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

Texas Instruments SN74S74DR

Name: SN74S74DR
Brand: Texas Instruments
SKU: SN74S74DR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74S74DR

Manufacturer:: Texas Instruments

Category:: Flip Flops

Package:: 14-SOIC (0.154", 3.90mm Width)

Datasheet:: SN74S74DR.pdf

Description:: IC FF D-TYPE DUAL 1BIT 14SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SN74S74DR from Texas Instruments is a dual D-type positive-edge-triggered flip-flop in SOIC-14 package, operating at 0°C to 70°C, with typical propagation delay of 4 ns (t_PLH/t_PHL) and output drive capability of −1 mA (I_OH) / 20 mA (I_OL). It serves as a synchronous storage element in digital logic control, clock division, and state-machine sequencing circuits.

For engineers reviewing the SN74S74DR datasheet, SN74S74DR pinout, SN74S74DR application, or SN74S74DR equivalent, this page delivers verified functional specifications, validated pin assignments, real-world use cases in TTL-compatible systems, and direct alternative options for legacy design continuity and supply chain resilience.

Technical Context

The SN74S74DR implements two independent edge-triggered D flip-flops with complementary Q and Q̅ outputs, asynchronous preset (PR̅) and clear (CLR̅) inputs active-low, and common clock (CLK) input. Each section operates on the rising edge of CLK, latching the D input state into Q on transition.

Designed for TTL-family compatibility, it features Schottky-clamped transistor-transistor logic (TTL-S) architecture, enabling higher speed and lower power-delay product than standard 74LS series. Input thresholds and output voltage levels conform to TTL electrical standards (V_IH = 2.0 V min, V_IL = 0.8 V max, V_OH = 2.7 V min at I_OH = −0.4 mA, V_OL = 0.5 V max at I_OL = 16 mA).

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	TTL-S (Schottky-clamped), ensuring 4 ns typical propagation delay and immunity to saturation-induced delays.
Supply Voltage (V_CC)	4.75 V to 5.25 V - strict 5 V ±5% tolerance required for guaranteed timing and noise margin compliance.
Propagation Delay (t_pd)	4 ns (max 8 ns) - enables reliable operation up to ~100 MHz in non-critical synchronous paths.
Output Drive (I_OL/I_OH)	20 mA sink / −1 mA source - supports direct fan-out to ≥10 standard TTL loads without buffering.
Operating Temperature	0°C to 70°C - commercial-grade rating suitable for industrial control panels and embedded instrumentation.
Package Type	SOIC-14 (D package), 3.9 mm width, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Pinout & Package

SN74S74DR uses a 14-pin Small Outline Integrated Circuit (SOIC) package (TI drawing D0014A), 3.9 mm body width, 1.75 mm max height, with gull-wing leads and pin 1 index area marked by a beveled corner or dot.

Pin/Terminal	Circuit Role	Design Meaning
1	1CLR̅	Asynchronous active-low clear for first flip-flop - forces Q1 = 0, Q̅1 = 1 independent of clock.
2	1D	Data input for first flip-flop - sampled on rising CLK edge and transferred to Q1.
3	1CLK	Clock input for first flip-flop - positive-edge sensitive; requires clean, monotonic rise time ≤ 5 ns.
4	1PR̅	Asynchronous active-low preset for first flip-flop - forces Q1 = 1, Q̅1 = 0 independent of clock.
5	1Q	True output of first flip-flop - provides registered data state synchronized to CLK.
6	1Q̅	Complementary output of first flip-flop - used for feedback, toggle configuration, or differential signaling.
7	GND	Ground reference for all internal circuitry and I/O - must be low-impedance, star-connected near device.
8	2Q̅	Complementary output of second flip-flop - electrically isolated from first section except shared V_CC/GND.
9	2Q	True output of second flip-flop - usable for independent storage or cascaded shift register stages.
10	2PR̅	Asynchronous active-low preset for second flip-flop - independent control, no cross-talk with section 1.
11	2CLK	Clock input for second flip-flop - may be tied to 1CLK for dual-register operation or driven separately.
12	2D	Data input for second flip-flop - fully independent timing domain from first section.
13	2CLR̅	Asynchronous active-low clear for second flip-flop - resets Q2 only; no effect on Q1.
14	V_CC	+5 V power supply - bypassing with 0.1 µF ceramic capacitor directly at pin is mandatory for noise suppression.

Key Features

Feature	Design Value
Dual independent D flip-flops	Enables compact implementation of 2-bit registers, dual-channel sampling, or parallel load/shift functions without external gating.
Asynchronous preset and clear per section	Allows deterministic initialization or forced reset during system startup or fault recovery, independent of clock timing.
Schottky-clamped TTL (74S) process	Delivers 2× speed improvement over 74LS while maintaining pin compatibility and board-level interoperability.
Standard SOIC-14 footprint	Direct drop-in replacement for SN74LS74ADR and SN74LS74ADBR in existing PCB layouts with no land pattern change.
Commercial temperature range (0°C to 70°C)	Validated for use in office equipment, test instruments, and consumer electronics where extended temperature is not required.

Applications

Industrial Control Logic	Digital Test Equipment
Use Scenario: Latching sensor status (e.g., limit switch closures) in PLC I/O modules before scan-cycle processing. IC Role / Device Role / Timing Role: Synchronous edge-triggered register capturing real-time binary inputs on system clock edge. Use Value: Eliminates metastability risk via controlled setup/hold timing and provides glitch-free state capture at up to 10 MHz.	Use Scenario: Generating precise, repeatable stimulus patterns in automated test fixtures for digital IC validation. IC Role / Device Role / Timing Role: Clock-divided counter stage or pattern sequencer element driving test vector generators. Use Value: 4 ns propagation delay ensures sub-10 ns timing resolution in pattern generation, critical for high-speed interface testing.
Legacy System Repair	Education & Prototyping
Use Scenario: Replacing obsolete SN74S74N in field-deployed avionics maintenance trainers requiring long-term component availability. IC Role / Device Role / Timing Role: Drop-in functional replacement preserving original timing behavior and signal integrity. Use Value: SOIC packaging enables rework onto through-hole boards using adapter sockets or hand-soldered SOIC-to-DIP carriers.	Use Scenario: Teaching sequential logic fundamentals in university labs using breadboard-based digital design experiments. IC Role / Device Role / Timing Role: Core building block for constructing counters, shift registers, and finite-state machines. Use Value: Clear pinout labeling, robust noise margins, and predictable edge-triggered behavior simplify student debugging and verification.

Industrial Control Logic

Digital Test Equipment

Use Scenario: Latching sensor status (e.g., limit switch closures) in PLC I/O modules before scan-cycle processing.

IC Role / Device Role / Timing Role: Synchronous edge-triggered register capturing real-time binary inputs on system clock edge.

Use Value: Eliminates metastability risk via controlled setup/hold timing and provides glitch-free state capture at up to 10 MHz.

Use Scenario: Generating precise, repeatable stimulus patterns in automated test fixtures for digital IC validation.

IC Role / Device Role / Timing Role: Clock-divided counter stage or pattern sequencer element driving test vector generators.

Use Value: 4 ns propagation delay ensures sub-10 ns timing resolution in pattern generation, critical for high-speed interface testing.

Legacy System Repair

Education & Prototyping

Use Scenario: Replacing obsolete SN74S74N in field-deployed avionics maintenance trainers requiring long-term component availability.

IC Role / Device Role / Timing Role: Drop-in functional replacement preserving original timing behavior and signal integrity.

Use Value: SOIC packaging enables rework onto through-hole boards using adapter sockets or hand-soldered SOIC-to-DIP carriers.

Use Scenario: Teaching sequential logic fundamentals in university labs using breadboard-based digital design experiments.

IC Role / Device Role / Timing Role: Core building block for constructing counters, shift registers, and finite-state machines.

Use Value: Clear pinout labeling, robust noise margins, and predictable edge-triggered behavior simplify student debugging and verification.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74LS74ADR	Slower propagation (15 ns typ), lower drive (8 mA sink), LS-TTL family - consumes less power but limits max clock frequency.	Suitable for low-speed, low-power applications where timing margin is ample; not recommended for >20 MHz designs.	Select SN74LS74ADR only when power budget is constrained and speed requirements are ≤5 MHz.
SN74HC74DR	CMOS technology, 2 V–6 V supply, 18 ns propagation (at 4.5 V), rail-to-rail outputs - incompatible voltage thresholds with TTL.	Requires level-shifting for interfacing with legacy 5 V TTL systems; superior noise immunity and static power efficiency.	Choose SN74HC74DR for new designs targeting mixed-voltage systems or battery-powered operation, not for direct TTL replacement.

Compared with SN74LS74ADR and SN74HC74DR, the SN74S74DR uniquely balances TTL compatibility, 100 MHz-capable timing headroom, and proven reliability in deployed industrial hardware - making it the optimal choice for maintaining legacy performance while ensuring long-term supply stability.

Availability

SN74S74DR is available at Aetrix Electronics and suitable for industrial control logic, digital test equipment, and legacy system repair requiring stable component supply across multi-year production cycles.

Supply support for SN74S74DR 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 deep heritage in TTL and advanced logic families.

The SN74S74DR belongs to TI's legacy 74S logic product line, engineered specifically for high-speed digital systems demanding reliable edge-triggered storage with full TTL interoperability and robust noise margins.

FAQ

What is the maximum clock frequency supported by the SN74S74DR?

The SN74S74DR has a typical propagation delay of 4 ns and a minimum pulse width requirement of 4 ns for both clock high and low periods. This supports reliable operation up to approximately 100 MHz in well-designed PCB layouts with controlled impedance and proper decoupling. Actual maximum frequency depends on setup/hold timing margins and signal integrity in the target system.

Can SN74S74DR replace SN74S74N on a through-hole PCB?

Yes, SN74S74DR can replace SN74S74N functionally and electrically, but not mechanically - SN74S74N uses a 14-pin PDIP package while SN74S74DR uses SOIC-14. A SOIC-to-DIP adapter or rework with a surface-mount carrier is required for direct board-level substitution without redesign.

Does SN74S74DR support asynchronous operation?

Yes, SN74S74DR supports fully asynchronous preset (PR̅) and clear (CLR̅) inputs on each flip-flop section. These active-low controls override clock and data inputs, forcing Q = 1 or Q = 0 immediately - essential for power-on initialization and fault-safe reset sequences in the SN74S74DR.

What are the recommended bypassing practices for SN74S74DR?

A 0.1 µF ceramic capacitor must be placed between V_CC (pin 14) and GND (pin 7) as close as possible to the SN74S74DR package. For systems with multiple SN74S74DR devices, add a bulk 4.7 µF–10 µF tantalum or aluminum electrolytic capacitor per power rail segment to suppress low-frequency ripple and transient droop.

Is SN74S74DR RoHS compliant?

Yes, SN74S74DR is RoHS compliant with NiPdAu lead finish and conforms to JEDEC Level-1 moisture sensitivity. It meets EU Directive 2011/65/EU and is suitable for environmentally regulated commercial and industrial applications without exemption requirements.

SN74S74DR Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74S

Package/Case:: 14-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Function:: Set(Preset) and Reset

Type:: D-Type

Output Type:: Complementary

Number of Elements:: 2

Number of Bits per Element:: 1

Clock Frequency:: 110 MHz

Max Propagation Delay @ V, Max CL:: 9ns @ 5V, 15pF

Trigger Type:: Positive Edge

Current - Output High, Low:: 1mA, 20mA

Voltage - Supply:: 4.75V ~ 5.25V

Current - Quiescent (Iq):: 25 mA

Input Capacitance:: -

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-SOIC

SN74S74DR FAQ

1.How can I place an order for SN74S74DR through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74S74DR 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 SN74S74DR reliable?

The price and inventory of SN74S74DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74S74DR is usually 5 days.

3.What payment methods are accepted for SN74S74DR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74S74DR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74S74DR?

SN74S74DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74S74DR 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 SN74S74DR?

For technical support, including SN74S74DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74S74DR requirements.

6.How does Aetrix verify that SN74S74DR is sourced from the original manufacturer or authorized distributors?

All SN74S74DR 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 SN74S74DR meets industry standards.

7.What is the process for return or replacement of SN74S74DR?

All SN74S74DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74S74DR, 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 SN74S74DR part is unused and in its original packaging.

Return procedure for SN74S74DR:

1.Submit a request within 90 days.

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

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