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

onsemi 74ACQ240PC

Name: 74ACQ240PC
Brand: onsemi
SKU: 74ACQ240PC
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74ACQ240PC

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-DIP (0.300", 7.62mm)

Datasheet:: 74ACQ240PC.pdf

Description:: IC BUFF INVERT 6V 20DIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

74ACQ240PC 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 in high-density PCBs. It operates across 2.0V–6.0V supply, delivers ±24 mA output drive, guarantees ≤7.0 ns propagation delay (VCC = 5.0V, CL = 50 pF), and features Quiet Series™ technology for controlled switching noise - deployed in industrial control backplanes and legacy TTL-compatible systems.

For engineers reviewing the 74ACQ240PC datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed simultaneous switching noise performance, pin-to-pin skew control, 3-STATE enable timing (tPZL/tPLZ), dynamic input threshold immunity (VILD/VIHD), and PDIP-20 package compatibility with through-hole manufacturing workflows.

Technical Context

The 74ACQ240PC implements dual independent 3-STATE enable inputs (OE1, OE2) controlling four inverting outputs each, enabling selective bus isolation without external logic. Its Quiet Series™ architecture integrates GTO™ output control and undershoot correction to suppress ground bounce and crosstalk during high-speed transitions.

DC electrical behavior is specified over −40°C to +85°C with VCC = 2.0V–6.0V; AC performance includes guaranteed tPHL/tPLH ≤7.0 ns and output-to-output skew ≤1.0 ns at 5.0V, supporting reliable timing in synchronous bus interfaces where deterministic enable/disable latency is critical.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	2.0V to 6.0V - supports mixed-voltage system interfacing and legacy 5V TTL compatibility
Output Drive Strength	±24 mA - sufficient to drive 50-pF loads with 10 ns edge rates on standard PCB traces
Propagation Delay (tPHL/tPLH)	≤7.0 ns @ VCC = 5.0V, CL = 50 pF - enables operation in sub-100 MHz synchronous buses
3-STATE Enable Time (tPZL)	≤12.5 ns @ VCC = 3.3V - ensures fast bus arbitration response in shared-data-path systems
Simultaneous Switching Skew	≤1.0 ns - minimizes intra-device timing uncertainty during multi-bit bus toggling
Input Leakage Current	±1.0 µA max @ VCC = 5.5V - reduces static power draw and prevents unintended logic state drift
Quiet Output Noise (VOLP/VOLV)	+1.5V / −1.2V @ VCC = 5.0V - quantified dynamic noise envelope for ground-bounce-aware layout

Pinout & Package

74ACQ240PC is housed in a 20-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001 compliant, 0.300" wide, with through-hole mounting and standard 0.1" pin pitch - compatible with legacy wave-solder and manual assembly processes.

Pin/Terminal	Circuit Role	Design Meaning
1, 19	OE1, OE2	Active-Low 3-STATE enable inputs - independently disable top/bottom four outputs to partition bus segments
2–9	I0–I7	Inverting data inputs - each drives corresponding output with polarity inversion and full rail-to-rail swing
11–18	O0–O7	Inverting 3-STATE outputs - high-impedance state asserted when OE1/OE2 = HIGH; sink/source up to 24 mA
10	GND	Digital ground reference - dedicated low-inductance return path for output switching currents
20	VCC	Positive supply - must be decoupled locally with ≥0.1 µF ceramic capacitor to sustain Quiet Series™ noise suppression

Key Features

Feature	Design Value
Quiet Series™ switching noise control	Guaranteed VOLP ≤1.5V and VOLV ≥−1.2V under simultaneous switching - enables robust signal integrity without added ferrites or guard traces
Split ground bus architecture	Separates output switching current return from logic core ground - reduces internal coupling and improves dynamic threshold stability
GTO™ output control	Gradual turn-on/turn-off waveform shaping - limits di/dt-induced ground bounce and EMI in dense routing environments
Improved latch-up immunity	Withstands ±300 mA transient current injection - enhances reliability in noisy industrial environments with voltage transients
Reduced ICC and IOZ leakage	ICC ≤40 µA and IOZ ≤±2.5 µA - lowers standby power and prevents false enable in long-idle bus states

Applications

Memory Address Buffering	Legacy Bus Transceiver Interface
Use Scenario: Driving 16-bit address lines from a microcontroller to multiple SRAM chips on a single PCB layer. IC Role / Device Role / Timing Role: Inverting octal buffer isolating CPU address bus from memory load; 3-STATE enables shared bus arbitration between RAM and peripheral controllers. Use Value: Guaranteed ≤7.0 ns propagation delay and ≤1.0 ns output skew ensure setup/hold timing margins are preserved across all eight bits under worst-case voltage/temperature conditions.	Use Scenario: Interfacing a 5V ISA bus controller to TTL-level peripheral cards requiring bidirectional data buffering with direction control. IC Role / Device Role / Timing Role: Unidirectional line driver translating control signals (e.g., IOR#, IOW#) while suppressing switching noise that could corrupt adjacent data lines. Use Value: Quiet Series™ VOLP/VOLV specs and GTO™ output control reduce crosstalk-induced glitches on parallel bus lines operating at ≤8 MHz.
Industrial Clock Distribution	Backplane Signal Conditioning
Use Scenario: Distributing a 5 MHz system clock to six isolated logic modules on a DIN-rail mounted PLC backplane. IC Role / Device Role / Timing Role: Inverting clock buffer with 3-STATE enable allowing dynamic clock gating per module to reduce EMI and power consumption. Use Value: ±24 mA drive strength sustains clean square-wave edges into 50-pF distributed loads; tPZL ≤12.5 ns ensures precise clock enable timing across modules.	Use Scenario: Re-driving degraded TTL-level status signals (e.g., fault flags, ready/busy) across a 15 cm backplane with 300 mV noise margin. IC Role / Device Role / Timing Role: Signal restorer compensating for trace capacitance and series resistance; 3-STATE allows hot-swap insertion without bus contention. Use Value: VIH/VIL thresholds (2.1V/0.9V @ VCC = 3.0V) provide 1.2V noise immunity; low IOZ leakage (<±2.5 µA) prevents false triggering during idle intervals.

Memory Address Buffering

Legacy Bus Transceiver Interface

Use Scenario: Driving 16-bit address lines from a microcontroller to multiple SRAM chips on a single PCB layer.

IC Role / Device Role / Timing Role: Inverting octal buffer isolating CPU address bus from memory load; 3-STATE enables shared bus arbitration between RAM and peripheral controllers.

Use Value: Guaranteed ≤7.0 ns propagation delay and ≤1.0 ns output skew ensure setup/hold timing margins are preserved across all eight bits under worst-case voltage/temperature conditions.

Use Scenario: Interfacing a 5V ISA bus controller to TTL-level peripheral cards requiring bidirectional data buffering with direction control.

IC Role / Device Role / Timing Role: Unidirectional line driver translating control signals (e.g., IOR#, IOW#) while suppressing switching noise that could corrupt adjacent data lines.

Use Value: Quiet Series™ VOLP/VOLV specs and GTO™ output control reduce crosstalk-induced glitches on parallel bus lines operating at ≤8 MHz.

Industrial Clock Distribution

Backplane Signal Conditioning

Use Scenario: Distributing a 5 MHz system clock to six isolated logic modules on a DIN-rail mounted PLC backplane.

IC Role / Device Role / Timing Role: Inverting clock buffer with 3-STATE enable allowing dynamic clock gating per module to reduce EMI and power consumption.

Use Value: ±24 mA drive strength sustains clean square-wave edges into 50-pF distributed loads; tPZL ≤12.5 ns ensures precise clock enable timing across modules.

Use Scenario: Re-driving degraded TTL-level status signals (e.g., fault flags, ready/busy) across a 15 cm backplane with 300 mV noise margin.

IC Role / Device Role / Timing Role: Signal restorer compensating for trace capacitance and series resistance; 3-STATE allows hot-swap insertion without bus contention.

Use Value: VIH/VIL thresholds (2.1V/0.9V @ VCC = 3.0V) provide 1.2V noise immunity; low IOZ leakage (<±2.5 µA) prevents false triggering during idle intervals.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
74AC240N	No Quiet Series™ noise suppression; higher VOLP (up to 2.0V), no GTO™ or split ground bus	Lacks guaranteed simultaneous switching noise specs - requires additional layout mitigation (guard traces, local decoupling)	Select when cost sensitivity outweighs noise-criticality and board space permits added filtering components
SN74ACT240N	Narrower VCC range (4.5V–5.5V); higher VIH/VIL thresholds (2.0V/0.8V @ 5V); identical pinout and drive strength	Optimized for strict 5V-only systems; not suitable for 3.3V or mixed-supply designs where 74ACQ240PC operates	Choose only for pure 5V legacy systems requiring ACT speed grade without Quiet Series™ overhead

Compared with 74AC240N and SN74ACT240N, the 74ACQ240PC uniquely delivers verified quiet switching behavior (VOLP/VOLV), split-ground architecture, and 2.0V–6.0V operation - making it the sole option among these three for noise-sensitive, multi-voltage, or high-density PCB implementations without redesign.

Availability

74ACQ240PC is available at Aetrix Electronics and suitable for industrial control backplanes, legacy bus interface modules, and memory subsystems requiring stable component supply, long-term obsolescence management, and through-hole manufacturability.

Supply support for 74ACQ240PC 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 mixed-signal ICs, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and automotive systems.

The 74ACQ240PC belongs to the Quiet Series™ family of advanced CMOS logic devices, engineered specifically to solve simultaneous switching noise and ground bounce challenges in high-pin-count, high-speed digital backplanes and memory interfaces.

FAQ

What is the recommended operating voltage range for the 74ACQ240PC?

The 74ACQ240PC is rated for continuous operation from 2.0V to 6.0V DC supply voltage. This wide range supports interoperability with both 3.3V and 5V logic families, and accommodates supply tolerances in industrial power rails. Operation outside this range may cause functional failure or permanent damage, as confirmed by Absolute Maximum Ratings in the Fairchild datasheet DS010234.

Does the 74ACQ240PC support true bidirectional data flow?

No, the 74ACQ240PC is an inverting unidirectional octal buffer with fixed input-to-output signal direction. It does not implement internal direction control or bus transceiver logic. Data flows strictly from pins 2–9 (I0–I7) to pins 11–18 (O0–O7), with polarity inversion. For bidirectional applications, discrete directional control logic or a dedicated transceiver like the 74ACQ245 must be used alongside the 74ACQ240PC.

How does the Quiet Series™ technology in the 74ACQ240PC reduce noise?

The 74ACQ240PC incorporates Quiet Series™ features including GTO™ (Gradual Turn-On) output control, undershoot correction circuitry, and a split ground bus. These elements collectively limit di/dt during switching, suppress ground bounce, and isolate switching transients from the logic core - resulting in measured dynamic output noise (VOLP/VOLV) bounded to +1.5V/−1.2V at 5.0V, as validated in Figures 1 and 2 of DS010234.

Can the 74ACQ240PC be used in place of the standard 74AC240?

Yes, the 74ACQ240PC is pin-compatible and functionally equivalent to the 74AC240 in basic buffer operation, but adds Quiet Series™ noise suppression, improved latch-up immunity, and reduced ICC/IOZ leakage. No PCB changes are required for drop-in replacement; however, the enhanced noise performance may eliminate need for external filtering components previously used with the 74AC240.

What is the maximum capacitive load the 74ACQ240PC can drive reliably?

The 74ACQ240PC is characterized for reliable operation with up to 50 pF capacitive load per output, as specified in AC Electrical Characteristics (CL = 50 pF). At this load, propagation delay remains ≤7.0 ns and output skew ≤1.0 ns. Driving heavier loads increases delay and degrades edge fidelity; for >50 pF, output series termination or buffer fanout splitting is recommended per Fairchild application guidance in DS010234.

74ACQ240PC Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74ACQ

Package/Case:: 20-DIP (0.300", 7.62mm)

Packaging:: Tube

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:: Through Hole

Supplier Device Package:: 20-PDIP

74ACQ240PC FAQ

1.How can I place an order for 74ACQ240PC through Aetrix?

Please submit a Request for Quotation (RFQ) for 74ACQ240PC 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 74ACQ240PC reliable?

The price and inventory of 74ACQ240PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACQ240PC is usually 5 days.

3.What payment methods are accepted for 74ACQ240PC?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACQ240PC transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74ACQ240PC?

74ACQ240PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74ACQ240PC 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 74ACQ240PC?

For technical support, including 74ACQ240PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACQ240PC requirements.

6.How does Aetrix verify that 74ACQ240PC is sourced from the original manufacturer or authorized distributors?

All 74ACQ240PC 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 74ACQ240PC meets industry standards.

7.What is the process for return or replacement of 74ACQ240PC?

All 74ACQ240PC units undergo pre-shipment inspection (PSI). If there is an issue with 74ACQ240PC, 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 74ACQ240PC part is unused and in its original packaging.

Return procedure for 74ACQ240PC:

1.Submit a request within 90 days.

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

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