Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

onsemi 74ACQ544SC

Name: 74ACQ544SC
Brand: onsemi
SKU: 74ACQ544SC
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: 74ACQ544SC

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 24-SOIC (0.295", 7.50mm Width)

Datasheet:: 74ACQ544SC.pdf

Description:: IC BUFF INVERT 6V 24SOP

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:3,321

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

74ACQ544 from Fairchild Semiconductor is an inverting octal registered transceiver with dual-direction 3-STATE outputs, operating across 2.0V–6.0V supply, featuring guaranteed simultaneous switching noise suppression, 8-bit latched data flow control, and ±24 mA output drive capability. It enables bidirectional buffered data transfer in bus isolation and register-based interface applications.

For engineers reviewing the 74ACQ544 datasheet, pinout, applications, or equivalent options, this device supports precise timing-critical bidirectional bus interfacing where quiet switching, latch-controlled data staging, and independent A/B enable logic are required.

Technical Context

The 74ACQ544 integrates two independent sets of eight D-type latches-one for A-to-B and one for B-to-A data paths-with separate active-low Latch Enable (LEAB/LEBA) and Output Enable (OEAB/OEBA) controls. Each direction operates transparently when its CE and LE are low, then latches on LE rising edge.

It implements Fairchild's FACT Quiet Series™ architecture with GTO™ output control and undershoot correction, plus split ground bus design to minimize dynamic threshold shift and crosstalk during simultaneous output switching-verified at up to 8 outputs toggling at 1 MHz under 50 pF load.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	2.0 V to 6.0 V - Supports mixed-voltage system interfacing (e.g., 3.3 V ↔ 5 V buses) without level shifters.
Output Drive Strength	±24 mA - Sustains robust signal integrity driving 50 pF loads with <8.5 ns propagation delay (tPLH/tPHL) at 5 V.
Simultaneous Switching Noise	VOLP ≤ 1.5 V (max) - Guaranteed quiet LOW-level output voltage excursion during worst-case 7-output switching.
Propagation Delay (A↔B)	7.5 ns (max, 5 V, CL = 50 pF) - Enables reliable operation in high-speed synchronous bus architectures up to ~100 MHz effective throughput.
Latch Setup/Hold Time	tS = 3.0 ns, tH = 1.5 ns - Allows tight timing integration with fast microcontroller or FPGA control clocks.
Input Leakage Current	±1.0 µA (max) - Ensures minimal loading on upstream drivers and stable logic levels in low-power standby modes.
Operating Temperature	−40°C to +85°C - Qualified for industrial-grade embedded systems including motor control and instrumentation interfaces.

Pinout & Package

74ACQ544SC is housed in a 24-lead SOIC package (JEDEC MS-013, 0.300" wide, Package Number M24B), with gull-wing leads and standard 1.27 mm pitch.

Pin/Terminal	Circuit Role	Design Meaning
1 (OEAB)	A-to-B Output Enable Input	Active-low control enabling/disabling B-side 3-STATE outputs; decoupled from latch state for independent output gating.
2 (CEAB)	A-to-B Enable Input	Active-low control permitting A-inputs to pass through or be latched; determines data path activation before LEAB sampling.
3 (LEAB)	A-to-B Latch Enable Input	Active-low pulse-triggered latch: LOW makes A→B path transparent; rising edge captures and holds A-data at B outputs.
4–11 (A0–A7)	A-side I/O Terminals	Bi-directional: serve as inputs during A→B flow, or 3-STATE outputs during B→A flow; inverted relative to B-side.
12 (GND)	Ground Reference	Dedicated power return for quiet switching; part of split-ground bus architecture reducing simultaneous switching noise coupling.
13–20 (B0–B7)	B-side I/O Terminals	Bi-directional: serve as inputs during B→A flow, or 3-STATE outputs during A→B flow; inverted relative to A-side.
21 (LEBA)	B-to-A Latch Enable Input	Active-low pulse-triggered latch for B→A path; functionally identical to LEAB but isolated for independent bidirectional staging.
22 (CEBA)	B-to-A Enable Input	Active-low control enabling B→A data path; allows selective activation of reverse flow without affecting A→B registers.
23 (OEBA)	B-to-A Output Enable Input	Active-low control enabling/disabling A-side 3-STATE outputs; fully independent of OEAB for asymmetric bus control.
24 (VCC)	Positive Supply	2.0–6.0 V input supporting TTL- and CMOS-compatible logic families; internal regulation not required.

Key Features

Feature	Design Value
Back-to-back D-type register pairs	Enables full-cycle data staging: incoming A-data is latched before appearing on B outputs, and vice versa-preventing race conditions in bidirectional bus arbitration.
GTO™ output control	Guarantees controlled output transition slew rates to suppress EMI and reduce ground bounce during multi-bit switching events.
Split ground bus architecture	Physically isolates digital ground paths for input and output sections, minimizing noise coupling between control logic and high-current output drivers.
Undershoot correction circuitry	Actively clamps negative voltage excursions below ground during fast turn-off, maintaining VOL integrity and preventing false triggering in downstream receivers.
Separate CE/LE/OE per direction	Allows independent configuration of data capture, storage, and output assertion-enabling complex handshaking protocols without external glue logic.

Applications

Microprocessor Bus Isolation	Industrial PLC Backplane Interface
Use Scenario: Isolating CPU address/data bus from peripheral expansion slots while maintaining timing integrity across voltage domains. IC Role / Device Role / Timing Role: Bidirectional registered transceiver providing synchronized, inverted data transfer between 5 V CPU and 3.3 V peripherals with latch-controlled handshake timing. Use Value: Eliminates need for discrete buffers and timing logic; ±24 mA drive ensures signal fidelity over 15 cm PCB traces at 100 kHz burst rates.	Use Scenario: Interfacing modular I/O cards to a central controller in programmable logic controllers with hot-swap capability. IC Role / Device Role / Timing Role: Octal registered transceiver managing bidirectional configuration and status data exchange with independent A/B enable sequencing for fault-safe card insertion/removal. Use Value: Independent OEAB/OEBA control prevents bus contention during card reconfiguration; quiet switching meets EN 61000-6-4 industrial EMC requirements.
Test Equipment Data Acquisition Interface	Legacy System Protocol Bridge
Use Scenario: Capturing parallel sensor data streams from multiple analog front-ends into a centralized digitizer with synchronized sampling windows. IC Role / Device Role / Timing Role: Latched transceiver capturing 8-bit sensor readings on LEAB edge, holding data stable during multiplexed ADC conversion cycles. Use Value: 3.0 ns setup time and 1.5 ns hold time align precisely with FPGA-based sequencers; VOLP ≤ 1.5 V prevents false triggers in high-noise lab environments.	Use Scenario: Bridging legacy parallel printer port (Centronics) signals to modern microcontroller-based print controllers with protocol translation. IC Role / Device Role / Timing Role: Inverting registered transceiver buffering and synchronizing STROBE, ACK, BUSY, and DATA lines with independent direction control for handshaking compliance. Use Value: Inversion matches standard Centronics polarity; separate CEAB/CEBA enables selective activation of data vs. control line transfers without software overhead.

Microprocessor Bus Isolation

Industrial PLC Backplane Interface

Use Scenario: Isolating CPU address/data bus from peripheral expansion slots while maintaining timing integrity across voltage domains.

IC Role / Device Role / Timing Role: Bidirectional registered transceiver providing synchronized, inverted data transfer between 5 V CPU and 3.3 V peripherals with latch-controlled handshake timing.

Use Value: Eliminates need for discrete buffers and timing logic; ±24 mA drive ensures signal fidelity over 15 cm PCB traces at 100 kHz burst rates.

Use Scenario: Interfacing modular I/O cards to a central controller in programmable logic controllers with hot-swap capability.

IC Role / Device Role / Timing Role: Octal registered transceiver managing bidirectional configuration and status data exchange with independent A/B enable sequencing for fault-safe card insertion/removal.

Use Value: Independent OEAB/OEBA control prevents bus contention during card reconfiguration; quiet switching meets EN 61000-6-4 industrial EMC requirements.

Test Equipment Data Acquisition Interface

Legacy System Protocol Bridge

Use Scenario: Capturing parallel sensor data streams from multiple analog front-ends into a centralized digitizer with synchronized sampling windows.

IC Role / Device Role / Timing Role: Latched transceiver capturing 8-bit sensor readings on LEAB edge, holding data stable during multiplexed ADC conversion cycles.

Use Value: 3.0 ns setup time and 1.5 ns hold time align precisely with FPGA-based sequencers; VOLP ≤ 1.5 V prevents false triggers in high-noise lab environments.

Use Scenario: Bridging legacy parallel printer port (Centronics) signals to modern microcontroller-based print controllers with protocol translation.

IC Role / Device Role / Timing Role: Inverting registered transceiver buffering and synchronizing STROBE, ACK, BUSY, and DATA lines with independent direction control for handshaking compliance.

Use Value: Inversion matches standard Centronics polarity; separate CEAB/CEBA enables selective activation of data vs. control line transfers without software overhead.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
74ACTQ544SC	5.0 V only supply (4.5–5.5 V); higher VIH/VIL thresholds; faster ACQ-equivalent propagation (7.5 ns max vs. 8.0 ns).	Optimized for strict 5 V TTL/CMOS systems; less suitable for mixed-voltage or battery-powered 3.3 V designs.	Select when operating exclusively at 5 V and requiring tighter noise margins (VOLV = −1.2 V) and higher dynamic input immunity (VIHD = 2.2 V).
SN74ABT544N	TI ABT family; 4.5–5.5 V supply; non-inverting logic; higher drive (±64 mA); no integrated quiet-series noise suppression.	Used in high-drive, non-inverting bus applications where noise control is managed externally via layout or ferrites.	Choose when inversion is undesirable and board-level EMI mitigation is already implemented; avoid if simultaneous switching noise must be minimized at silicon level.

Compared with 74ACTQ544SC and SN74ABT544N, the 74ACQ544 offers broader voltage flexibility (2.0–6.0 V), inherent inversion for legacy interface matching, and factory-guaranteed quiet switching performance-making it optimal for mixed-supply industrial backplanes where noise and voltage compatibility are co-constrained.

Availability

74ACQ544SC is available at Aetrix Electronics and suitable for industrial PLC backplanes, test equipment data acquisition interfaces, legacy system protocol bridges, and microprocessor bus isolation requiring stable component supply and long-term obsolescence management.

Supply support for 74ACQ544SC 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 manufacturer specializing in high-performance logic, analog, and power ICs before its acquisition by ON Semiconductor in 2016.

The 74ACQ544 belongs to Fairchild's Quiet Series™ logic family, designed specifically for noise-sensitive industrial and instrumentation applications requiring guaranteed simultaneous switching noise control and deterministic timing behavior.

FAQ

What is the supply voltage range supported by the 74ACQ544?

The 74ACQ544 supports a supply voltage range of 2.0 V to 6.0 V, making it compatible with both 3.3 V and 5 V logic systems. This wide range allows direct interfacing between mixed-voltage subsystems without external level-shifting circuitry. The 74ACQ544 maintains specified AC and DC performance-including propagation delay, noise immunity, and output drive-across this entire range, as validated in the official Fairchild datasheet DS010685.

Does the 74ACQ544 invert data in both directions?

Yes, the 74ACQ544 performs inversion on data flowing in both A-to-B and B-to-A directions. This is a fixed architectural feature confirmed in the General Description and Functional Description sections of the datasheet. When data enters A0–A7, it appears inverted at B0–B7; similarly, data entering B0–B7 appears inverted at A0–A7. This behavior is intrinsic to the 74ACQ544 and cannot be disabled or bypassed.

How does the 74ACQ544 achieve quiet output switching?

The 74ACQ544 achieves quiet output switching through Fairchild's FACT Quiet Series™ technology, which includes GTO™ output control for controlled slew rates, undershoot correction circuitry to clamp negative voltage excursions, and a split ground bus to isolate input and output current paths. These features collectively guarantee VOLP ≤ 1.5 V and VOLV ≥ −1.2 V under worst-case simultaneous switching conditions, as measured per the test methodology in Figures 1 and 2 of DS010685.

What is the maximum output drive capability of the 74ACQ544?

The 74ACQ544 provides ±24 mA output drive per pin under DC conditions, verified at VCC = 5.5 V with VOH ≥ 4.76 V and VOL ≤ 0.44 V. This drive strength ensures reliable signal integrity when driving standard 50 pF loads across typical PCB trace lengths. The 74ACQ544 maintains this rating across its full operating temperature range (−40°C to +85°C), as specified in the DC Electrical Characteristics table for ACQ devices.

Can the 74ACQ544 be used as a direct replacement for the 74ACTQ544?

No-the 74ACQ544 is not a direct replacement for the 74ACTQ544 due to key electrical differences: the 74ACQ544 operates from 2.0 V to 6.0 V, while the 74ACTQ544 is limited to 4.5 V to 5.5 V. Additionally, their input threshold voltages (VIH/VIL) and dynamic noise parameters (VOLV, VIHD/VILD) differ significantly. Although both share the same pinout and logic function, substituting one for the other requires verification of supply voltage compatibility and noise margin requirements in the target application.

74ACQ544SC Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74ACQ

Package/Case:: 24-SOIC (0.295", 7.50mm Width)

Packaging:: Tube

Product Status:: Obsolete

Logic Type:: Buffer, Inverting

Number of Elements:: 1

Number of Bits per Element:: 8

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:: 24-SOP

74ACQ544SC FAQ

1.How can I place an order for 74ACQ544SC through Aetrix?

Please submit a Request for Quotation (RFQ) for 74ACQ544SC 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 74ACQ544SC reliable?

The price and inventory of 74ACQ544SC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACQ544SC is usually 5 days.

3.What payment methods are accepted for 74ACQ544SC?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACQ544SC transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74ACQ544SC?

74ACQ544SC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74ACQ544SC 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 74ACQ544SC?

For technical support, including 74ACQ544SC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACQ544SC requirements.

6.How does Aetrix verify that 74ACQ544SC is sourced from the original manufacturer or authorized distributors?

All 74ACQ544SC 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 74ACQ544SC meets industry standards.

7.What is the process for return or replacement of 74ACQ544SC?

All 74ACQ544SC units undergo pre-shipment inspection (PSI). If there is an issue with 74ACQ544SC, 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 74ACQ544SC part is unused and in its original packaging.

Return procedure for 74ACQ544SC:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…