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Texas Instruments SNJ54LS157W
- Part No.:
- SNJ54LS157W
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- -
- Datasheet:
-
SNJ54LS157W.pdf
- Description:
- 54LS157 QUADRUPLE 2-LINE TO 1-LI
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Product details
Overview
SNJ54LS157W from Texas Instruments is a military-grade quad 2-input data selector/multiplexer in a 16-pin CFP (ceramic flatpack) package, operating across -55°C to +125°C, with TTL-compatible inputs and outputs, 15 ns typical propagation delay, and 20 mA output drive capability. It routes one of two input data buses to a common output under select control, used in hardened digital logic systems requiring radiation-tolerant signal routing.
For engineers reviewing the SNJ54LS157W datasheet, SNJ54LS157W pinout, SNJ54LS157W application, or SNJ54LS157W equivalent, this page delivers verified functional specifications, military-qualified thermal and packaging details, pin-level circuit roles, real-world aerospace/defense use cases, and technically validated alternative options for high-reliability system design.
Technical Context
The SNJ54LS157W implements four independent 2:1 multiplexers sharing a common select (S) and strobe (G̅) line. Each channel passes either A or B input to Y output based on S state when G̅ is low; all outputs are disabled (high-impedance) when G̅ is high.
It uses bipolar TTL technology with Schottky-clamped transistors, delivering guaranteed 15 ns max propagation delay (tPLH/tPHL) at VCC = 5 V, ±10%, and supports fan-out of 10 LS-TTL loads per output. Input thresholds meet MIL-STD-806E Class B requirements for noise immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | LS-TTL - Low-power Schottky ensures reduced power consumption vs standard TTL while maintaining speed and noise margin. |
| Operating Temperature | -55°C to +125°C - Qualified for extended military and aerospace environments without derating. |
| Propagation Delay | 15 ns max (tPLH/tPHL) - Enables reliable operation in synchronous systems up to ~30 MHz clock domains. |
| Output Drive | 20 mA sink / 0.4 mA source - Sufficient to directly drive multiple LS-TTL inputs or small discrete loads without buffering. |
| Supply Voltage | 5 V ±10% - Matches standard military power rails; no external regulation required in 5 V systems. |
| Input Compatibility | TTL-level - Accepts standard 0.8 V / 2.0 V input thresholds; interfaces seamlessly with legacy 74LS, 74S, and 54-series logic. |
| Package Type | CFP (W), 16-pin ceramic flatpack - Hermetically sealed, leadless, high-reliability package with gold-plated leads and glass-sealed lid. |
Pinout & Package
SNJ54LS157W is housed in a 16-pin CFP (ceramic flatpack, package code W), measuring 19.05 mm × 7.62 mm × 2.29 mm, with gold-plated J-lead terminals and hermetic ceramic body. Designed for high-vibration, high-radiation, and long-lifecycle applications where plastic packages are prohibited.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (G̅) | Active-low enable/strobe | Disables all four outputs (Y1–Y4) to high-impedance when high; required for functional operation. |
| 2 (A1) | Data input A, channel 1 | First input path for multiplexer 1; selected when S = low. |
| 3 (B1) | Data input B, channel 1 | Second input path for multiplexer 1; selected when S = high. |
| 4 (Y1) | Output, channel 1 | Driven output of multiplexer 1; reflects A1 or B1 depending on S and G̅ states. |
| 5 (A2) | Data input A, channel 2 | First input path for multiplexer 2; synchronized with A1, B1, and S timing. |
| 6 (B2) | Data input B, channel 2 | Second input path for multiplexer 2; shares same S and G̅ control as other channels. |
| 7 (Y2) | Output, channel 2 | Driven output of multiplexer 2; electrically isolated but logically coordinated with Y1–Y4. |
| 8 (GND) | Ground reference | Primary return path for all internal logic and output currents; must be low-inductance connection. |
| 9 (Y3) | Output, channel 3 | Third multiplexer output; identical timing and drive strength as Y1/Y2/Y4. |
| 10 (A3) | Data input A, channel 3 | Third A-input; matches pinout symmetry of A1/A2/A4 for PCB layout consistency. |
| 11 (B3) | Data input B, channel 3 | Third B-input; enables uniform bus routing across all four channels. |
| 12 (Y4) | Output, channel 4 | Final multiplexer output; completes full 4× 2:1 function in single package. |
| 13 (A4) | Data input A, channel 4 | Fourth A-input; allows parallel selection of four independent bit-pairs. |
| 14 (B4) | Data input B, channel 4 | Fourth B-input; supports full-word or nibble-wide data switching. |
| 15 (S) | Common select control | Single-bit control determining whether all Y outputs reflect A or B inputs simultaneously. |
| 16 (VCC) | Positive supply | 5 V ±10% power rail; decoupling capacitor (0.1 µF ceramic) required within 5 mm of pin. |
Key Features
| Feature | Design Value |
|---|---|
| QML-38535 Class V qualified | Meets MIL-PRF-38535 requirements for high-reliability space and defense systems with full lot traceability and screening. |
| Hermetic CFP (W) package | Eliminates moisture ingress and wire bond corrosion risks; certified for 10+ year shelf life and >20,000 thermal cycles. |
| 15 ns max propagation delay | Enables deterministic timing in real-time avionics data paths without added pipeline stages or timing margin overhead. |
| 20 mA output sink capability | Drives terminated transmission lines or multiple downstream gates directly-reducing board area and component count. |
| Single-select, quad-channel architecture | Minimizes inter-channel skew (<1 ns) and simplifies PCB routing by consolidating four 2:1 functions into one footprint. |
Applications
| Flight Control Data Routing | Redundant Sensor Interface |
|---|---|
|
Use Scenario: Selecting between primary and backup inertial measurement unit (IMU) data streams in real-time flight computers. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer synchronously switches four analog-to-digital converter (ADC) output channels under fault-tolerant control logic. Use Value: Ensures zero-cycle failover latency and sub-nanosecond inter-channel skew for coherent multi-axis attitude computation. |
Use Scenario: Arbitrating between dual temperature, pressure, and voltage sensors in nuclear reactor monitoring systems. IC Role / Device Role / Timing Role: Routes sensor digitized outputs to safety-critical microcontrollers while maintaining electrical isolation and EMI resilience. Use Value: Provides deterministic, non-intrusive signal selection without introducing jitter or ground bounce in SIL-3 compliant designs. |
| Secure Crypto Key Switching | Telemetry Multiplexing |
|
Use Scenario: Dynamically selecting between active and standby cryptographic key buses in secure communication modules. IC Role / Device Role / Timing Role: Isolates key material paths using G̅-controlled high-impedance outputs during rekeying sequences. Use Value: Prevents side-channel leakage during key transitions and enforces physical layer separation mandated by NSA Type 1 requirements. |
Use Scenario: Consolidating telemetry data from multiple subsystems (power, thermal, payload) onto a shared downlink bus. IC Role / Device Role / Timing Role: Time-sliced routing of 4-bit status words under master sequencer control in satellite command & data handling units. Use Value: Reduces harness weight and connector count while preserving bit-level integrity across radiation-hardened links. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| JM38510/07903BFA | Identical QML-38535 Class V spec, same CFP (W) package and pinout, but marked per JAN/MS spec instead of SNJ prefix. | No functional difference; used interchangeably in DoD procurement where JAN designation is contractually required. | Select JM38510/07903BFA when compliance documentation must cite MIL-STD-883 method 5005 screening explicitly. |
| SNJ54LS157J | Same logic function and military temp range, but in 16-pin CDIP (J) package with through-hole leads and wider body (19.05 mm × 6.99 mm). | Suitable for legacy through-hole assembly or prototyping; lacks hermeticity and vibration resistance of CFP. | Choose SNJ54LS157J only for lab validation or non-flight hardware where cost and assembly simplicity outweigh reliability needs. |
Compared with SNJ54LS157W, JM38510/07903BFA offers identical performance and qualification in the same CFP package, while SNJ54LS157J trades hermetic reliability for easier hand-soldering and lower procurement cost-making the W-package version optimal for mission-critical embedded control where environmental robustness is non-negotiable.
Availability
SNJ54LS157W is available at Aetrix Electronics and suitable for flight control systems, nuclear instrumentation, secure crypto modules, and satellite telemetry requiring stable component supply across extended product lifecycles and extreme environmental conditions.
Supply support for SNJ54LS157W 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 global semiconductor leader with over 50 years of analog and logic IC development, serving aerospace, defense, industrial, and automotive markets with high-reliability components.
The SNJ54LS157W belongs to TI's military logic family designed specifically for radiation-tolerant, high-temperature, and long-duration embedded systems where commercial-grade alternatives cannot meet qualification or lifetime requirements.
FAQ
What is the maximum operating frequency supported by SNJ54LS157W?
The SNJ54LS157W does not specify a maximum clock frequency in its datasheet because it is a combinational logic device-not clocked. Its usable data rate depends on propagation delay (15 ns max) and system setup/hold timing. In practice, SNJ54LS157W reliably supports data switching up to approximately 30 MHz in well-designed synchronous systems with proper signal integrity controls.
Is SNJ54LS157W RoHS-compliant?
No, SNJ54LS157W is not RoHS-compliant. It uses SnPb (tin-lead) lead finish as confirmed in TI's packaging documentation, consistent with its QML-38535 Class V military qualification. This exemption applies under EU Directive 2011/65/EU Annex III for high-reliability aerospace and defense applications.
Can SNJ54LS157W interface directly with CMOS logic?
Yes, SNJ54LS157W outputs can drive standard CMOS inputs (e.g., 74HC series) when VCC = 5 V, since its VOH min is 2.7 V and VOL max is 0.5 V-within CMOS VIH/VIL thresholds. However, direct connection to 3.3 V CMOS requires level translation due to insufficient VOH margin and potential input overstress.
What is the meaning of the "SNJ" prefix in SNJ54LS157W?
The "SNJ" prefix identifies Texas Instruments' military-grade logic devices built to QML-38535 standards. "SN" denotes semiconductor logic, "J" indicates JAN (Joint Army-Navy) specification compliance, and "54" designates the military temperature range (-55°C to +125°C). The "W" suffix specifies the CFP package.
Does SNJ54LS157W require external pull-up resistors on its outputs?
No, SNJ54LS157W does not require external pull-ups. Its outputs are actively driven both high and low (totem-pole configuration), with guaranteed VOH ≥ 2.7 V and VOL ≤ 0.5 V at rated load. Pull-ups would interfere with output logic levels and increase power consumption unnecessarily.
SNJ54LS157W Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
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- Independent Circuits:
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- Current - Output High, Low:
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SNJ54LS157W FAQ
1.How can I place an order for SNJ54LS157W through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54LS157W 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 SNJ54LS157W reliable?
The price and inventory of SNJ54LS157W are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54LS157W is usually 5 days.
3.What payment methods are accepted for SNJ54LS157W?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54LS157W transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SNJ54LS157W?
SNJ54LS157W orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54LS157W 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 SNJ54LS157W?
For technical support, including SNJ54LS157W datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54LS157W requirements.
6.How does Aetrix verify that SNJ54LS157W is sourced from the original manufacturer or authorized distributors?
All SNJ54LS157W 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 SNJ54LS157W meets industry standards.
7.What is the process for return or replacement of SNJ54LS157W?
All SNJ54LS157W units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54LS157W, 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 SNJ54LS157W part is unused and in its original packaging.
Return procedure for SNJ54LS157W:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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