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Texas Instruments SN74LS74ADBR
- Part No.:
- SN74LS74ADBR
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 14-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74LS74ADBR.pdf
- Description:
- IC FF D-TYPE DUAL 1BIT 14SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:507
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Product details
Overview
SN74LS74ADBR from Texas Instruments is a dual D-type positive-edge-triggered flip-flop IC in SSOP-14 package, operating from 4.75 V to 5.25 V supply, with typical propagation delay of 15 ns and maximum clock frequency of 30 MHz. It serves as a synchronous storage element in digital logic circuits for data latching and state retention in control units and counters.
For engineers reviewing the SN74LS74ADBR datasheet, SN74LS74ADBR pinout, SN74LS74ADBR application, or SN74LS74ADBR equivalent, this page delivers verified functional specifications, validated pin assignments, confirmed industrial temperature range (0°C to 70°C), RoHS-compliant packaging (SSOP-DB), and direct alternative part comparisons for legacy TTL system upgrades and board-level replacements.
Technical Context
The SN74LS74ADBR implements two independent D-type flip-flops, each with separate data (D), clock (CLK), preset (PR), clear (CLR), and complementary outputs (Q, Q̅). Its positive-edge-triggered operation ensures state updates only on rising transitions of CLK, supporting synchronous design methodologies in sequential logic systems.
Designed for LS-TTL compatibility, it features standard 74LS input thresholds (VIH = 2.0 V min, VIL = 0.8 V max), output drive capability of –0.4 mA (high) and 8 mA (low), and operates within the commercial temperature range without derating - making it suitable for stable embedded control and instrumentation interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS (Low-power Schottky TTL) - ensures interoperability with legacy TTL logic families and predictable noise margins. |
| Supply Voltage | 4.75 V to 5.25 V - requires tightly regulated +5 V rail; not tolerant of undervoltage or overvoltage conditions. |
| Max Clock Frequency | 30 MHz - supports medium-speed digital control loops and counter applications up to 30 million state transitions per second. |
| Propagation Delay | 15 ns (typical, CL = 15 pF) - determines minimum clock period and timing margin in synchronous state machines. |
| Output Drive | –0.4 mA (VOH), 8 mA (VOL) - drives up to 20 LS-TTL inputs or one standard TTL input without buffering. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade environments including office equipment, test instruments, and industrial controllers. |
| Package | SSOP-14 (DB) - surface-mount, 2000-unit tape-and-reel format with 0.65 mm lead pitch; requires fine-pitch PCB layout and reflow profile compliance. |
Pinout & Package
SN74LS74ADBR uses a 14-pin Shrink Small Outline Package (SSOP-DB), 5.9 mm × 4.4 mm body size, 2.0 mm max height, with gull-wing leads spaced at 0.65 mm pitch. Pin 1 is located at the top-left corner with index marking in the upper-left quadrant of the tape reel.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1CLR | Asynchronous active-low clear for first flip-flop - forces Q1 = 0 regardless of clock or data state. |
| 2 | 1D | Data input for first flip-flop - sampled on rising edge of CLK1 and transferred to Q1. |
| 3 | 1CLK | Positive-edge-triggered clock for first flip-flop - controls timing of data capture into Q1/Q1̅. |
| 4 | 1PR | Asynchronous active-low preset for first flip-flop - forces Q1 = 1 independently of clock or data. |
| 5 | 1Q | True output of first flip-flop - reflects stored D value after clock edge, unless overridden by PR/CLR. |
| 6 | 1Q̅ | Inverted output of first flip-flop - always complementary to 1Q when flip-flop is enabled and stable. |
| 7 | GND | Ground reference for all internal circuitry - must be low-impedance connection to minimize noise coupling. |
| 8 | 2Q̅ | Inverted output of second flip-flop - complements 2Q; used for feedback or differential signaling paths. |
| 9 | 2Q | True output of second flip-flop - provides synchronized storage for independent data path or dual-phase timing. |
| 10 | 2PR | Asynchronous active-low preset for second flip-flop - sets Q2 = 1 unconditionally. |
| 11 | 2CLK | Positive-edge-triggered clock for second flip-flop - enables independent timing control from 1CLK. |
| 12 | 2D | Data input for second flip-flop - isolated from first section; supports dual-channel register functionality. |
| 13 | 2CLR | Asynchronous active-low clear for second flip-flop - resets Q2 = 0 regardless of clock or data. |
| 14 | VCC | +5 V power supply - must be decoupled locally with 0.1 µF ceramic capacitor near pin 14. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent D flip-flops | Enables compact implementation of two-bit registers, shift registers, or toggle configurations without external gating. |
| Asynchronous preset and clear | Allows immediate initialization or reset of each flip-flop without waiting for clock edge - critical for power-up sequencing and fault recovery. |
| Positive-edge clock triggering | Supports clean synchronization in systems where clock rise time is well-controlled and jitter is bounded. |
| LS-TTL compatible I/O levels | Guarantees interoperability with 74LS, 74S, and 74F families without level-shifting components. |
| RoHS-compliant NIPDAU finish | Meets environmental compliance requirements for commercial electronics manufacturing and end-of-life disposal. |
Applications
| Counter Design | State Machine Control |
|---|---|
Use Scenario: Building a 4-bit binary counter using cascaded SN74LS74ADBR devices with feedback logic. IC Role / Device Role / Timing Role: Each SN74LS74ADBR provides two synchronized bits; clock edges propagate through stages to increment count. Use Value: Enables deterministic, glitch-free counting up to 30 MHz with minimal external logic due to built-in edge-triggered behavior. | Use Scenario: Implementing a 3-state traffic light controller with defined transition logic and reset-on-fault capability. IC Role / Device Role / Timing Role: SN74LS74ADBR stores current state (e.g., Red/Yellow/Green) and advances on system clock edge. Use Value: Asynchronous PR/CLR pins allow immediate return to safe state (e.g., all-red) during error detection without clock dependency. |
| Data Synchronization | Glitch-Free Latching |
Use Scenario: Capturing asynchronous sensor data (e.g., encoder pulses) into a synchronous microcontroller bus. IC Role / Device Role / Timing Role: SN74LS74ADBR acts as a synchronizer stage between asynchronous domain and system clock domain. Use Value: Dual flip-flop structure allows metastability mitigation via cascaded sampling, reducing failure probability in real-time systems. | Use Scenario: Holding display segment data in a multiplexed LED driver where output must remain stable during scan cycles. IC Role / Device Role / Timing Role: SN74LS74ADBR latches parallel data on rising clock edge and holds until next update. Use Value: Eliminates visual flicker by ensuring outputs change only at precise clock instants - no race conditions or partial updates. |
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 | SOIC-14 package (wider 1.27 mm pitch), same electrical specs and timing. | Preferred for through-hole prototyping or legacy PCBs with SOIC footprints; less dense than SSOP. | Select SN74LS74ADR when board space permits larger footprint or reworkability is prioritized over miniaturization. |
| SN74LS74ANSR | SOP-14 (NS) package with 1.27 mm pitch and 10.4 mm body width; identical logic function and DC specs. | Used in cost-sensitive consumer electronics where SOP handling and assembly infrastructure already exist. | Choose SN74LS74ANSR for high-volume production where SOP tooling and supply chain maturity reduce total cost of ownership. |
Compared with SN74LS74ADR and SN74LS74ANSR, the SN74LS74ADBR offers the smallest PCB footprint (SSOP-DB) and highest density mounting, while maintaining full functional equivalence and identical timing behavior - making it optimal for space-constrained industrial control modules and portable instrumentation.
Availability
SN74LS74ADBR is available at Aetrix Electronics and suitable for industrial control panels, test instrumentation, and legacy TTL-based communication interfaces requiring stable component supply across long product lifecycles.
Supply support for SN74LS74ADBR 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 specializing in analog, embedded processing, and logic solutions with over 90 years of innovation in reliable, high-volume component design.
The SN74LS74ADBR belongs to TI's legacy 74LS logic family, engineered for robust performance in commercial-grade digital systems where compatibility, predictability, and long-term availability are essential.
FAQ
What is the maximum operating frequency of the SN74LS74ADBR?
The SN74LS74ADBR supports a maximum clock frequency of 30 MHz under standard load conditions (CL = 15 pF). This limit arises from its 15 ns typical propagation delay and internal gate delays inherent to LS-TTL technology. Operation above 30 MHz risks setup/hold violations and metastability, especially with marginal signal integrity or elevated temperature.
Does the SN74LS74ADBR support asynchronous reset and preset functions?
Yes, the SN74LS74ADBR provides dedicated active-low asynchronous inputs: 1CLR and 1PR for the first flip-flop, and 2CLR and 2PR for the second. These override clock and data signals to force Q = 0 or Q = 1 immediately, enabling reliable power-on initialization and fault-safe state recovery without waiting for a clock edge.
Can the SN74LS74ADBR be used with modern 3.3 V logic systems?
No, the SN74LS74ADBR is strictly a 5 V device with 4.75 V to 5.25 V supply requirement and LS-TTL input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V). Direct interface with 3.3 V logic risks insufficient high-level input voltage and potential damage from output voltage overshoot; level-shifting circuitry is required for interoperability.
What is the recommended PCB layout practice for the SN74LS74ADBR?
Place a 0.1 µF ceramic decoupling capacitor between VCC (pin 14) and GND (pin 7) as close as possible to the device. Maintain short, direct traces for clock and control lines; avoid routing sensitive signals adjacent to noisy power or switching nodes. Use the TI-recommended SSOP land pattern (DB0014A) with 0.45 mm pad width and 1.85 mm length to ensure reliable solder joint formation.
Is the SN74LS74ADBR pin-compatible with other 74LS74 variants?
Yes, the SN74LS74ADBR shares identical pinout and logic function with all 74LS74 family members including SN74LS74ADR (SOIC), SN74LS74ANSR (SOP), and SN74LS74AN (PDIP). All variants use the same 14-pin assignment for dual D flip-flop I/O, allowing direct substitution when package constraints permit.
SN74LS74ADBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 14-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Set(Preset) and Reset
- Type:
- D-Type
- Output Type:
- Complementary
- Number of Elements:
- 2
- Number of Bits per Element:
- 1
- Clock Frequency:
- 33 MHz
- Max Propagation Delay @ V, Max CL:
- 40ns @ 5V, 15pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 400µA, 8mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Iq):
- 8 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SSOP
SN74LS74ADBR FAQ
1.How can I place an order for SN74LS74ADBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS74ADBR 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 SN74LS74ADBR reliable?
The price and inventory of SN74LS74ADBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS74ADBR is usually 5 days.
3.What payment methods are accepted for SN74LS74ADBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS74ADBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS74ADBR?
SN74LS74ADBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS74ADBR 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 SN74LS74ADBR?
For technical support, including SN74LS74ADBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS74ADBR requirements.
6.How does Aetrix verify that SN74LS74ADBR is sourced from the original manufacturer or authorized distributors?
All SN74LS74ADBR 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 SN74LS74ADBR meets industry standards.
7.What is the process for return or replacement of SN74LS74ADBR?
All SN74LS74ADBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS74ADBR, 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 SN74LS74ADBR part is unused and in its original packaging.
Return procedure for SN74LS74ADBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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