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Texas Instruments SNJ54LS109AJ
- Part No.:
- SNJ54LS109AJ
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- -
- Datasheet:
-
SNJ54LS109AJ.pdf
- Description:
- 54LS109A DUAL J-K POSITIVE-EDGE-
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Product details
Overview
SNJ54LS109AJ from Texas Instruments is a dual J-K positive-edge-triggered flip-flop with individual set and reset inputs, designed for synchronous logic control in military-grade systems. It operates across -55°C to +125°C, features 16-pin CDIP (J) packaging, supports TTL-compatible input thresholds, and delivers typical propagation delay of 15 ns at VCC = 5 V.
For engineers reviewing the SNJ54LS109AJ datasheet, SNJ54LS109AJ pinout, SNJ54LS109AJ application, or SNJ54LS109AJ equivalent, this device is selected for high-reliability timing, state sequencing, and clock-synchronized data latching in aerospace avionics, defense electronics, and ruggedized industrial controllers where extended temperature operation and leaded hermetic packaging are required.
Technical Context
The SNJ54LS109AJ implements two independent edge-triggered J-K flip-flops, each with asynchronous active-low Set (SD̅) and Reset (RD̅) inputs, and synchronous J, K, and clock (CP) terminals. Its logic conforms to standard TTL voltage levels and fan-out capability of 10 LS-TTL loads.
It uses bipolar transistor–transistor logic (TTL) architecture with Schottky-clamped outputs, enabling fast switching while suppressing saturation delay. The device requires a single +5 V supply and draws typical quiescent current of 24 mA at 25°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | LS-TTL - ensures compatibility with legacy 74LS-series systems and predictable noise margins. |
| Operating Temperature | -55°C to +125°C - qualified for extended-range military applications per MIL-PRF-38535. |
| Propagation Delay (tPLH/tPHL) | 15 ns max (at VCC = 5 V, TA = 25°C) - defines maximum clock-to-output timing for synchronous state updates. |
| Supply Voltage | 4.5 V to 5.5 V - supports stable operation under regulated or filtered 5 V rails in harsh environments. |
| Output Drive | IOL = 8 mA / IOH = -0.4 mA - sufficient to directly drive multiple LS-TTL inputs without buffering. |
| Package Type | CDIP (J), 16-pin - hermetically sealed ceramic dual in-line package for moisture resistance and thermal stability. |
Pinout & Package
SNJ54LS109AJ is housed in a 16-pin Ceramic Dual In-line Package (CDIP, suffix J), with 0.3-inch body width and through-hole mounting. Pin 1 is located at the left end of the top row, identified by a notch or dot marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (1SD̅) | Asynchronous Set (Channel 1) | Active-low direct set - forces Q1 high regardless of clock or J/K state. |
| 2 (1Q) | True Output (Channel 1) | Complements 1Q̅; provides primary registered output signal. |
| 3 (1Q̅) | Inverted Output (Channel 1) | Complements 1Q; enables differential signaling or feedback without external inversion. |
| 4 (1J) | Data Input J (Channel 1) | Controls set behavior on next positive clock edge when K = 0. |
| 5 (1CP) | Clock Input (Channel 1) | Positive-edge-triggered - samples J/K inputs only at rising transition. |
| 6 (1K) | Data Input K (Channel 1) | Controls reset behavior on next positive clock edge when J = 0. |
| 7 (1RD̅) | Asynchronous Reset (Channel 1) | Active-low direct reset - forces Q1 low independently of clock. |
| 8 (GND) | Ground Reference | Power return path for all internal circuitry and output drivers. |
| 9 (2RD̅) | Asynchronous Reset (Channel 2) | Independent active-low reset for second flip-flop section. |
| 10 (2K) | Data Input K (Channel 2) | Functional mirror of Pin 6 for second channel. |
| 11 (2CP) | Clock Input (Channel 2) | Independent positive-edge clock for second flip-flop. |
| 12 (2J) | Data Input J (Channel 2) | Functional mirror of Pin 4 for second channel. |
| 13 (2Q̅) | Inverted Output (Channel 2) | Functional mirror of Pin 3 for second channel. |
| 14 (2Q) | True Output (Channel 2) | Functional mirror of Pin 2 for second channel. |
| 15 (2SD̅) | Asynchronous Set (Channel 2) | Functional mirror of Pin 1 for second channel. |
| 16 (VCC) | Positive Supply | +5 V DC power input - must be decoupled locally with 0.1 µF ceramic capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent J-K flip-flops | Enables compact implementation of two-bit synchronous counters or shift register stages without inter-chip routing. |
| Asynchronous set/reset per channel | Allows immediate state initialization or fault recovery without waiting for clock edges - critical for safety-critical sequencers. |
| Positive-edge clock triggering | Eliminates metastability risk from level-sensitive sampling and synchronizes state changes precisely to system clock edges. |
| Hermetic CDIP packaging | Provides long-term reliability in high-humidity, high-vibration, or radiation-prone environments where plastic packages degrade. |
| MIL-PRF-38535 Class B qualification | Confirms compliance with military screening including burn-in, temperature cycling, and lot acceptance testing for mission-critical use. |
Applications
| Avionics Flight Control Sequencing | Tactical Radio Channel State Management |
|---|---|
|
Use Scenario: Latching command execution states during autopilot mode transitions under vibration and wide-temperature operation. IC Role / Device Role / Timing Role: Dual J-K flip-flop providing synchronized, glitch-free state storage for flight control finite-state machine registers. Use Value: Asynchronous reset ensures deterministic recovery from transient faults; CDIP package maintains integrity across -55°C to +125°C operational envelope. |
Use Scenario: Managing transmit/receive channel enable states in software-defined radios deployed in mobile military platforms. IC Role / Device Role / Timing Role: Edge-triggered storage element capturing digital control bits from FPGA-based baseband processors. Use Value: 15 ns propagation delay supports tight timing budgets in multi-channel RF resource allocation logic. |
| Secure Data Encryption Key Register | Ruggedized Industrial PLC I/O Latching |
|
Use Scenario: Holding cryptographic key bits during secure boot sequences where tamper-resistant state retention is mandatory. IC Role / Device Role / Timing Role: Non-volatile-capable latch (with external hold circuitry) preserving sensitive configuration bits between power cycles. Use Value: TTL-compatible inputs interface directly with anti-tamper monitoring circuits; SNPB finish avoids lead-free reflow compatibility issues in legacy assemblies. |
Use Scenario: Capturing sensor input states in programmable logic controllers operating in factory environments with EMI and thermal stress. IC Role / Device Role / Timing Role: Synchronous input register isolating field-side signals from CPU clock domain. Use Value: Dual-channel integration reduces board space vs. discrete latches; MIL-spec temperature range eliminates derating concerns in uncooled enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual J-K flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN54LS109AJ | Identical electrical specs and CDIP (J) package; differs only in part marking and internal lot traceability per MIL-STD-883. | No functional difference - used interchangeably in new designs requiring full QML-38535 Class B certification. | Select SN54LS109AJ when full QML documentation and traceability to MIL-PRF-38535 Rev G are contractually mandated. |
| SNJ54LS109AW | Same logic function and temperature range, but in 16-pin CFP (W) metal-can package with different pin 1 orientation and thermal profile. | Preferred for conduction-cooled modules or where lower thermal resistance (<120°C/W junction-to-case) is required over CDIP. | Choose SNJ54LS109AW when board-level thermal management relies on case conduction rather than ambient convection. |
Compared with SN54LS109AJ and SNJ54LS109AW, the SNJ54LS109AJ offers identical logic behavior and military temperature rating but is optimized for standard through-hole assembly with notch-aligned pin 1 orientation and proven long-term hermeticity in CDIP form - making it the default choice for legacy avionics upgrades and new designs prioritizing manufacturability and field reliability over thermal conduction.
Availability
SNJ54LS109AJ is available at Aetrix Electronics and suitable for aerospace avionics, defense communications, and ruggedized industrial control systems requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for SNJ54LS109AJ 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 founded in 1930, specializing in analog, embedded processing, and high-reliability logic solutions for industrial, automotive, and defense markets.
The SNJ54LS109AJ belongs to TI's military-grade 54LS logic family, engineered for deterministic timing, radiation-tolerant operation, and long-term reliability in mission-critical systems where failure is not an option.
FAQ
What is the maximum clock frequency supported by SNJ54LS109AJ?
The SNJ54LS109AJ does not specify a maximum clock frequency in its datasheet; instead, it guarantees a maximum propagation delay of 15 ns (tPLH/tPHL) and setup/hold times of 20 ns and 5 ns respectively. Designers derive usable clock rates from these timing parameters - typically up to 25 MHz in well-decoupled, low-skew layouts. The SNJ54LS109AJ remains functional beyond this range but requires careful PCB-level timing analysis to ensure reliable edge capture.
Is SNJ54LS109AJ RoHS compliant?
No, SNJ54LS109AJ is not RoHS compliant. It uses SnPb (tin-lead) lead finish per MIL-PRF-38535 requirements and is marked "No" in TI's official packaging documentation. This makes it suitable for legacy military and aerospace systems requiring leaded solder compatibility and exempt from EU RoHS Directive restrictions under Annex III exemptions for high-reliability applications.
Can SNJ54LS109AJ be used as a drop-in replacement for SN74LS109AN?
No, SNJ54LS109AJ is not a drop-in replacement for SN74LS109AN. While both implement identical J-K flip-flop logic, they differ in temperature range (-55°C to +125°C vs. 0°C to +70°C), package type (CDIP vs. PDIP), lead finish (SnPb vs. NiPdAu), and qualification level (MIL-PRF-38535 Class B vs. commercial). Board layout, thermal design, and system-level qualification must be revalidated when substituting SNJ54LS109AJ into a design originally using SN74LS109AN.
What is the purpose of the separate SD̅ and RD̅ pins on SNJ54LS109AJ?
The SNJ54LS109AJ provides dedicated active-low Set (SD̅) and Reset (RD̅) inputs for each flip-flop channel to enable immediate, clock-independent state control. These asynchronous inputs allow hard-wired initialization, emergency shutdown, or fault recovery without waiting for the next clock edge - a requirement in safety-critical systems like flight control computers where deterministic reset timing is non-negotiable. The SNJ54LS109AJ asserts Q = 1 on SD̅ low and Q = 0 on RD̅ low, regardless of J, K, or CP state.
Does SNJ54LS109AJ require external pull-up resistors on its inputs?
No, SNJ54LS109AJ does not require external pull-up resistors on its J, K, CP, SD̅, or RD̅ inputs. Its TTL-compatible inputs have built-in multi-emitter transistor structures that source current internally, allowing direct connection to TTL or CMOS outputs. However, floating inputs must be avoided - unused J/K inputs should be tied to VCC or GND, and unused SD̅/RD̅ inputs should be held high (via VCC) to prevent unintended set/reset activation. This behavior is inherent to the SNJ54LS109AJ's bipolar TTL input stage design.
SNJ54LS109AJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- -
- Type:
- -
- Output Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Clock Frequency:
- -
- Max Propagation Delay @ V, Max CL:
- -
- Trigger Type:
- -
- Current - Output High, Low:
- -
- Voltage - Supply:
- -
- Current - Quiescent (Iq):
- -
- Input Capacitance:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SNJ54LS109AJ FAQ
1.How can I place an order for SNJ54LS109AJ through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54LS109AJ 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 SNJ54LS109AJ reliable?
The price and inventory of SNJ54LS109AJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54LS109AJ is usually 5 days.
3.What payment methods are accepted for SNJ54LS109AJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54LS109AJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SNJ54LS109AJ?
SNJ54LS109AJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54LS109AJ 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 SNJ54LS109AJ?
For technical support, including SNJ54LS109AJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54LS109AJ requirements.
6.How does Aetrix verify that SNJ54LS109AJ is sourced from the original manufacturer or authorized distributors?
All SNJ54LS109AJ 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 SNJ54LS109AJ meets industry standards.
7.What is the process for return or replacement of SNJ54LS109AJ?
All SNJ54LS109AJ units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54LS109AJ, 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 SNJ54LS109AJ part is unused and in its original packaging.
Return procedure for SNJ54LS109AJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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