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HomeProductsIntegrated Circuits (ICs)Logic - Flip FlopsSN74ALS109AD
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SN74ALS109AD - Texas Instruments

Manufacturer Part Number
SN74ALS109AD
Manufacturer
Texas Instruments
Allelco Part Number
32D-SN74ALS109AD
Warranty
1 Year Allelco Warranty - Find out more
Stock Status:
40,690 pcs available, New & Original
Parts Description
IC FF JK TYPE DUAL 1BIT 16SOIC
Package
16-SOIC
Data sheet
SN74ALS109AD.pdf

HTML Datasheet

SN54/74(ALS,AS)109A.pdf
RoHs Status
ROHS3 Compliant
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In stock: 40690

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Specifications

SN74ALS109AD Tech Specifications
Texas Instruments - SN74ALS109AD technical specifications, attributes, parameters and parts with similar specifications to Texas Instruments - SN74ALS109AD

Product Attribute Attribute Value
Manufacturer Texas Instruments
Voltage - Supply 4.5V ~ 5.5V
Type JK Type
Trigger Type Positive Edge
Supplier Device Package 16-SOIC
Series 74ALS
Package / Case 16-SOIC (0.154", 3.90mm Width)
Package Tube
Output Type Complementary
Operating Temperature 0°C ~ 70°C (TA)
Product Attribute Attribute Value
Number of Elements 2
Number of Bits per Element 1
Mounting Type Surface Mount
Max Propagation Delay @ V, Max CL 18ns @ 5V, 50pF
Function Set(Preset) and Reset
Current - Quiescent (Iq) 4 mA
Current - Output High, Low 400µA, 8mA
Clock Frequency 34 MHz
Base Product Number 74ALS109

Environmental & Export Classifications

ATTRIBUTE DESCRIPTION
RoHs Status ROHS3 Compliant
Moisture Sensitivity Level (MSL) 1 (Unlimited)
REACH Status REACH Unaffected
ECCN EAR99
HTSUS 8542.39.0001

Parts Introduction

SN74ALS109AD Image
SN74ALS109AD (1)

Manufacturer Part Number

SN74ALS109AD

Manufacturer

Texas Instruments

Introduction

The SN74ALS109AD is a dual JK-type flip-flop with independent set (preset) and reset functions. It features high-speed operation and complementary outputs, making it suitable for a wide range of digital logic applications.

Product Features and Performance

Dual JK-type flip-flop with independent set (preset) and reset functions

High-speed operation with a clock frequency of up to 34 MHz

Complementary outputs

Low propagation delay of 18 ns at 5 V and 50 pF load

Positive edge-triggered

Product Advantages

Versatile and flexible digital logic functionality

High-speed operation for efficient and fast data processing

Complementary outputs for easy integration into various circuit designs

Low power consumption and wide voltage supply range

Key Reasons to Choose This Product

Reliable and high-performance digital logic solution

Suitable for a wide range of applications, from digital circuits to industrial controls

Cost-effective and readily available from a trusted manufacturer

Backed by Texas Instruments' reputation for quality and innovation

Quality and Safety Features

Manufactured using advanced semiconductor technology for reliable performance

Complies with industry standards and safety regulations

Robust design and packaging for durability and long-term use

Compatibility

Compatible with a variety of digital logic families, including 74ALS and TTL

Can be used in a wide range of electronic systems and applications

Application Areas

Digital logic circuits

Industrial automation and control systems

Computer and peripheral devices

Telecommunications equipment

Consumer electronics

Product Lifecycle

The SN74ALS109AD is an active and widely available product from our website's sales team. There are equivalent or alternative models available, such as the SN74ALS109A and SN74ALS109. Customers are advised to contact our website's sales team for the latest product information and availability.

Frequently Asked Questions(FAQ)

How does the propagation delay of the SN74ALS109AD compare between typical and maximum supply voltage conditions when driving a 50pF load?
The SN74ALS109AD exhibits a propagation delay of 18ns at maximum supply voltage (5.5V) and load capacitance (50pF), but this improves to approximately 12–14ns under typical 5V operation with similar loading. This variation reflects the nonlinear relationship between supply voltage and internal transistor switching thresholds in advanced logic families like ALS. Designers targeting high-speed synchronous systems must account for worst-case timing margins, particularly when cascading multiple flip-flops or interfacing with other logic families that may have different delay characteristics.
What is the impact of temperature on the clock frequency performance of the SN74ALS109AD across its industrial operating range?
While the SN74ALS109AD specifies a maximum clock frequency of 34 MHz at room temperature (25°C), this rating assumes optimal laboratory conditions including stable power and minimal capacitive loading. Over the full commercial temperature range (0°C to 70°C), derating due to increased leakage currents and slower carrier mobility in bipolar transistors typically reduces usable bandwidth by 10–15%. In practice, most applications should design for no more than 30–32 MHz to ensure reliable edge-triggered operation under thermal stress.
Can the SN74ALS109AD be safely used in a dual-clock asynchronous counter configuration without additional synchronization circuitry?
Although the SN74ALS109AD contains two independent JK flip-flops capable of forming a decade counter when connected as a divide-by-two cascade, using them in an asynchronous mode across separate clock domains introduces metastability risks. Without explicit synchronizer chains—typically two D-type flip-flops clocked from the secondary domain—the probability of incorrect state capture rises significantly during clock domain crossings. For robust designs, either use synchronous counters or implement proper CDC mitigation techniques.
How much current can each output of the SN74ALS109AD source or sink before experiencing significant signal degradation or reliability concerns?
Each output stage of the SN74ALS109AD is rated for 400µA sourcing and 8mA sinking capability. However, these are absolute limits based on junction temperature and packaging constraints. Sustained operation near 8mA may cause localized heating within the SOIC package, especially in compact layouts with poor thermal dissipation. Most digital designs limit outputs to ≤1mA per pin to preserve timing margins and reduce electromagnetic interference; only bus drivers or LED indicators justify higher current draws, often requiring external buffering.
What are the key differences between using the preset (PRE) and clear (CLR) inputs versus direct set/reset functionality in the SN74ALS109AD for control logic applications?
The SN74ALS109AD provides asynchronous active-low preset and clear inputs that override the JK logic immediately upon assertion, regardless of the clock edge. Unlike synchronous set/reset methods, these allow instant state changes useful for initialization or emergency shutdowns. However, simultaneous assertion of PRE and CLR creates an indeterminate state unless prevented by firmware or hardware debouncing. Designers must ensure mutual exclusion in safety-critical systems or add glitch filters to prevent race conditions during power-up sequences.
Is it feasible to parallel multiple SN74ALS109AD devices to increase fan-out or drive capacity in high-speed data paths?
While electrically possible, paralleling SN74ALS109AD outputs to increase drive strength introduces skew and mismatch issues that degrade signal integrity at frequencies above 10 MHz. The complementary output structure means one device will dominate unless perfectly matched in propagation delay and threshold voltages. Instead, consider using dedicated buffer ICs like the SN74LVC244A or adding series resistors with external emitter followers. Parallel use is acceptable only for low-frequency control signals where timing alignment is less critical.
How does the quiescent current of the SN74ALS109AD affect battery-powered system longevity compared to newer low-power alternatives?
At 4 mA quiescent current per package under nominal 5V operation, the SN74ALS109AD consumes roughly 20 mW continuously—a significant drain in energy-constrained environments. A modern CMOS equivalent such as the 74LVC109 might draw <1 µA, improving battery life by over three orders of magnitude. When designing portable instruments or IoT nodes, replacing ALS-series components with LVC or AHC families yields substantial power savings, though at the cost of reduced noise immunity and slightly higher propagation delay.
What precautions should be taken when routing the SN74ALS109AD in mixed-signal PCB layouts to minimize crosstalk and ground bounce?
The SN74ALS109AD’s relatively fast rise/fall times (~2–3 ns) generate high-frequency harmonics that couple into adjacent traces via capacitive and inductive coupling. To mitigate this, maintain at least 3× trace width spacing from sensitive analog lines, avoid running digital nets perpendicularly over return planes, and use solid ground pours beneath the component. Additionally, place bypass capacitors (0.1 µF ceramic) as close as possible to VCC and GND pins to suppress supply rail oscillations caused by switching currents in the dual-element architecture.

Parts with Similar Specifications

The three parts on the right have similar specifications to Texas Instruments SN74ALS109AD

Product Attribute SN74ALS109ADR SN74ALS109ADG4 SN74ALS109ANSR SN74ALS109ANS
Part Number SN74ALS109ADR SN74ALS109ADG4 SN74ALS109ANSR SN74ALS109ANS
Manufacturer Texas Instruments Texas Instruments Texas Instruments Texas Instruments
Package / Case - 196-LFBGA 16-DIP (0.300', 7.62mm) 64-VFQFN Exposed Pad
Trigger Type - - - -
Current - Output High, Low - - - -
Mounting Type - Surface Mount Through Hole Surface Mount
Max Propagation Delay @ V, Max CL - - - -
Type - - - -
Package - Tape & Reel (TR) Tube Tape & Reel (TR)
Number of Bits per Element - - - -
Base Product Number - DAC34H84 MAX500 ADS62P42
Current - Quiescent (Iq) - - - -
Output Type - Current - Unbuffered Voltage - Buffered -
Operating Temperature - -40°C ~ 85°C 0°C ~ 70°C -40°C ~ 85°C
Series - - - -
Function - - - -
Clock Frequency - - - -
Number of Elements - - - -
Voltage - Supply - - - -
Supplier Device Package - 196-NFBGA (12x12) 16-PDIP 64-VQFN (9x9)

SN74ALS109AD Datasheet PDF

Download SN74ALS109AD pdf datasheets and Texas Instruments documentation for SN74ALS109AD - Texas Instruments.

HTML Datasheet
SN54/74(ALS,AS)109A.pdf

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Customer Reviews

Evaluation: 10 Articles

  • Nath***rooks
    Jun 11, 2026

    Installed this power component in a converter board. Output remained stable under different load conditions and thermal performance was better than expected.

  • Dani***alkerTech
    Jun 1, 2026

    Product works, but setup took more effort than expected. Once configured the MCU ran reliably, although documentation support felt older compared with newer platforms. Fine for maintenance projects.

  • Yuki***aka88
    May 26, 2026

    信号通信プロジェクトでこのRS-485トランシーバーを使用しました。設置は簡単で、長距離ケーブルでも通信は安定していました。消費電力も、以前使用していたものより低くなっています。

  • Stev***aker
    May 20, 2026

    Solid diode for power rectification. Works well in switching circuits.

  • Bran***Lewis
    May 11, 2026

    Compact FPGA with good performance. Suitable for basic signal processing tasks.

  • Oliv***arris
    May 7, 2026

    Reliable I/O expander. Works well in embedded control applications.

  • Jess***Jones
    Apr 17, 2026

    It offers good value for the price, and the specifications match the description. I’ve been using it for two days with no issues, and I’ll definitely buy it again if I need it in the future.

  • Mich***Smith
    Apr 17, 2026

    Shipping was on time, the component pins are neatly aligned, and I tested 10 of them with a multimeter—all readings were within the specified range. Highly recommended.

  • Aman***arris
    Apr 3, 2026

    It was great—the entire process, from placing the order to receiving the package, went very smoothly. The components were consistent, the price was fair, and I had a very pleasant shopping experience.

  • Mike***nch
    Apr 3, 2026

    Better than expected! The resistance and capacitance readings were spot-on, and it passed the test on the first try. The service was reliable, and the packaging was thoughtful—I highly recommend it.

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Delivery Time

In-stock items can be shipped within 24 hours. Some parts will be arranged for delivery within 1-2 days from the date all items arrive at our warehouse. And Allelco ships order once a day at about 17:00, except Sunday. Once the goods are shipped, the estimated delivery time depends on the shipping methods and Delivery destination. The table below shows are the logistic time for some common countries.

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Common Countries Logistic Time Reference
Region Country Logistic Time(Day)
America United States 5
Brazil 7
Europe Germany 5
United Kingdom 4
Italy 5
Oceania Australia 6
New Zealand 5
Asia India 4
Japan 4
Middle East Israel 6
DHL & FedEx Shipment Charges Reference
Shipment charges(KG) Reference DHL(USD$)
0.00kg-1.00kg USD$30.00 - USD$60.00
1.00kg-2.00kg USD$40.00 - USD$80.00
2.00kg-3.00kg USD$50.00 - USD$100.00
Note:
The above table is for reference only. There may have some data bias for the uncontrollable factors.
Contact us if you have any questions.
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Electrostatic Discharge Protection and Handling

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SN74ALS109AD Image

SN74ALS109AD

Texas Instruments
32D-SN74ALS109AD

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