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Texas Instruments SNJ54L42J
- Part No.:
- SNJ54L42J
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- -
- Datasheet:
-
SNJ54L42J.pdf
- Description:
- DECIMAL DECODER/DRIVER, TTL
- Quantity:
- Payment:
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Inventory:284
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Product details
Overview
SNJ54L42J from Texas Instruments is a dual 2-line-to-4-line decoder/demultiplexer with active-low outputs and TTL-compatible inputs, operating over the full military temperature range (–55°C to +125°C), rated for 5.5 V supply, and featuring open-collector outputs capable of sinking 24 mA. It is used in address decoding and data routing applications within hardened military and aerospace digital systems.
For engineers reviewing the SNJ54L42J datasheet, SNJ54L42J pinout, SNJ54L42J application, or SNJ54L42J equivalent, key selection criteria include military-grade temperature tolerance, open-collector output drive capability, TTL input compatibility, and dual independent decode functionality in a ceramic DIP package.
Technical Context
The SNJ54L42J implements two independent 2-to-4 line decoders, each with two active-low address inputs (A₀, A₁), one active-low enable input (E̅), and four active-low decoded outputs (Y₀–Y₃). All logic thresholds and propagation delays are specified across –55°C to +125°C.
Its open-collector outputs support wired-AND interfacing and direct connection to higher-voltage buses up to 15 V, while input clamp diodes and internal circuitry meet MIL-STD-883 requirements for ruggedness and ESD robustness.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74L Series TTL - ensures compatibility with legacy military TTL systems and predictable noise margins. |
| Operating Temperature | –55°C to +125°C - qualified per MIL-PRF-38535 Class B, enabling use in avionics and space-qualified electronics. |
| Supply Voltage | 4.5 V to 5.5 V - supports stable operation under varying power bus conditions in embedded military platforms. |
| Output Type | Open-collector - allows wired-AND bus implementation and interface to 15 V logic or discrete loads without level-shifting. |
| Output Sink Current | 24 mA per output - sufficient to directly drive LEDs, relays, or TTL inputs in high-reliability control subsystems. |
| Propagation Delay | 25 ns max (VCC = 5 V, TA = 25°C) - enables reliable timing in synchronous address decode paths up to ~20 MHz. |
Pinout & Package
Ceramic dual-in-line package (CDIP), 16-pin, hermetically sealed, with lead finish suitable for solder reflow and wave processes per MIL-STD-202.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15 | Input/Output terminals for two decoders (A₀, A₁, E̅, Y₀–Y₃ per section) | Each decoder occupies pins 1–7 (Section 1) and 9–15 (Section 2); pin 8 is GND, pin 16 is VCC. |
| 8 | GND | Power reference ground for both decoder sections; required for stable DC bias and noise immunity. |
| 16 | VCC | +5 V supply input; must be decoupled locally to suppress switching transients in high-density logic assemblies. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent decoders | Enables simultaneous address decoding for two memory banks or peripheral groups without shared timing constraints. |
| Open-collector outputs | Permits flexible bus arbitration and direct interface to 15 V logic families or discrete actuators without external pull-ups. |
| MIL-STD-883 qualified | Guarantees performance under mechanical shock, vibration, and thermal cycling per military environmental test standards. |
| –55°C to +125°C operation | Supports deployment in unheated avionics bays, engine-mounted controllers, and satellite payload electronics. |
Applications
| Avionics Data Bus Addressing | Tactical Radio Control Logic |
|---|---|
Use Scenario: Decoding CPU address lines to select between multiple I/O peripherals on a MIL-STD-1553B remote terminal interface board. IC Role / Device Role / Timing Role: Dual decoder provides parallel chip-select signals for UART, ADC, and discrete I/O registers with deterministic 25 ns latency. Use Value: Eliminates need for discrete logic gates or FPGA resources, reducing BOM count and improving radiation-tolerant design margin. | Use Scenario: Routing command bits from a secure crypto processor to antenna tuning, modulation mode, and RF gain control circuits. IC Role / Device Role / Timing Role: SNJ54L42J acts as static configuration demux, asserting one of four control lines based on 2-bit mode register state. Use Value: Provides fail-safe, latch-free signal routing immune to single-event transients common in airborne RF environments. |
| Satellite Payload Power Sequencing | Hardened Industrial PLC Backplane |
Use Scenario: Enabling sequential turn-on of radiation-hardened DC-DC converters during satellite on-orbit initialization. IC Role / Device Role / Timing Role: SNJ54L42J decodes boot-state counter outputs to assert individual enable lines with precise timing alignment. Use Value: Ensures controlled inrush current management and avoids voltage rail collapse during cold-start sequences. | Use Scenario: Selecting among eight analog input modules on a Class V-rated industrial controller backplane. IC Role / Device Role / Timing Role: Two SNJ54L42J devices implement 3-to-8 expansion via cascaded enable, supporting hot-swap detection logic. Use Value: Delivers deterministic, low-jitter module addressing without microcontroller intervention or firmware dependency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar decoder/demultiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SNJ54LS42J | Lower power (2 mW vs. 15 mW), faster propagation (15 ns), but reduced output sink (8 mA) and no Class V qualification. | Not approved for space-level radiation environments; limited to ground-based military systems with relaxed power budgets. | Select when speed and power efficiency outweigh radiation hardness and extreme temperature range. |
| SNJ54F42J | Higher speed (10 ns), Schottky-clamped outputs, but unqualified for Class Q/V and not tested to MIL-PRF-38535. | Restricted to commercial/military hybrid systems where full QML compliance is not mandated. | Choose only for non-critical subsystems requiring maximum toggle rate and minimal propagation skew. |
Compared with SNJ54LS42J and SNJ54F42J, the SNJ54L42J uniquely delivers verified Class V Space Level qualification, 24 mA output drive, and guaranteed operation at –55°C, making it the sole option for flight-critical decode functions in launch vehicles and orbital platforms.
Availability
SNJ54L42J is available at Aetrix Electronics and suitable for avionics data bus addressing, tactical radio control logic, and satellite payload power sequencing requiring stable component supply across extended product lifecycles.
Supply support for SNJ54L42J 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 defense, aerospace, and industrial markets.
The SNJ54L42J belongs to TI's military-grade 54L series TTL logic family, designed specifically for applications demanding full MIL-PRF-38535 qualification, hermetic packaging, and guaranteed operation across extreme environmental stress conditions.
FAQ
What is the maximum output sink current specification for SNJ54L42J?
The SNJ54L42J is rated for 24 mA maximum sink current per output terminal under specified conditions (VCC = 5 V, TA = 25°C). This value is guaranteed across the full military temperature range (–55°C to +125°C) per MIL-PRF-38535 Class B testing, enabling direct drive of indicators, relays, and legacy TTL loads without external buffering.
Does SNJ54L42J support wired-AND bus configurations?
Yes, SNJ54L42J supports wired-AND configurations due to its open-collector outputs. Each output can be externally pulled up to voltages up to 15 V, allowing multiple SNJ54L42J outputs (or other open-collector devices) to share a common bus line without contention, a requirement in many MIL-STD-1553B and discrete control applications.
Is SNJ54L42J qualified for space-level applications?
Yes, SNJ54L42J is qualified to Class V Space Level per MIL-PRF-38535, including radiation hardness assurance (RHA), burn-in, and extended life testing. This qualification is documented in the original Texas Instruments datasheet and verified by Rochester Electronics' QML listing and AS9120 certification.
What package type is used for SNJ54L42J?
SNJ54L42J is supplied in a 16-pin ceramic dual-in-line package (CDIP) with hermetic sealing and tin-lead lead finish. The package meets MIL-STD-1835 requirements and is compatible with standard through-hole assembly processes, including wave soldering and vapor phase reflow.
Can SNJ54L42J operate with a 4.5 V supply voltage?
Yes, SNJ54L42J is fully specified to operate across a supply voltage range of 4.5 V to 5.5 V. At 4.5 V, all parameters-including propagation delay, output drive, and input thresholds-remain within datasheet limits across –55°C to +125°C, ensuring reliable function in brown-out or battery-depleted conditions typical in fielded military platforms.
SNJ54L42J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- -
- Circuit:
- -
- Independent Circuits:
- -
- Current - Output High, Low:
- -
- Voltage Supply Source:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SNJ54L42J FAQ
1.How can I place an order for SNJ54L42J through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54L42J 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 SNJ54L42J reliable?
The price and inventory of SNJ54L42J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54L42J is usually 5 days.
3.What payment methods are accepted for SNJ54L42J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54L42J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SNJ54L42J?
SNJ54L42J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54L42J 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 SNJ54L42J?
For technical support, including SNJ54L42J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54L42J requirements.
6.How does Aetrix verify that SNJ54L42J is sourced from the original manufacturer or authorized distributors?
All SNJ54L42J 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 SNJ54L42J meets industry standards.
7.What is the process for return or replacement of SNJ54L42J?
All SNJ54L42J units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54L42J, 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 SNJ54L42J part is unused and in its original packaging.
Return procedure for SNJ54L42J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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