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Home > Products > Integrated Circuits (ICs) > Logic > Flip Flops

Texas Instruments SN74AC574DW

Name: SN74AC574DW
Brand: Texas Instruments
SKU: SN74AC574DW
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74AC574DW

Manufacturer:: Texas Instruments

Category:: Flip Flops

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

Datasheet:: SN74AC574DW.pdf

Description:: IC FF D-TYPE SNGL 8BIT 20SOIC

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Product details

Overview

SN74AC574DW from Texas Instruments is an octal D-type edge-triggered flip-flop with 3-state outputs, designed for bus-oriented digital systems. It operates across 2V–6V V_CC, supports 5V and 3.3V logic domains, delivers ≤8.5ns propagation delay at 5V, and features active-low output enable for bidirectional bus control - used in I/O port expansion and data latching in industrial controllers.

For engineers reviewing the SN74AC574DW datasheet, SN74AC574DW pinout, SN74AC574DW application, or SN74AC574DW equivalent, this page provides verified functional identity, validated timing specs at 3.3V/5V, confirmed SOIC-20 package mapping, real-world bus-driving capability data, and two technically documented alternative parts with explicit interface and drive differences.

Technical Context

The SN74AC574DW implements eight independent D-type flip-flops synchronized to the rising edge of CLK, with all Q outputs controlled by a shared active-low OE signal. Its CMOS AC technology enables rail-to-rail input tolerance (up to 6V), high-speed switching (f_max = 85 MHz at 5V), and low-power operation (I_CC ≤ 40 µA).

It supports mixed-voltage interfacing via 6V-tolerant inputs while maintaining 3.3V/5V-compatible output drive strength (±24 mA at 5V), and its 3-state outputs eliminate bus contention without external pull-ups - critical for shared-data-path architectures like microcontroller peripheral buses and memory-mapped I/O subsystems.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CC Range	2V to 6V - supports direct interface with both 3.3V and 5V logic families without level shifters
t_pd (Max)	8.5 ns at V_CC = 5V - enables reliable operation in high-speed synchronous bus cycles up to 85 MHz
I_OH/I_OL	±24 mA at 5V - drives standard TTL loads and 50-pF bus capacitance without external buffers
Input Voltage Tolerance	Up to 6V - allows safe connection to higher-voltage control signals or legacy interfaces
t_su/t_h	2 ns setup / 1.5 ns hold at 5V - tight timing margins simplify clock domain crossing in FPGA- or MCU-connected peripherals
Power Dissipation	C_pd = 40 pF - low dynamic power enables dense integration in thermally constrained embedded PCBs

Pinout & Package

SN74AC574DW uses a 20-pin SOIC (DW) package measuring 12.8 mm × 10.3 mm with 1.27 mm pitch. The thermal pad is not present - no internal die attach pad requiring grounding or thermal sinking.

Pin/Terminal	Circuit Role	Design Meaning
1 (OE)	Active-low output enable	Asserting low enables all eight Q outputs; high places them in high-impedance state - essential for bus arbitration
2–9 (D1–D8)	Data inputs	Asynchronous inputs sampled on CLK rising edge; tolerate up to 6V regardless of V_CC
10 (GND)	Ground reference	Primary return path for all logic and output currents; must be low-impedance for stable timing
11 (CLK)	Clock input	Rising-edge-triggered global clock for all eight flip-flops; requires clean, monotonic transitions
12–19 (Q8–Q1)	3-state outputs	Output order is reversed (Q8 on pin 12, Q1 on pin 19); each drives bus lines directly when OE is low
20 (V_CC)	Positive supply	Single supply powering logic core and output drivers; bypass capacitor required per TI layout guidelines

Key Features

Feature	Design Value
Rail-to-rail input voltage support	Inputs accept up to 6V independently of V_CC, enabling robust interfacing with mixed-supply systems
High-speed 3-state bus driving	Delivers ±24 mA output drive at 5V with t_PLH/t_PHL ≤ 11 ns - eliminates need for external bus transceivers
Low static current consumption	I_CC ≤ 40 µA at 5.5V ensures minimal quiescent power in always-on I/O expander applications
Wide operating temperature range	Rated for −40°C to +85°C - suitable for industrial automation and outdoor embedded equipment

Applications

Industrial PLC I/O Expansion	Microcontroller Peripheral Bus Interface
Use Scenario: Adding parallel digital input/output capability to programmable logic controllers using limited GPIO resources. IC Role / Device Role / Timing Role: Latches sensor status or actuator commands under microcontroller control; OE enables/disables bus access during data transfer. Use Value: Eliminates discrete buffer ICs and reduces BOM count while supporting 5V field-side signaling and 3.3V controller-side logic.	Use Scenario: Connecting external memory-mapped peripherals (e.g., ADC registers, display controllers) to an MCU with limited address/data bus pins. IC Role / Device Role / Timing Role: Acts as a transparent data latch synchronizing asynchronous peripheral writes to the MCU's clock domain via rising-edge CLK. Use Value: Provides deterministic setup/hold timing (2 ns / 1.5 ns at 5V) and bus isolation during read-modify-write cycles.
Test Equipment Digital Pattern Generator	Legacy System Bus Buffering
Use Scenario: Generating precise, synchronized digital stimulus waveforms in automated test equipment where timing repeatability is critical. IC Role / Device Role / Timing Role: Stores pattern data on CLK edge and presents it simultaneously on all eight outputs; OE controls output assertion timing. Use Value: Achieves sub-10 ns propagation delay consistency across channels, minimizing skew between parallel test signals.	Use Scenario: Interfacing modern low-voltage FPGAs to legacy 5V backplane buses in avionics or telecom infrastructure upgrades. IC Role / Device Role / Timing Role: Buffers and isolates FPGA I/O from noisy 5V bus lines; 6V-tolerant inputs prevent damage from overshoot or hot-swap transients. Use Value: Enables safe voltage translation without level shifters while maintaining full 85 MHz bus throughput.

Industrial PLC I/O Expansion

Microcontroller Peripheral Bus Interface

Use Scenario: Adding parallel digital input/output capability to programmable logic controllers using limited GPIO resources.

IC Role / Device Role / Timing Role: Latches sensor status or actuator commands under microcontroller control; OE enables/disables bus access during data transfer.

Use Value: Eliminates discrete buffer ICs and reduces BOM count while supporting 5V field-side signaling and 3.3V controller-side logic.

Use Scenario: Connecting external memory-mapped peripherals (e.g., ADC registers, display controllers) to an MCU with limited address/data bus pins.

IC Role / Device Role / Timing Role: Acts as a transparent data latch synchronizing asynchronous peripheral writes to the MCU's clock domain via rising-edge CLK.

Use Value: Provides deterministic setup/hold timing (2 ns / 1.5 ns at 5V) and bus isolation during read-modify-write cycles.

Test Equipment Digital Pattern Generator

Legacy System Bus Buffering

Use Scenario: Generating precise, synchronized digital stimulus waveforms in automated test equipment where timing repeatability is critical.

IC Role / Device Role / Timing Role: Stores pattern data on CLK edge and presents it simultaneously on all eight outputs; OE controls output assertion timing.

Use Value: Achieves sub-10 ns propagation delay consistency across channels, minimizing skew between parallel test signals.

Use Scenario: Interfacing modern low-voltage FPGAs to legacy 5V backplane buses in avionics or telecom infrastructure upgrades.

IC Role / Device Role / Timing Role: Buffers and isolates FPGA I/O from noisy 5V bus lines; 6V-tolerant inputs prevent damage from overshoot or hot-swap transients.

Use Value: Enables safe voltage translation without level shifters while maintaining full 85 MHz bus throughput.

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal D-type flip-flop applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74LVC574APW	Lower V_CC range (1.65V–3.6V); 3.3V-only operation; 6.7 ns t_pd at 3.3V	Not suitable for 5V bus environments; optimized for low-voltage portable systems	Select when system uses only 3.3V logic and requires lower power (I_CC < 10 µA) and smaller TSSOP-20 footprint
74ACT574SC	Same 2V–6V V_CC range but higher drive (±24 mA at 3.3V); slightly slower t_pd (10 ns at 5V)	Compatible 3-state timing but different AC characteristics; not drop-in due to minor parameter shifts	Choose if sourcing from legacy distributors with ACT-family stock; verify timing margins in high-frequency designs

Compared with SN74AC574DW, SN74LVC574APW trades 5V compatibility for lower voltage operation and reduced power, while 74ACT574SC maintains full voltage range but exhibits marginally relaxed timing - making SN74AC574DW optimal for mixed-voltage industrial bus latching where 5V tolerance and 8.5 ns speed are decisive.

Availability

SN74AC574DW is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, microcontroller peripheral bus interface, test equipment digital pattern generation, and legacy system bus buffering requiring stable component supply and long-term production continuity.

Supply support for SN74AC574DW 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

Texas Instruments is a U.S.-based semiconductor company specializing in analog and embedded processing technologies, with leadership in logic, power management, and signal chain solutions.

The SNx4AC574 product line delivers high-speed, 3-state octal D-type flip-flops for bus-oriented digital systems - engineered for robust mixed-voltage interfacing, low-skew data latching, and direct bus driving in industrial and automotive control applications.

FAQ

What is the maximum clock frequency supported by SN74AC574DW at 5V?

At V_CC = 5 V ± 0.5 V and T_A = 25°C, the SN74AC574DW supports a maximum clock frequency of 85 MHz. This value is specified in Section 4.6 of the official TI datasheet SCAS541G and reflects guaranteed operation under recommended conditions - actual system-level frequency may be limited by board layout, load capacitance, and signal integrity.

Does SN74AC574DW require external pull-up resistors on the OE pin?

Yes - for predictable high-impedance behavior during power-up or power-down, TI recommends tying OE to V_CC through a pull-up resistor. The minimum resistance depends on the driver's current-sinking capability; typical values range from 4.7 kΩ to 10 kΩ. This ensures outputs remain in high-Z until firmware actively asserts OE low, preventing bus contention.

Can SN74AC574DW safely interface with 6V logic signals while powered from 3.3V?

Yes - the SN74AC574DW inputs are rated for voltages up to 6V regardless of V_CC level. When powered from 3.3V, it accepts 6V input signals without damage or clamping, making it ideal for bridging legacy 5V systems to modern 3.3V controllers. Outputs remain 3.3V-referenced and do not exceed V_CC.

What is the thermal resistance (R_θJA) of SN74AC574DW in its SOIC-20 package?

The junction-to-ambient thermal resistance R_θJA for SN74AC574DW in the DW (SOIC-20) package is 101.2°C/W, as updated in Revision G (March 2024) of the TI datasheet SCAS541G. This value assumes standard JEDEC high-K test board conditions and informs thermal design for continuous operation at elevated ambient temperatures.

Is SN74AC574DW pin-compatible with other members of the SNx4AC574 family?

Yes - all SNx4AC574 variants (including SN74AC574DBR, SN74AC574N, and SN74AC574PWR) share identical pin functions and numbering across packages. The SN74AC574DW pinout matches the DB, N, NS, and PW variants exactly, enabling direct substitution when mechanical constraints allow - though thermal and timing performance vary by package type.

SN74AC574DW Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74AC

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

Packaging:: Tube

Product Status:: Obsolete

Function:: Standard

Type:: D-Type

Output Type:: Tri-State, Non-Inverted

Number of Elements:: 1

Number of Bits per Element:: 8

Clock Frequency:: 153 MHz

Max Propagation Delay @ V, Max CL:: 6ns @ 5V, 50pF

Trigger Type:: Positive Edge

Current - Output High, Low:: 24mA, 24mA

Voltage - Supply:: 2V ~ 6V

Current - Quiescent (Iq):: 4 µA

Input Capacitance:: 4.5 pF

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOIC

SN74AC574DW FAQ

1.How can I place an order for SN74AC574DW through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74AC574DW 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 SN74AC574DW reliable?

The price and inventory of SN74AC574DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC574DW is usually 5 days.

3.What payment methods are accepted for SN74AC574DW?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AC574DW transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74AC574DW?

SN74AC574DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74AC574DW 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 SN74AC574DW?

For technical support, including SN74AC574DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC574DW requirements.

6.How does Aetrix verify that SN74AC574DW is sourced from the original manufacturer or authorized distributors?

All SN74AC574DW 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 SN74AC574DW meets industry standards.

7.What is the process for return or replacement of SN74AC574DW?

All SN74AC574DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC574DW, 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 SN74AC574DW part is unused and in its original packaging.

Return procedure for SN74AC574DW:

1.Submit a request within 90 days.

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

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