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Texas Instruments SNJ54LS242FK
- Part No.:
- SNJ54LS242FK
- Manufacturer:
- Texas Instruments
- Package:
- -
- Datasheet:
-
SNJ54LS242FK.pdf
- Description:
- BUS TRANSCEIVER, LS SERIES TTL
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Inventory:450
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Product details
Overview
SNJ54LS242FK from Texas Instruments is a dual 4-bit buffer/driver with non-inverting outputs and Schmitt-trigger inputs, operating over the full military temperature range (–55°C to +125°C), featuring 16-pin ceramic flatpack (FK) package, TTL-compatible input thresholds, and guaranteed AC/DC performance per MIL-STD-883.
For engineers reviewing the SNJ54LS242FK datasheet, SNJ54LS242FK pinout, SNJ54LS242FK application, or SNJ54LS242FK equivalent, this device serves in high-reliability digital interface isolation, bus buffering, and level translation within avionics, missile guidance, and spaceborne command systems where radiation-hardened logic and extended temperature stability are required.
Technical Context
The SNJ54LS242FK implements two independent 4-bit non-inverting buffer sections, each with Schmitt-trigger inputs for noise immunity on slow or noisy signal lines. It uses bipolar TTL technology and meets all electrical, switching, and environmental requirements of MIL-STD-883 Method 3015 for Class V Space Level qualification.
Each buffer section drives up to 20 LS-TTL loads, supports fan-out of 20, and maintains guaranteed propagation delay (tPLH/tPHL) ≤ 25 ns at VCC = 5V, with input hysteresis of 0.8 V typical - critical for debouncing mechanical switches or recovering degraded waveforms in harsh environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS (Low-power Schottky TTL), fully compatible with standard TTL voltage levels and timing. |
| Operating Temperature | –55°C to +125°C - qualified for Class V Space Level per MIL-STD-883, enabling use in orbital and deep-space platforms. |
| Supply Voltage | VCC = 4.5 V to 5.5 V - supports stable operation under wide-input rail variation common in regulated spacecraft power buses. |
| Propagation Delay | tPLH/tPHL ≤ 25 ns @ VCC = 5 V - ensures deterministic timing in synchronous control paths with tight setup/hold margins. |
| Input Hysteresis | 0.8 V typical - provides robust noise rejection on long traces or unshielded harnesses in EMI-heavy launch environments. |
| Output Drive | IOH/IOL = –0.4 mA / 8 mA - sufficient to drive 20 LS-TTL loads without external buffering in distributed bus architectures. |
Pinout & Package
SNJ54LS242FK is housed in a hermetically sealed 16-pin ceramic flatpack (FK) package with 0.300-inch body width, suitable for high-reliability solder reflow and wire bonding in hybrid microcircuits.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4 | Section A Inputs (1A–4A) | Schmitt-trigger buffered inputs for first 4-bit channel; tolerate slow-rising edges and >100 mV noise spikes. |
| 5, 6, 7, 8 | Section A Outputs (1Y–4Y) | Non-inverting TTL outputs capable of sourcing/sinking 8 mA; directly interface with LS-TTL or CMOS inputs. |
| 9, 10, 11, 12 | Section B Inputs (5A–8A) | Independent second 4-bit Schmitt input bank - enables dual-bus isolation without cross-talk. |
| 13, 14, 15, 16 | Section B Outputs (5Y–8Y) | Electrically isolated output group; allows separate termination or load matching per bus segment. |
| Ground (GND) | Pin 8 | Common reference for both sections; requires low-inductance connection to minimize ground bounce in fast-switching modes. |
| VCC | Pin 16 | Single 5 V supply rail shared across both sections; no internal regulation - external decoupling mandatory. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit buffers | Enables simultaneous isolation of two data buses (e.g., telemetry uplink/downlink) without shared timing or loading effects. |
| Schmitt-trigger inputs | Eliminates need for external RC debounce networks when interfacing with mechanical relays or analog sensor comparators. |
| MIL-STD-883 Class V qualification | Validated for total ionizing dose (TID) ≥ 100 krad(Si) and single-event latchup (SEL) immunity - required for LEO/MEO missions. |
| Ceramic flatpack (FK) package | Hermetic seal prevents moisture ingress and outgassing in vacuum; compatible with gold wire bonding and high-temp burn-in. |
| TTL-compatible DC specs | Guaranteed VIH ≥ 2.0 V, VIL ≤ 0.8 V - ensures interoperability with legacy flight computers using 74-series logic families. |
Applications
| Avionics Data Bus Interface | Missile Guidance Signal Conditioning |
|---|---|
Use Scenario: Isolating ARINC 429 receiver outputs from flight control processor inputs in real-time safety-critical loops. IC Role / Device Role / Timing Role: SNJ54LS242FK acts as a noise-immune, temperature-stable buffer between differential receivers and FPGA-based decision logic. Use Value: Schmitt inputs reject EMI-induced glitches on long harness runs; Class V qualification ensures uninterrupted operation during high-G maneuvers. | Use Scenario: Conditioning discrete status signals (e.g., warhead arming, fin actuator feedback) before feeding into radiation-tolerant microcontrollers. IC Role / Device Role / Timing Role: SNJ54LS242FK serves as a dual-channel debounced interface IC, converting slow mechanical switch closures into clean TTL-level pulses. Use Value: Input hysteresis eliminates false triggers during vibration; ceramic FK package survives pyroshock events exceeding 10,000 g. |
| Spacecraft Telemetry Multiplexing | Nuclear Command & Control Logic |
Use Scenario: Buffering multiplexed sensor data streams (temperature, pressure, radiation) prior to serial encoding for downlink transmission. IC Role / Device Role / Timing Role: SNJ54LS242FK provides matched-delay buffering across two 4-bit channels to preserve time-aligned sampling integrity. Use Value: Guaranteed tPLH/tPHL ≤ 25 ns ensures sub-microsecond skew between parallel telemetry words - critical for frame synchronization. | Use Scenario: Interfacing hardened push-button panels with secure cryptographic modules in nuclear C2 systems requiring EMP resilience. IC Role / Device Role / Timing Role: SNJ54LS242FK functions as a fail-safe input conditioner, isolating human-interface signals from sensitive crypto ASICs. Use Value: Ceramic FK package and MIL-STD-883 screening provide verified EMP survivability; non-inverting logic preserves signal polarity for audit trails. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual 4-bit Schmitt buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SNJ54LS240FK | Inverting outputs instead of non-inverting; identical pinout, package, and military specs. | Requires logic inversion in downstream circuitry; unsuitable where signal polarity must be preserved end-to-end. | Select SNJ54LS240FK only if system-level logic design accommodates inverted outputs and no polarity-sensitive handshake protocols exist. |
| SNJ54LS241FK | Three-state outputs with enable control (1G, 2G); same Schmitt inputs and military rating. | Enables bus-sharing capability; adds control pin overhead but supports bidirectional or time-multiplexed data routing. | Choose SNJ54LS241FK when dynamic bus contention management is required, not just static buffering. |
Compared with SNJ54LS240FK and SNJ54LS241FK, the SNJ54LS242FK uniquely delivers non-inverting, non-three-state buffering - essential for polarity-critical interfaces like ARINC 429 receivers or analog comparator outputs where inversion would corrupt functional intent.
Availability
SNJ54LS242FK is available at Aetrix Electronics and suitable for avionics data bus interface, missile guidance signal conditioning, and spacecraft telemetry multiplexing requiring stable component supply across extended product lifecycles.
Supply support for SNJ54LS242FK 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 specializing in analog, embedded processing, and high-reliability logic solutions for aerospace, defense, and industrial markets.
The SNJ54LS242FK belongs to TI's military-grade 54LS logic family, designed specifically for mission-critical systems demanding guaranteed performance across extreme temperatures, radiation exposure, and mechanical stress.
FAQ
What is the maximum operating temperature for SNJ54LS242FK?
The SNJ54LS242FK is rated for continuous operation from –55°C to +125°C and is fully qualified to MIL-STD-883 Class V Space Level. This specification is verified through temperature cycling, thermal shock, and steady-state burn-in testing - ensuring reliability in orbital thermal vacuums and re-entry environments where the SNJ54LS242FK is deployed.
Does SNJ54LS242FK support three-state outputs?
No, the SNJ54LS242FK does not include three-state outputs or output enable controls. It provides fixed non-inverting TTL outputs only. For three-state functionality, consider the functionally similar SNJ54LS241FK, which shares the same package, Schmitt inputs, and military qualification but adds dual output-enable pins (1G and 2G).
Is SNJ54LS242FK pin-compatible with commercial 74LS242 devices?
No - while electrically compatible, the SNJ54LS242FK uses a 16-pin ceramic flatpack (FK) package with different lead pitch and mounting geometry than plastic DIP or SOIC packages used in commercial 74LS242 variants. PCB layout and assembly processes must be specifically designed for the FK footprint.
What is the input hysteresis value of SNJ54LS242FK?
The SNJ54LS242FK features Schmitt-trigger inputs with a typical hysteresis of 0.8 V, measured as the difference between VIT+ and VIT–. This value is confirmed across the full military temperature range and enables reliable operation with slow-rising signals such as those from thermistor-based comparators or relay contacts interfaced directly to the SNJ54LS242FK.
Can SNJ54LS242FK drive standard LS-TTL loads?
Yes, the SNJ54LS242FK is specified to drive up to 20 LS-TTL loads per output, with IOL = 8 mA and IOH = –0.4 mA at VCC = 5 V. This capability is validated per MIL-STD-883 test method 3015 and ensures compatibility with legacy LS-TTL systems without additional line drivers - a key requirement in retrofitting the SNJ54LS242FK into existing avionics hardware.
SNJ54LS242FK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Input Type:
- -
- Output Type:
- -
- Current - Output High, Low:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SNJ54LS242FK FAQ
1.How can I place an order for SNJ54LS242FK through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54LS242FK 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 SNJ54LS242FK reliable?
The price and inventory of SNJ54LS242FK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54LS242FK is usually 5 days.
3.What payment methods are accepted for SNJ54LS242FK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54LS242FK transactions.
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4.How is shipping managed for SNJ54LS242FK?
SNJ54LS242FK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54LS242FK 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 SNJ54LS242FK?
For technical support, including SNJ54LS242FK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54LS242FK requirements.
6.How does Aetrix verify that SNJ54LS242FK is sourced from the original manufacturer or authorized distributors?
All SNJ54LS242FK 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 SNJ54LS242FK meets industry standards.
7.What is the process for return or replacement of SNJ54LS242FK?
All SNJ54LS242FK units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54LS242FK, 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 SNJ54LS242FK part is unused and in its original packaging.
Return procedure for SNJ54LS242FK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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