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Texas Instruments SNJ54LS257BW
- Part No.:
- SNJ54LS257BW
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-CFlatPack
- Datasheet:
-
SNJ54LS257BW.pdf
- Description:
- QUADRUPLE 2-LINE TO 1-LINE DATA
- Quantity:
- Payment:
- Shipping:
Inventory:1,298
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Product details
Overview
SNJ54LS257BW from Texas Instruments is a military-grade quadruple 2-line to 1-line data selector/multiplexer in CFP (W) package with 16 pins, operating across –55°C to +125°C. It features TTL-compatible inputs and outputs, low propagation delay (22 ns typical), complementary enable control (G̅), and independent 2:1 selection per channel for digital signal routing in avionics and hardened logic systems.
For engineers reviewing the SNJ54LS257BW datasheet, SNJ54LS257BW pinout, SNJ54LS257BW application, or SNJ54LS257BW equivalent, this device supports high-reliability multiplexing in legacy military computing, test instrumentation, and radiation-tolerant control logic where extended temperature range and SNPB lead finish are required.
Technical Context
The SNJ54LS257BW implements four independent 2:1 multiplexer channels sharing a common active-low enable (G̅) input. Each channel selects between two data inputs (A and B) based on a single select line (S), producing one output (Y). All inputs and outputs are TTL-compatible with guaranteed noise margins and standard LS logic thresholds.
It belongs to the SN54LS family, designed for military applications with full screening per MIL-PRF-38535 Class B requirements. Its CFP (W) ceramic flatpack package provides hermetic sealing, thermal stability, and mechanical robustness essential for aerospace and defense deployments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | Quadruple 2-line to 1-line data selector/multiplexer - routes one of two digital inputs per channel to a shared output under select control. |
| Supply Voltage | VCC = 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL systems and stable operation under supply variation. |
| Propagation Delay | 22 ns max (tPLH/tPHL at VCC = 5 V, TA = 25°C) - enables reliable timing in synchronous logic up to ~20 MHz clock domains. |
| Operating Temperature | –55°C to +125°C - qualified for extreme-environment deployment in airborne, spaceborne, and ground vehicle control systems. |
| Input Compatibility | TTL-level inputs (VIH ≥ 2.0 V, VIL ≤ 0.8 V) - interoperable with standard LS, ALS, and F series logic without level shifting. |
| Output Drive | IOL = 24 mA / IOH = –0.4 mA (min) - sufficient to drive 10 LS-TTL loads directly, supporting fanout-critical backplane designs. |
Pinout & Package
SNJ54LS257BW uses a 16-pin CFP (W) ceramic flatpack package: 10.4 mm × 7.4 mm body, 1.27 mm lead pitch, hermetically sealed, with SNPB (tin-lead) finish and no moisture sensitivity rating (N/A).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 5, 9, 10, 12, 13 | Data Inputs (A0–A3, B0–B3) | Eight independent data inputs - A0/B0 feed channel 0, A1/B1 feed channel 1, etc.; TTL-compatible voltage thresholds. |
| 3, 6, 11, 14 | Outputs (Y0–Y3) | Four buffered, inverted-logic outputs - each Yn reflects selected input (An or Bn) when G̅ = LOW and S matches selection state. |
| 7 | GND | Ground reference for all internal logic and I/O - must be connected to system ground plane for noise immunity and DC bias stability. |
| 8 | VCC | Positive supply rail - requires clean 5 V ±5% with local 0.1 µF ceramic decoupling adjacent to pin. |
| 15 | G̅ | Active-low global enable - all outputs go HIGH-Z when G̅ = HIGH; enables bus-sharing and power-gating in multi-device systems. |
| 16 | S | Common select line - determines whether A or B input is routed to each Y output (S = LOW → A selected; S = HIGH → B selected). |
Key Features
| Feature | Design Value |
|---|---|
| Quad independent 2:1 mux channels | Enables simultaneous routing of four separate data pairs using only one select line and one enable - reduces control logic overhead in parallel bus architectures. |
| Military temperature range (–55°C to +125°C) | Validated operation across full MIL-STD-883 temperature extremes - eliminates derating concerns in uncontrolled environmental enclosures. |
| Hermetic CFP (W) package | Provides long-term reliability in high-humidity, high-vibration, or corrosive environments where plastic packages risk delamination or leakage. |
| Standard TTL interface levels | Direct drop-in replacement for legacy 74LS257-based designs without redesigning surrounding logic or adjusting termination schemes. |
| Low-power Schottky (LS) technology | Delivers 2× speed vs. standard TTL with <1/3 the power consumption - critical for thermally constrained avionics chassis and battery-backed systems. |
Applications
| Avionics Data Bus Switching | Test Equipment Signal Routing |
|---|---|
|
Use Scenario: Selecting between primary and backup sensor data streams in flight control computers during redundancy arbitration. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer enabling real-time failover switching with sub-25 ns latency and deterministic timing behavior. Use Value: Ensures continuous data path integrity without software intervention, meeting DO-254 Level A hardware design assurance requirements. |
Use Scenario: Routing DUT signals between multiple measurement instruments (oscilloscope, logic analyzer, DMM) in automated test fixtures. IC Role / Device Role / Timing Role: Hardware-controlled signal selector allowing instrument reconfiguration via FPGA GPIO without relays or manual cabling. Use Value: Eliminates mechanical relay wear and contact resistance drift, improving test repeatability and fixture MTBF. |
| Hardened Industrial PLC I/O | Radiation-Tolerant Telemetry |
|
Use Scenario: Multiplexing analog-to-digital converter outputs from redundant sensor arrays in oilfield downhole controllers exposed to thermal cycling. IC Role / Device Role / Timing Role: Digital front-end selector synchronizing with ADC sampling clocks while maintaining isolation between channel groups. Use Value: Supports dual-channel voting logic and hot-swap diagnostics without introducing jitter or metastability in safety-critical loops. |
Use Scenario: Consolidating telemetry packets from multiple radiation-hardened microcontrollers onto a single serial uplink in satellite subsystems. IC Role / Device Role / Timing Role: Low-jitter, latch-free data combiner ensuring bit-aligned packet framing prior to RF modulation. Use Value: Maintains end-to-end timing coherence across distributed nodes, preserving time-of-arrival accuracy for orbit determination. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| JM38510/07906BFA | Identical function, pinout, and CFP (W) package; same –55°C to +125°C range but qualified to MIL-PRF-38535 Class V (higher screen level). | Required for programs mandating Class V screening (e.g., strategic missile guidance); not needed for general Class B avionics. | Select JM38510/07906BFA only if Class V conformance documentation (e.g., QML-V certificate) is contractually required. |
| SNJ54LS257BJ | Same logic and specs, but in CDIP (J) ceramic DIP package - larger footprint (19.05 mm × 7.62 mm), through-hole mounting, identical SNPB finish. | Better suited for prototyping, manual assembly, or legacy board layouts with DIP sockets; less suitable for high-density surface-mount designs. | Choose SNJ54LS257BJ for hand-soldered test benches or upgrades of existing DIP-based systems where CFP rework is impractical. |
Compared with JM38510/07906BFA and SNJ54LS257BJ, SNJ54LS257BW offers optimal balance of compact surface-mount packaging, Class B qualification, and proven field reliability - making it the preferred choice for new high-density military PCB designs requiring CFP integration.
Availability
SNJ54LS257BW is available at Aetrix Electronics and suitable for avionics data switching, test equipment signal routing, and hardened industrial PLC I/O requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SNJ54LS257BW 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 leader founded in 1930, specializing in analog, embedded processing, and high-reliability logic solutions for aerospace, defense, and industrial markets.
The SNJ54LS257BW belongs to TI's military logic portfolio, engineered specifically for mission-critical systems demanding guaranteed performance across extreme temperatures, radiation environments, and long service intervals.
FAQ
What is the maximum clock frequency supported by SNJ54LS257BW?
The SNJ54LS257BW does not operate on a clock; it is a combinational logic device. Its usable data rate depends on propagation delay (22 ns max) and system setup/hold timing. In practice, it reliably handles asynchronous data switching up to ~20 MHz edge rates when interfaced with LS-family drivers and loads.
Is SNJ54LS257BW RoHS compliant?
No, SNJ54LS257BW uses SNPB (tin-lead) lead finish and is explicitly marked "No" for RoHS compliance in TI's packaging documentation. It is intended for military/aerospace applications where leaded finishes are permitted and preferred for solder joint reliability under thermal cycling.
Can SNJ54LS257BW replace SN74LS257BN in a commercial design?
SNJ54LS257BW is not a direct replacement for SN74LS257BN due to differing temperature range (–55°C to +125°C vs. 0°C to +70°C), package (CFP vs. PDIP), and qualification level (military vs. commercial). Electrical specs match, but thermal and mechanical compatibility must be verified per application.
What is the meaning of the "G̅" pin on SNJ54LS257BW?
The G̅ pin is an active-low global enable input. When G̅ = LOW, the device operates normally, routing selected inputs to outputs. When G̅ = HIGH, all four Y outputs enter high-impedance (Hi-Z) state - enabling bus sharing and preventing contention in multi-driver configurations.
Does SNJ54LS257BW require external pull-up resistors on its outputs?
No. SNJ54LS257BW has totem-pole TTL outputs capable of actively driving both HIGH and LOW states. Pull-up resistors are unnecessary unless interfacing with open-collector systems or implementing wired-OR logic - which is not typical for this device's intended use cases.
SNJ54LS257BW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 54LS
- Package/Case:
- 16-CFlatPack
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Data Selector/Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 1mA, 12mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-CFP
SNJ54LS257BW FAQ
1.How can I place an order for SNJ54LS257BW through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54LS257BW 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 SNJ54LS257BW reliable?
The price and inventory of SNJ54LS257BW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54LS257BW is usually 5 days.
3.What payment methods are accepted for SNJ54LS257BW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54LS257BW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SNJ54LS257BW?
SNJ54LS257BW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54LS257BW 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 SNJ54LS257BW?
For technical support, including SNJ54LS257BW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54LS257BW requirements.
6.How does Aetrix verify that SNJ54LS257BW is sourced from the original manufacturer or authorized distributors?
All SNJ54LS257BW 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 SNJ54LS257BW meets industry standards.
7.What is the process for return or replacement of SNJ54LS257BW?
All SNJ54LS257BW units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54LS257BW, 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 SNJ54LS257BW part is unused and in its original packaging.
Return procedure for SNJ54LS257BW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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