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

onsemi 74ACQ240SCX

Name: 74ACQ240SCX
Brand: onsemi
SKU: 74ACQ240SCX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74ACQ240SCX

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

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

Datasheet:: 74ACQ240SCX.pdf

Description:: IC BUFF INVERT 6V 20SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

74ACQ240SCX from Fairchild Semiconductor is an inverting octal buffer/line driver with 3-STATE outputs, designed for memory address driving, clock distribution, and bus-oriented data transmission. It operates across 2.0V–6.0V supply, delivers ±24 mA output drive, guarantees ≤7.0 ns propagation delay at 5.0V/50 pF, and features Quiet Series™ technology for controlled switching noise. Used in high-density PCBs for industrial control backplanes.

For engineers reviewing the 74ACQ240SCX datasheet, pinout, applications, or equivalent options, this page provides verified functional identity, SOIC-20 package mapping, ACQ-series voltage/temperature operating limits, dynamic noise performance (VOLP/VOLV), and pin-compatible alternatives for legacy TTL-to-AC logic upgrades.

Technical Context

The 74ACQ240SCX implements dual 4-bit inverting buffers with independent 3-STATE enable controls (OE1/OE2, pins 12/14/16/18 and 3/5/7/9), supporting bus isolation and bidirectional data flow management. Its Quiet Series™ architecture integrates GTO™ output control and undershoot correction with a split ground bus to suppress simultaneous switching noise.

It guarantees pin-to-pin skew ≤1.0 ns (tOSLH/tOSHL) and dynamic input thresholds (VIHD/VILD) validated under 1 MHz switching with 3 ns edge rates. DC electrical specs are fully specified over −40°C to +85°C at VCC = 2.0–6.0V, with I_CC ≤40 µA and I_OZ ≤±2.5 µA in 3-STATE mode.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	2.0V to 6.0V - supports mixed-voltage system interfacing and 3.3V/5V bus translation without level shifters
Output Drive Strength	±24 mA - sufficient to directly drive 50-pF loads with <7 ns propagation delay, eliminating need for external buffers
Propagation Delay (tPLH/tPHL)	≤7.0 ns @ 5.0V/50 pF - enables reliable operation in 100+ MHz address/data bus timing windows
3-STATE Enable/Disable Time	tPZL ≤12.5 ns, tPLZ ≤14.0 ns @ 3.3V - ensures clean bus arbitration with minimal contention window
Simultaneous Switching Noise	VOLP ≤1.5 V, VOLV ≥−1.2 V @ 5.0V - quantified quiet-output dynamic noise margin for EMI-sensitive applications
Input Threshold Stability	VIHD ≥2.1 V, VILD ≤0.9 V @ 3.0V - guaranteed noise-immune logic recognition under fast-edge, high-noise PCB conditions
Quiescent Supply Current	I_CC ≤40 µA - enables low-power standby modes in battery-backed or energy-constrained systems

Pinout & Package

74ACQ240SCX is packaged in a 20-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" wide (Package Number M20B), with standard pin pitch of 0.050" and body width of 7.5 mm.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 4, 6, 8, 10, 13, 15	Inverting Input (I0–I7)	Accepts TTL/CMOS-level signals; inverted logic passed to corresponding output when enabled
3, 5, 7, 9	OE2 Group Enable Inputs	Active-Low control for outputs O0–O3; enables/disables four outputs simultaneously
12, 14, 16, 18	OE1 Group Enable Inputs	Active-Low control for outputs O4–O7; independent gating from OE2 group for flexible bus partitioning
11, 19	GND	Dedicated ground terminals - split ground bus reduces common-mode noise coupling between groups
20	VCC	Power supply input - decoupling required within 10 mm due to high-speed switching current demands
17, 16, 15, 14, 13, 12, 11, 10	Inverting Outputs (O7–O0)	3-STATE capable; sink/source up to 24 mA; VOL ≤0.44 V @ 24 mA ensures robust LOW-level integrity

Key Features

Feature	Design Value
Quiet Series™ Output Control	GTO™-enabled slew-rate limiting and undershoot correction reduce dynamic ground bounce by >50% vs. standard ACT240
Split Ground Bus Architecture	Separate GND paths for OE1/OE2 groups minimize crosstalk during simultaneous enable/disable transitions
Guaranteed Pin-to-Pin Skew	≤1.0 ns max skew between any two outputs - critical for synchronous bus timing integrity in multi-drop systems
Enhanced Latch-Up Immunity	Rated to ±300 mA latch-up current - withstands transient overvoltage events on I/O lines without destructive failure
Low 3-STATE Leakage	I_OZ ≤±2.5 µA - prevents signal corruption on shared buses during device disable, even at temperature extremes

Applications

Memory Address Buffering	Industrial Backplane Interface
Use Scenario: Driving 16-bit address bus in microcontroller-based PLC modules with 20 cm trace lengths and multiple load devices. IC Role / Device Role / Timing Role: Inverting buffer isolating CPU address lines from noisy peripheral bus segments while maintaining setup/hold timing margins. Use Value: ≤7.0 ns propagation delay and ≤1.0 ns output skew ensure address validity across all 8 bits within a single clock cycle at 20 MHz operation.	Use Scenario: Interfacing FPGA I/O banks to legacy 5V parallel control buses in factory automation cabinets. IC Role / Device Role / Timing Role: Level-translating and bus-driving interface with independent OE1/OE2 control for segmented bus arbitration. Use Value: 2.0–6.0V supply range and ±24 mA drive allow direct connection to both 3.3V FPGA outputs and 5V TTL peripherals without external resistors.
Programmable Logic Clock Distribution	Test Equipment Signal Conditioning
Use Scenario: Distributing synchronized clock signals from a master oscillator to eight CPLD configuration inputs on a high-density test fixture PCB. IC Role / Device Role / Timing Role: Low-skew inverting buffer ensuring deterministic clock arrival across all destinations for JTAG/SVF timing compliance. Use Value: Guaranteed tOSLH ≤1.0 ns eliminates clock skew-induced setup violations in boundary-scan chains with >100 ns period clocks.	Use Scenario: Conditioning digital stimulus signals in automated test equipment where simultaneous switching noise must not corrupt adjacent analog measurement channels. IC Role / Device Role / Timing Role: Quiet Series™-enabled buffer suppressing ground bounce during high-frequency pattern generation. Use Value: VOLP ≤1.5 V and VOLV ≥−1.2 V measured under worst-case simultaneous switching validate noise floor compatibility with 12-bit ADC reference domains.

Memory Address Buffering

Industrial Backplane Interface

Use Scenario: Driving 16-bit address bus in microcontroller-based PLC modules with 20 cm trace lengths and multiple load devices.

IC Role / Device Role / Timing Role: Inverting buffer isolating CPU address lines from noisy peripheral bus segments while maintaining setup/hold timing margins.

Use Value: ≤7.0 ns propagation delay and ≤1.0 ns output skew ensure address validity across all 8 bits within a single clock cycle at 20 MHz operation.

Use Scenario: Interfacing FPGA I/O banks to legacy 5V parallel control buses in factory automation cabinets.

IC Role / Device Role / Timing Role: Level-translating and bus-driving interface with independent OE1/OE2 control for segmented bus arbitration.

Use Value: 2.0–6.0V supply range and ±24 mA drive allow direct connection to both 3.3V FPGA outputs and 5V TTL peripherals without external resistors.

Programmable Logic Clock Distribution

Test Equipment Signal Conditioning

Use Scenario: Distributing synchronized clock signals from a master oscillator to eight CPLD configuration inputs on a high-density test fixture PCB.

IC Role / Device Role / Timing Role: Low-skew inverting buffer ensuring deterministic clock arrival across all destinations for JTAG/SVF timing compliance.

Use Value: Guaranteed tOSLH ≤1.0 ns eliminates clock skew-induced setup violations in boundary-scan chains with >100 ns period clocks.

Use Scenario: Conditioning digital stimulus signals in automated test equipment where simultaneous switching noise must not corrupt adjacent analog measurement channels.

IC Role / Device Role / Timing Role: Quiet Series™-enabled buffer suppressing ground bounce during high-frequency pattern generation.

Use Value: VOLP ≤1.5 V and VOLV ≥−1.2 V measured under worst-case simultaneous switching validate noise floor compatibility with 12-bit ADC reference domains.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
74AC240SCX	No Quiet Series™ features; higher simultaneous switching noise (no VOLP/VOLV spec); tPHL up to 9.5 ns @ 5V	Lacks dynamic noise suppression - unsuitable for mixed-signal boards with sensitive analog sections	Select when cost sensitivity outweighs EMI requirements and board layout allows extra decoupling/filtering
SN74ACT240N	ACT logic family (4.5–5.5V only); no split ground bus; VIH/VIL thresholds fixed at 2.0V/0.8V	Not compatible with 3.3V systems; requires strict 5V-only supply; lower noise immunity at VCC = 4.5V	Choose only for legacy 5V-only designs where pinout matches and Quiet Series™ is unnecessary

Compared with 74ACQ240SCX, the 74AC240SCX offers lower cost but sacrifices noise-controlled switching and skew performance, while SN74ACT240N restricts supply flexibility and lacks dynamic threshold validation - making 74ACQ240SCX the optimal choice for mixed-voltage, noise-critical, or timing-tight applications.

Availability

74ACQ240SCX is available at Aetrix Electronics and suitable for industrial control backplanes, programmable logic clock distribution, memory address buffering, and test equipment signal conditioning requiring stable component supply across extended temperature ranges.

Supply support for 74ACQ240SCX 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 power management, analog, and logic ICs before its acquisition by ON Semiconductor in 2016.

The 74ACQ240SCX belongs to Fairchild's Quiet Series™ AC logic family, engineered specifically for high-density digital systems where simultaneous switching noise, timing skew, and bus integrity are design-critical constraints.

FAQ

What is the recommended operating voltage range for the 74ACQ240SCX?

The 74ACQ240SCX is specified to operate reliably from 2.0V to 6.0V across the full industrial temperature range (−40°C to +85°C). This wide supply range enables direct interfacing between 3.3V and 5V logic domains without level-shifting circuitry. Operation outside this range risks violating absolute maximum ratings and may cause unpredictable behavior or permanent damage.

Does the 74ACQ240SCX support true bidirectional bus operation?

No - the 74ACQ240SCX is an inverting octal buffer with unidirectional signal flow (I0–I7 → O7–O0) and independent 3-STATE enables (OE1/OE2). It does not include internal direction control or bus transceiver logic. For bidirectional applications, discrete enable sequencing or companion transceivers like the 74ACQ245 are required.

How does the Quiet Series™ technology in the 74ACQ240SCX reduce noise compared to standard AC logic?

The 74ACQ240SCX incorporates GTO™ output control, undershoot correction, and a split ground bus - collectively reducing simultaneous switching noise by 50% versus standard ACT240. Measured parameters include VOLP ≤1.5 V and VOLV ≥−1.2 V under worst-case switching, directly validating improved dynamic threshold stability and reduced ground bounce.

What is the function of the dual OE inputs (OE1 and OE2) on the 74ACQ240SCX?

The 74ACQ240SCX features two independent active-low 3-STATE enable groups: OE1 (pins 12,14,16,18) controls outputs O4–O7, and OE2 (pins 3,5,7,9) controls outputs O0–O3. This allows segmented bus control - e.g., enabling only upper/lower byte lanes - improving signal integrity and reducing overall system noise during partial bus access.

Is the 74ACQ240SCX pin-compatible with the standard 74AC240 or 74ACT240?

Yes - the 74ACQ240SCX shares identical pinout, package (SOIC-20), and DC logic functionality with 74AC240 and 74ACT240. However, it adds Quiet Series™ enhancements including GTO™ control and split ground routing, which require no PCB changes but deliver measurable improvements in noise and skew performance.

74ACQ240SCX Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74ACQ

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

74ACQ240SCX FAQ

1.How can I place an order for 74ACQ240SCX through Aetrix?

Please submit a Request for Quotation (RFQ) for 74ACQ240SCX 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 74ACQ240SCX reliable?

The price and inventory of 74ACQ240SCX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACQ240SCX is usually 5 days.

3.What payment methods are accepted for 74ACQ240SCX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACQ240SCX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74ACQ240SCX?

74ACQ240SCX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74ACQ240SCX 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 74ACQ240SCX?

For technical support, including 74ACQ240SCX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACQ240SCX requirements.

6.How does Aetrix verify that 74ACQ240SCX is sourced from the original manufacturer or authorized distributors?

All 74ACQ240SCX 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 74ACQ240SCX meets industry standards.

7.What is the process for return or replacement of 74ACQ240SCX?

All 74ACQ240SCX units undergo pre-shipment inspection (PSI). If there is an issue with 74ACQ240SCX, 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 74ACQ240SCX part is unused and in its original packaging.

Return procedure for 74ACQ240SCX:

1.Submit a request within 90 days.

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

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