segmentation of bus segments; input clamp diodes suppress noise from relay coil switching on shared ground planes.

Legacy ISA Bus Transceiver

Test Equipment Signal Conditioning

Use Scenario: Bidirectional data buffering on Industry Standard Architecture (ISA) expansion slots.

IC Role / Device Role / Timing Role: One-directional driver stage in half-duplex ISA data path, enabled by bus controller's IOR/IOW strobes mapped to OE1/OE2.

Use Value: tPLZ/tPHZ ≤9.5 ns ensures clean bus release before next cycle; 5.5 V absolute max rating tolerates transient coupling from adjacent 12 V power rails.

Use Scenario: Conditioning digital stimulus signals from pattern generators before injection into DUTs.

IC Role / Device Role / Timing Role: Impedance-matched line driver adding drive strength and noise immunity to low-current logic sources.

Use Value: 12 mA source capability restores signal integrity after long coaxial cables; 0.55 V VOL at 64 mA guarantees robust LOW detection in noisy test environments.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74F244N	PDIP-20 package; identical electrical specs; no lead finish restriction (74F244SCX is Pb-free per RoHS).	Preferred for through-hole prototyping or legacy repair; lacks SOIC thermal performance and board density.	Select SN74F244N only when manual soldering or socket-based validation is required.
74ACT244SCX	Higher speed (tPD ≤ 3.5 ns), 5V CMOS input thresholds (VIH = 3.5 V), lower ICCZ (20 µA), but reduced sink current (24 mA).	Better for mixed-voltage systems with 3.3 V control logic; unsuitable for legacy 5V TTL bus loading.	Choose 74ACT244SCX only if system uses ACT-family voltage thresholds and requires sub-4 ns timing.

Compared with SN74F244N and 74ACT244SCX, the 74F244SCX delivers optimal balance of legacy TTL compatibility, 64 mA drive, SOIC-20 footprint, and industrial temperature range support - making it the preferred choice for retrofitting or maintaining 5V bus architectures where signal integrity under load is critical.

Availability

74F244SCX is available at Aetrix Electronics and suitable for PC motherboard refurbishment, industrial backplane upgrades, and legacy test equipment maintenance requiring stable component supply and long-term obsolescence mitigation.

Supply support for 74F244SCX 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and discrete power products, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and computing infrastructure.

The 74F244SCX belongs to the 74F Fast TTL logic family, engineered for high-speed bus driving in memory, address, and clock distribution subsystems where fan-out, noise immunity, and deterministic timing were critical design constraints.

FAQ

What is the operating temperature range for the 74F244SCX?

The 74F244SCX is specified for commercial operation from 0°C to +70°C ambient temperature. Its absolute maximum junction temperature is +150°C, and it supports bias operation down to −55°C - though guaranteed AC/DC performance applies only within the 0°C to +70°C range per the datasheet's Recommended Operating Conditions table.

Does the 74F244SCX support hot-swap or live-insertion?

The 74F244SCX does not include built-in hot-swap protection. While its input clamp diodes help absorb minor transients, the device lacks power-on reset, undervoltage lockout, or current-limiting circuitry required for safe live insertion. System-level protection (e.g., series resistors, TVS diodes) must be added externally if used in hot-pluggable slots.

How are the OE1 and OE2 pins configured on the 74F244SCX?

On the 74F244SCX, OE1 (pin 1) is active-low and controls outputs O0–O3, while OE2 (pin 19) is active-high and controls outputs O4–O7. This dual-enable architecture allows independent gating of two 4-bit groups - essential for segmented bus arbitration in memory-mapped I/O designs.

Can the 74F244SCX drive a 50 pF load with full timing compliance?

Yes - the 74F244SCX AC Electrical Characteristics are explicitly tested at CL = 50 pF. Propagation delay (tPLH/tPHL) is guaranteed ≤6.2 ns and output enable/disable times (tPZH/tPHZ) ≤7.0 ns under those conditions, meeting timing budgets for 25 MHz synchronous bus operation with adequate margin.

Is the 74F244SCX RoHS-compliant and lead-free?

Yes - the "X" suffix in 74F244SCX denotes tape-and-reel packaging and confirms compliance with RoHS Directive 2011/65/EU. The SOIC package uses lead-free terminations, and the die construction meets exemption 7a (lead in high-melting-temperature type solders) where applicable per Fairchild's product change notices.

74F244SCX Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74F

Package/Case:: 20-SOIC (0.295", 7.50mm 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:: 3mA, 64mA

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOIC

74F244SCX FAQ

1.How can I place an order for 74F244SCX through Aetrix?

Please submit a Request for Quotation (RFQ) for 74F244SCX 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 74F244SCX reliable?

The price and inventory of 74F244SCX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74F244SCX is usually 5 days.

3.What payment methods are accepted for 74F244SCX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74F244SCX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74F244SCX?

74F244SCX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74F244SCX 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 74F244SCX?

For technical support, including 74F244SCX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74F244SCX requirements.

6.How does Aetrix verify that 74F244SCX is sourced from the original manufacturer or authorized distributors?

All 74F244SCX 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 74F244SCX meets industry standards.

7.What is the process for return or replacement of 74F244SCX?

All 74F244SCX units undergo pre-shipment inspection (PSI). If there is an issue with 74F244SCX, 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 74F244SCX part is unused and in its original packaging.

Return procedure for 74F244SCX:

1.Submit a request within 90 days.

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

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