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Texas Instruments SNJ54LS155AJ
- Part No.:
- SNJ54LS155AJ
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- -
- Datasheet:
-
SNJ54LS155AJ.pdf
- Description:
- 54LS155A DUAL 2-LINE TO 4-LINE D
- Quantity:
- Payment:
- Shipping:
Inventory:227
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Product details
Overview
SNJ54LS155AJ from Texas Instruments is a dual 2-line-to-4-line decoder/demultiplexer in a hermetically sealed ceramic dual-in-line package (CDIP), operating across –55°C to +125°C. It features TTL-compatible inputs, active-low enable control (G̅), and four active-low decoded outputs per section. Used in military-grade address decoding and data routing within avionics and ruggedized digital systems.
For engineers reviewing the SNJ54LS155AJ datasheet, SNJ54LS155AJ pinout, SNJ54LS155AJ application, or SNJ54LS155AJ equivalent, key selection considerations include its military temperature range, SNPB lead finish, CDIP-16 package, dual independent decode sections, and compatibility with legacy TTL logic families.
Technical Context
The SNJ54LS155AJ integrates two identical 2-to-4 line decoders on a single die, each with separate address inputs (A₀, A₁) and individual active-low enable (G̅₁, G̅₂). Each decoder drives four active-low outputs (Y₀–Y₃), enabling independent channel selection without inter-section crosstalk.
It uses low-power Schottky (LS) TTL technology, delivering propagation delays of 22 ns (max) at VCC = 5 V and IOL = 8 mA, with input clamp diodes for transient protection and guaranteed fan-out of 20 LS-TTL loads per output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | Dual 2-line-to-4-line decoder/demultiplexer with independent enables |
| Logic Family | LS-TTL - ensures compatibility with 74LS series and reduced power vs standard TTL |
| Supply Voltage | 4.5 V to 5.5 V - supports stable operation under regulated 5 V military power rails |
| Propagation Delay | 22 ns max (tPLH/tPHL) - enables reliable timing in synchronous 20 MHz-class control logic |
| Operating Temperature | –55°C to +125°C - qualified for extended-range military and aerospace environments |
| Package | Ceramic DIP (CDIP), 16-pin - hermetic seal prevents moisture ingress and ensures long-term reliability |
| Lead Finish | SnPb (SNPB) - compatible with legacy wave-solder processes and exempt from RoHS |
Pinout & Package
Ceramic Dual-In-Line Package (CDIP), 16-pin, 0.300-inch wide body, hermetically sealed with glass-metal lid and tin-lead leads. Designed for through-hole mounting and high-reliability board assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15 | G̅₁, G̅₂ (Active-Low Enables) | Independent enable inputs per decoder section; both must be LOW for corresponding outputs to respond |
| 2, 3, 5, 6 | A₀₁, A₁₁, A₀₂, A₁₂ (Address Inputs) | Two-bit binary address inputs per section; determine which of four outputs goes LOW |
| 4, 7, 10, 13 | Y₀₁–Y₃₁, Y₀₂–Y₃₂ (Active-Low Outputs) | Four decoded active-low outputs per section; only one asserted per valid address+enable combination |
| 8 | GND | Power ground reference for all logic and output stages |
| 16 | VCC | +5 V supply rail; powers internal gates and output drivers |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent decode sections | Enables simultaneous, isolated address decoding for two peripheral groups without shared control logic |
| Active-low enable and outputs | Simplifies interface with common cathode displays, NAND-based control trees, and legacy bus architectures |
| Low-power Schottky (LS) design | Reduces typical power dissipation to 19 mW per section versus 48 mW for standard 74155, easing thermal management |
| Military-grade temperature range | Validated operation from –55°C to +125°C supports deployment in uncontrolled environmental enclosures |
| Hermetic CDIP packaging | Prevents humidity-induced parameter drift and corrosion, critical for 20+ year field life in defense systems |
Applications
| Avionics Data Bus Decoding | Secure Communication Module Addressing |
|---|---|
|
Use Scenario: Selecting one of four ARINC 429 receiver buffers based on command word address bits. IC Role / Device Role / Timing Role: Dual decoder routes command signals to dedicated receive channels while maintaining isolation between redundant data paths. Use Value: Eliminates need for discrete gate logic, reduces PCB area by 35%, and guarantees deterministic <22 ns decode latency across flight temperature extremes. |
Use Scenario: Enabling specific encryption engine registers during secure boot sequence in Type 1 crypto hardware. IC Role / Device Role / Timing Role: Provides glitch-free, synchronized register selection using dual enables tied to state machine outputs. Use Value: Prevents partial register activation during power-up transients, meeting NSA Class A timing integrity requirements. |
| Tactical Radio Channel Switching | Ruggedized Test Equipment Signal Routing |
|
Use Scenario: Routing IF signal paths among four bandpass filters in a software-defined radio front-end. IC Role / Device Role / Timing Role: Decoder controls analog switch enables via open-collector-compatible outputs driving MOSFET gates. Use Value: Supports fast channel switching (<50 ns setup/hold margin) while surviving MIL-STD-810G shock/vibe profiles. |
Use Scenario: Configuring stimulus/sense paths in automated test equipment for missile guidance subsystems. IC Role / Device Role / Timing Role: Acts as static configuration selector for multiplexed analog and digital test interfaces. Use Value: Maintains signal integrity over 10⁶+ thermal cycles due to hermetic CDIP construction and LS-TTL noise immunity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual 2-to-4 decoder applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS155AN | Commercial temperature range (0°C to +70°C); plastic DIP package; RoHS-compliant NiPdAu finish | Approved for industrial benchtop equipment but not qualified for airborne or vehicle-mounted deployments | Select when cost, reflow compatibility, or commercial lifecycle support outweighs extended temperature and hermeticity needs. |
| SNJ54LS156J | Same CDIP-16 package and military temp range, but includes complementary (active-high) outputs alongside active-low | Required where mixed-output polarity is needed - e.g., driving both LED indicators and transistor switches simultaneously | Choose only if system-level logic demands concurrent active-high and active-low decode outputs; otherwise SNJ54LS155AJ offers lower part count. |
Compared with SN74LS155AN, SNJ54LS155AJ provides guaranteed operation at extreme temperatures and hermetic reliability, while SNJ54LS156J adds output polarity flexibility at the cost of increased layout complexity and no improvement in timing or power.
Availability
SNJ54LS155AJ is available at Aetrix Electronics and suitable for avionics data routing, secure communications addressing, and tactical radio channel switching requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SNJ54LS155AJ 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 SNJ54LS155AJ belongs to TI's military-grade 54LS logic family, designed specifically for applications demanding assured performance under extreme environmental stress and long-term obsolescence resilience.
FAQ
What is the maximum clock frequency supported by SNJ54LS155AJ?
The SNJ54LS155AJ is a combinational logic device without an internal clock; it responds asynchronously to input changes. Its usable switching rate is limited by propagation delay (22 ns max) and system-level setup/hold timing. In practice, SNJ54LS155AJ reliably supports address decode operations up to 20 MHz in well-designed TTL systems with proper termination and layout.
Does SNJ54LS155AJ support mixed-voltage interfacing, such as 3.3 V microcontrollers?
No - SNJ54LS155AJ requires a 4.5 V to 5.5 V VCC supply and has TTL input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V). Direct connection to 3.3 V logic may result in marginal or non-functional high-level recognition. Level-shifting circuitry or a compatible 5 V MCU is required for reliable interfacing with SNJ54LS155AJ.
Is SNJ54LS155AJ pin-compatible with SN74LS155A?
Yes - SNJ54LS155AJ and SN74LS155A share identical pinout, logic function, and electrical behavior. The difference lies solely in temperature rating (–55°C to +125°C vs 0°C to +70°C) and package construction (hermetic CDIP vs plastic PDIP). No PCB changes are required when substituting SNJ54LS155AJ into designs originally using SN74LS155A, provided thermal and reliability requirements align.
Can SNJ54LS155AJ drive LEDs directly?
Yes - each active-low output can sink up to 8 mA (IOL) at VOL ≤ 0.5 V, sufficient to drive standard indicator LEDs with appropriate current-limiting resistors (e.g., 470 Ω @ 5 V). However, for higher-current loads or multiplexed displays, external buffer transistors are recommended to maintain output voltage compliance and avoid exceeding total package power limits.
Where can I find the official SNJ54LS155AJ datasheet and package drawings?
The official SNJ54LS155AJ datasheet (SDLS057) and mechanical drawings are published by Texas Instruments and available for download at ti.com under part number SNJ54LS155AJ. The document includes detailed DC/AC specifications, timing diagrams, truth tables, recommended operating conditions, and CDIP-16 package dimensions with land patterns and stencil guidelines.
SNJ54LS155AJ 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:
- -
SNJ54LS155AJ FAQ
1.How can I place an order for SNJ54LS155AJ through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54LS155AJ 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 SNJ54LS155AJ reliable?
The price and inventory of SNJ54LS155AJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54LS155AJ is usually 5 days.
3.What payment methods are accepted for SNJ54LS155AJ?
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4.How is shipping managed for SNJ54LS155AJ?
SNJ54LS155AJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54LS155AJ 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 SNJ54LS155AJ?
For technical support, including SNJ54LS155AJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54LS155AJ requirements.
6.How does Aetrix verify that SNJ54LS155AJ is sourced from the original manufacturer or authorized distributors?
All SNJ54LS155AJ 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 SNJ54LS155AJ meets industry standards.
7.What is the process for return or replacement of SNJ54LS155AJ?
All SNJ54LS155AJ units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54LS155AJ, 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 SNJ54LS155AJ part is unused and in its original packaging.
Return procedure for SNJ54LS155AJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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