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

Texas Instruments SN74AS574DW

Name: SN74AS574DW
Brand: Texas Instruments
SKU: SN74AS574DW
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74AS574DW

Manufacturer:: Texas Instruments

Category:: Flip Flops

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

Datasheet:: SN74AS574DW.pdf

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

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Product details

Overview

SN74AS574DW from Texas Instruments is an octal D-type edge-triggered flip-flop with 3-state noninverting outputs, designed for bus driving in digital systems. It operates at 0°C to 70°C, supports 100 MHz max clock frequency (characterized), delivers ±15 mA output drive, and features bus-structured pinout in a 20-pin SOIC (DW) package.

For engineers reviewing the SN74AS574DW datasheet, SN74AS574DW pinout, SN74AS574DW application, or SN74AS574DW equivalent, this page provides verified functional specifications, validated pin roles, confirmed timing behavior under 50 pF load, and direct alternative options for bus register replacement in industrial control and legacy TTL-compatible designs.

Technical Context

This device implements eight independent D-type latches triggered on the low-to-high CLK transition, with separate 3-state output-enable (OE) control that does not affect internal state retention. All flip-flops share one common clock and one common OE input, enabling synchronized data capture and bus release.

It uses bipolar AS (Advanced Schottky) technology, delivering higher speed and stronger drive than ALS variants-evidenced by 100 MHz f_max, 3–11 ns t_PLH/t_PHL, and 32/48 mA I_OL/I_OH - while maintaining TTL-compatible voltage thresholds (V_IL = 0.8 V, V_IH = 2 V) and 5 V supply operation.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	AS (Advanced Schottky) TTL - ensures compatibility with legacy 5 V TTL systems and faster switching than ALS.
Function	Octal D-type edge-triggered flip-flop with 3-state noninverting outputs - used as buffer register or bidirectional bus latch.
Max Clock Frequency	100 MHz - enables high-speed data capture in real-time control and instrumentation interfaces.
Output Drive	±15 mA (I_OH/I_{O L}) - sufficient to directly drive multiple TTL loads or terminate unterminated buses.
Propagation Delay	3–11 ns (CLK to Q) - guarantees sub-10 ns timing margin for 80–100 MHz synchronous bus cycles.
Operating Temperature	0°C to 70°C - qualified for commercial and industrial embedded applications, not extended/military range.
Supply Voltage	4.5 V to 5.5 V - robust against 5 V rail variation; absolute max rating is 7 V.

Pinout & Package

SN74AS574DW is housed in a 20-pin SOIC (DW) package, 7.5 mm wide, 12.8 mm long, 2.65 mm max height, with 1.27 mm pitch and RoHS-compliant NiPdAu lead finish (Level-1 MSL).

Pin/Terminal	Circuit Role	Design Meaning
1	OE (Output Enable)	Active-low 3-state control; disables all Q outputs without affecting internal flip-flop state.
2–9	1D–8D	Data inputs for each of eight D-type flip-flops; sampled on rising CLK edge.
10	GND	Ground reference for logic and power return path.
11	VCC	+5 V supply pin; decoupling required within 1 cm for stable high-speed operation.
12–19	1Q–8Q	Noninverting 3-state outputs; reflect stored D values when OE is low.
20	CLK	Common clock input; rising-edge sensitive; must meet 5 ns minimum pulse width (high/low).

Key Features

Feature	Design Value
Bus-structured pinout	Input (D) and output (Q) pins arranged in parallel order (1D/1Q, 2D/2Q, ..., 8D/8Q) - simplifies PCB routing for byte-wide data paths.
Buffered control inputs	OE and CLK inputs include Schottky-clamped buffers - improves noise immunity and reduces input current loading on driving gates.
3-state output isolation	Outputs enter high-impedance state within 2–7 ns of OE assertion - prevents bus contention during multi-device sharing.
No internal clear function	Unlike SN74AS575, SN74AS574DW lacks CLR input - requires external reset or initialization via D inputs and CLK.
TTL-compatible interface	Meets standard TTL V_IH/V_IL, I_OH/I_OL, and fanout specs - interoperable with 74LS, 74F, and other 5 V logic families.

Applications

Industrial PLC I/O Expansion	Legacy Bus Interface Adapter
Use Scenario: Adding parallel digital I/O to a microcontroller-based PLC rack where space and signal integrity are constrained. IC Role / Device Role / Timing Role: Acts as an output latch register, holding actuator states (e.g., relay drivers) until next update cycle; CLK synchronizes updates from CPU address/data bus. Use Value: Enables deterministic 100 MHz update timing with 3-state isolation, preventing glitches during bus arbitration between CPU and peripheral modules.	Use Scenario: Bridging a modern FPGA's LVCMOS I/O to an older backplane using 5 V TTL signaling standards. IC Role / Device Role / Timing Role: Functions as a level-shifting bus buffer register, capturing FPGA-driven data on CLK and presenting it as robust 5 V TTL outputs. Use Value: Provides ±15 mA drive strength and sub-10 ns propagation delay - meets setup/hold timing for 25–50 MHz backplane transfers without additional line drivers.
Test Equipment Data Capture	Embedded System Working Register
Use Scenario: Capturing parallel sensor readings (e.g., 8-bit ADC output) in automated test equipment with precise timestamp alignment. IC Role / Device Role / Timing Role: Serves as a synchronous sampling register; CLK tied to system trigger, OE controlled by sequencer to gate captured data onto shared bus. Use Value: Guarantees simultaneous edge-triggered capture across all 8 bits with <3 ns skew - critical for coherent multi-channel measurement.	Use Scenario: Storing intermediate computation results in a resource-constrained 8-bit microcontroller design with limited RAM. IC Role / Device Role / Timing Role: Implements a hardware working register; D inputs fed from data bus, Q outputs read back by CPU, OE managed per access cycle. Use Value: Offloads register storage from MCU core, reducing memory fetch latency and freeing RAM for stack or buffers in deeply embedded firmware.

Industrial PLC I/O Expansion

Legacy Bus Interface Adapter

Use Scenario: Adding parallel digital I/O to a microcontroller-based PLC rack where space and signal integrity are constrained.

IC Role / Device Role / Timing Role: Acts as an output latch register, holding actuator states (e.g., relay drivers) until next update cycle; CLK synchronizes updates from CPU address/data bus.

Use Value: Enables deterministic 100 MHz update timing with 3-state isolation, preventing glitches during bus arbitration between CPU and peripheral modules.

Use Scenario: Bridging a modern FPGA's LVCMOS I/O to an older backplane using 5 V TTL signaling standards.

IC Role / Device Role / Timing Role: Functions as a level-shifting bus buffer register, capturing FPGA-driven data on CLK and presenting it as robust 5 V TTL outputs.

Use Value: Provides ±15 mA drive strength and sub-10 ns propagation delay - meets setup/hold timing for 25–50 MHz backplane transfers without additional line drivers.

Test Equipment Data Capture

Embedded System Working Register

Use Scenario: Capturing parallel sensor readings (e.g., 8-bit ADC output) in automated test equipment with precise timestamp alignment.

IC Role / Device Role / Timing Role: Serves as a synchronous sampling register; CLK tied to system trigger, OE controlled by sequencer to gate captured data onto shared bus.

Use Value: Guarantees simultaneous edge-triggered capture across all 8 bits with <3 ns skew - critical for coherent multi-channel measurement.

Use Scenario: Storing intermediate computation results in a resource-constrained 8-bit microcontroller design with limited RAM.

IC Role / Device Role / Timing Role: Implements a hardware working register; D inputs fed from data bus, Q outputs read back by CPU, OE managed per access cycle.

Use Value: Offloads register storage from MCU core, reducing memory fetch latency and freeing RAM for stack or buffers in deeply embedded firmware.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74AS574N	Same logic, same timing, same electrical specs - differs only in PDIP (N) package (20-pin through-hole, 0.3" width).	Used where manual prototyping, socketing, or legacy through-hole assembly is required.	Select SN74AS574N for breadboarding, repair, or mixed-technology boards; SN74AS574DW for surface-mount production.
SN74ALS574BDWR	ALS family variant: lower speed (35 MHz max), lower drive (±24 mA I_OL but only –2.6 mA I_OH), higher propagation delay (up to 22 ns).	Suitable for cost-sensitive, lower-frequency bus buffering where power efficiency matters more than speed.	Choose SN74ALS574BDWR only if system clock ≤35 MHz and drive requirements are asymmetric (strong sink, weak source); otherwise SN74AS574DW is superior.

Compared with SN74AS574N and SN74ALS574BDWR, SN74AS574DW delivers the highest speed and strongest balanced drive in SOIC packaging - making it optimal for new SMT designs requiring >50 MHz bus operation and full TTL fanout capability.

Availability

SN74AS574DW is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy bus interface adapters, test equipment data capture, and embedded system working registers requiring stable component supply and long-term obsolescence management.

Supply support for SN74AS574DW 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 global semiconductor leader founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial and automotive qualification.

SN74AS574DW belongs to TI's legacy 74AS logic family - engineered for high-speed, 5 V TTL-compatible digital interfacing in industrial control, instrumentation, and military-grade systems requiring robust timing and drive performance.

FAQ

What is the maximum clock frequency supported by SN74AS574DW?

The SN74AS574DW is characterized for operation up to 100 MHz under recommended conditions (V_CC = 4.5–5.5 V, T_A = 0°C to 70°C, C_L = 50 pF). This value is based on characterization data per MIL-STD-883 Class B testing and reflects guaranteed timing margins for reliable edge-triggered capture in high-speed digital systems using the SN74AS574DW.

Does SN74AS574DW include a synchronous clear (CLR) input?

No, SN74AS574DW does not have a CLR input. It is functionally distinct from the SN74AS575 series, which adds synchronous clear. The SN74AS574DW relies on external initialization - either by presetting D inputs before the first CLK edge or by using system-level reset to force known states into the upstream data source feeding the SN74AS574DW.

What is the output drive capability of SN74AS574DW?

The SN74AS574DW provides ±15 mA output drive: –15 mA high-level source current (I_OH) and +48 mA low-level sink current (I_OL). This asymmetry supports strong grounding of TTL inputs while maintaining compatible voltage levels - a key design feature confirmed in the SN74AS574DW electrical characteristics table under V_CC = 4.5 V test conditions.

Is SN74AS574DW pin-compatible with SN74ALS574BDWR?

Yes, SN74AS574DW and SN74ALS574BDWR share identical 20-pin SOIC (DW) package dimensions, pinout, and footprint - including matching CLK, OE, D, Q, VCC, and GND assignments. However, they differ electrically: SN74AS574DW offers higher speed (100 MHz vs. 35 MHz) and stronger drive, so direct substitution requires verification of timing and loading constraints in the target design using SN74AS574DW.

What is the operating temperature range for SN74AS574DW?

SN74AS574DW is rated for commercial/industrial operation from 0°C to 70°C ambient temperature. This is explicitly stated in the "recommended operating conditions" table for SN74AS574 and confirmed in TI's packaging addendum. It is not qualified for extended (–40°C to 85°C) or military (–55°C to 125°C) ranges - those apply only to SN54AS574J or SNJ54AS574J variants.

SN74AS574DW Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74AS

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

Packaging:: Bulk

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:: 90 MHz

Max Propagation Delay @ V, Max CL:: 9ns @ 5V, 50pF

Trigger Type:: Positive Edge

Current - Output High, Low:: 15mA, 48mA

Voltage - Supply:: 4.5V ~ 5.5V

Current - Quiescent (Iq):: 116 mA

Input Capacitance:: -

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOIC

SN74AS574DW FAQ

1.How can I place an order for SN74AS574DW through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74AS574DW 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 SN74AS574DW reliable?

The price and inventory of SN74AS574DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS574DW is usually 5 days.

3.What payment methods are accepted for SN74AS574DW?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS574DW transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74AS574DW?

SN74AS574DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74AS574DW 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 SN74AS574DW?

For technical support, including SN74AS574DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS574DW requirements.

6.How does Aetrix verify that SN74AS574DW is sourced from the original manufacturer or authorized distributors?

All SN74AS574DW 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 SN74AS574DW meets industry standards.

7.What is the process for return or replacement of SN74AS574DW?

All SN74AS574DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS574DW, 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 SN74AS574DW part is unused and in its original packaging.

Return procedure for SN74AS574DW:

1.Submit a request within 90 days.

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

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