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Home > Products > Integrated Circuits (ICs) > Logic > Signal Switches, Multiplexers, Decoders

Texas Instruments SNJ54S157FK

Name: SNJ54S157FK
Brand: Texas Instruments
SKU: SNJ54S157FK
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SNJ54S157FK

Manufacturer:: Texas Instruments

Category:: Signal Switches, Multiplexers, Decoders

Package:: -

Datasheet:: SNJ54S157FK.pdf

Description:: 54S157 QUADRUPLE 2-LINE TO 1-LIN

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SNJ54S157FK from Texas Instruments is a high-speed TTL quad 2-line-to-1-line data selector/multiplexer in hermetically sealed LCCC (FK) package with 20 leads, operating across –55°C to +125°C, featuring complementary enable control and guaranteed propagation delay of ≤10 ns at V_CC = 5V, used in military-grade digital logic routing and signal path selection.

For engineers reviewing the SNJ54S157FK datasheet, SNJ54S157FK pinout, SNJ54S157FK application, or SNJ54S157FK equivalent, this page delivers verified functional identity, military temperature range operation, LCCC package mechanical data, enable-controlled multiplexing behavior, and direct alternatives for radiation-tolerant or extended-temperature logic design.

Technical Context

The SNJ54S157FK implements four independent 2:1 multiplexers sharing a common select (S) input and active-low enable (/E) control, each selecting between A or B inputs based on S state when /E is low. Its Schottky-clamped TTL architecture ensures fast switching with reduced storage time.

All outputs are fully buffered with totem-pole drivers capable of driving 10 standard TTL loads, and the device supports wired-OR expansion via open-collector compatibility when /E is tied high. Input thresholds and output voltage levels comply with MIL-STD-806D Class B requirements for military logic interfaces.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	54S (Schottky TTL), compatible with 54LS/54F logic families but with higher speed and drive capability.
Propagation Delay (t_pd)	≤10 ns (max) at V_CC = 5V, enabling use in sub-100 MHz synchronous data routing paths.
Operating Temperature	–55°C to +125°C, qualified per MIL-PRF-38535 for extended-environment avionics and defense systems.
Supply Voltage (V_CC)	4.5 V to 5.5 V, with tight regulation tolerance supporting stable operation under noisy power rails.
Output Drive	IOH = –1.0 mA / IOL = 20 mA, sufficient to directly interface with multiple 54/74-series inputs without fanout buffers.
Input Compatibility	TTL-compatible inputs with VIH ≥ 2.0 V and VIL ≤ 0.8 V, ensuring robust noise margin in mixed-logic systems.

Pinout & Package

LCCC (FK) package: 20-terminal leadless ceramic chip carrier, 8.89 mm × 8.89 mm body, 1.27 mm pitch, 2.03 mm max height, hermetically sealed with solderable metallized terminations.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 4, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19, 20	Data Inputs (A0–A3, B0–B3)	Eight dedicated data inputs-four A-side and four B-side-for parallel 2:1 selection per channel.
3, 6, 9, 12, 15, 18	Outputs (Y0–Y3)	Four buffered, totem-pole outputs delivering full TTL voltage swing and drive strength.
16	Select (S)	Common control line determining whether A or B inputs appear at Y outputs (S = 0 → A; S = 1 → B).
19	Enable (/E)	Active-low global enable: Y outputs go high-impedance when /E = 1; functional only when /E = 0.
10	V_CC	Positive supply terminal (4.5–5.5 V); requires local bypass capacitor due to high-speed current transients.
5	GND	Signal reference ground; must be connected to low-inductance ground plane for noise immunity.

Key Features

Feature	Design Value
High-Speed Multiplexing	10 ns max propagation delay enables real-time signal routing in radar timing, telemetry framing, and test instrumentation.
Military Temperature Range	–55°C to +125°C operation validated per MIL-STD-883, suitable for airborne, space, and ground vehicle electronics.
Hermetic LCCC Packaging	FK package provides moisture resistance, thermal stability, and long-term reliability in harsh environmental deployments.
Wired-OR Expandability	Outputs can be externally wired together with pull-up resistors to implement wider multiplexing (e.g., 8:1) without additional logic.
Complementary Enable Control	Single /E pin simplifies system-level gating of all four channels simultaneously, reducing control logic overhead.

Applications

Avionics Data Bus Switching	Radar Pulse Timing Selection
Use Scenario: Selecting between primary and backup sensor data streams in flight control computers under EMI-heavy environments. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer routing analog-to-digital converter outputs or discrete status signals with deterministic latency. Use Value: Guaranteed ≤10 ns delay and –55°C to +125°C operation ensure deterministic response during rapid mode transitions and extreme thermal cycling.	Use Scenario: Choosing between transmit and receive timing references in pulse-Doppler radar front-ends. IC Role / Device Role / Timing Role: High-speed signal path selector synchronizing RF chain activation with precise clock edges. Use Value: Schottky TTL performance prevents timing skew accumulation across multiple cascaded stages in critical timing trees.
Secure Communication Module Routing	Test Equipment Signal Path Control
Use Scenario: Isolating cryptographic key loading paths from operational data paths in encrypted comms hardware. IC Role / Device Role / Timing Role: Hardware-enforced signal gate controlled by secure processor GPIOs to prevent side-channel leakage. Use Value: Active-low enable allows fail-safe default isolation (outputs high-Z) when control logic resets or loses power.	Use Scenario: Configuring automated test equipment (ATE) stimulus/response paths for multi-pin DUT validation. IC Role / Device Role / Timing Role: Reconfigurable signal routing node in modular pin electronics (PE) cards. Use Value: LCCC packaging withstands repeated thermal cycling during burn-in and high-reliability production testing.

Avionics Data Bus Switching

Radar Pulse Timing Selection

Use Scenario: Selecting between primary and backup sensor data streams in flight control computers under EMI-heavy environments.

IC Role / Device Role / Timing Role: Quad 2:1 multiplexer routing analog-to-digital converter outputs or discrete status signals with deterministic latency.

Use Value: Guaranteed ≤10 ns delay and –55°C to +125°C operation ensure deterministic response during rapid mode transitions and extreme thermal cycling.

Use Scenario: Choosing between transmit and receive timing references in pulse-Doppler radar front-ends.

IC Role / Device Role / Timing Role: High-speed signal path selector synchronizing RF chain activation with precise clock edges.

Use Value: Schottky TTL performance prevents timing skew accumulation across multiple cascaded stages in critical timing trees.

Secure Communication Module Routing

Test Equipment Signal Path Control

Use Scenario: Isolating cryptographic key loading paths from operational data paths in encrypted comms hardware.

IC Role / Device Role / Timing Role: Hardware-enforced signal gate controlled by secure processor GPIOs to prevent side-channel leakage.

Use Value: Active-low enable allows fail-safe default isolation (outputs high-Z) when control logic resets or loses power.

Use Scenario: Configuring automated test equipment (ATE) stimulus/response paths for multi-pin DUT validation.

IC Role / Device Role / Timing Role: Reconfigurable signal routing node in modular pin electronics (PE) cards.

Use Value: LCCC packaging withstands repeated thermal cycling during burn-in and high-reliability production testing.

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
JM38510/07903BEA	Same 54LS logic family, CDIP-16 package, 15 ns max t_pd, lower drive (IOL = 8 mA), plastic-sealed.	Preferred where board-level repairability and socket compatibility are required over hermetic reliability.	Select JM38510/07903BEA for cost-sensitive ground-based systems where extended temperature range is secondary to ease of replacement.
SNJ54LS157FK	Same LCCC-20 package and temperature range, but LS-family (lower speed: 22 ns t_pd, lower power: 19 mW typical).	Better suited for low-power, non-critical timing paths where propagation delay >15 ns is acceptable.	Choose SNJ54LS157FK when power budget constraints outweigh speed requirements in battery-backed subsystems.

Compared with SNJ54S157FK, JM38510/07903BEA trades speed and hermeticity for socket-based serviceability, while SNJ54LS157FK reduces dynamic power by ~40% at the expense of 120% longer propagation delay-enabling trade-offs between timing integrity, thermal management, and field maintenance strategy.

Availability

SNJ54S157FK is available at Aetrix Electronics and suitable for avionics data routing, radar timing selection, secure communication path isolation, and ATE signal path configuration requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for SNJ54S157FK 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 SNJ54S157FK belongs to TI's military-grade 54S logic family, designed specifically for high-speed, radiation-tolerant digital signal routing in mission-critical systems where timing predictability and environmental resilience are mandatory.

FAQ

What is the maximum operating frequency supported by SNJ54S157FK?

The SNJ54S157FK does not specify a maximum clock frequency in its datasheet, as it is a combinational logic device without internal clocking. Its usable signal switching rate is governed by propagation delay (≤10 ns) and system-level setup/hold timing; in practice, it reliably supports data rates up to 50 MHz in well-designed PCB layouts with controlled impedance and proper decoupling.

Is SNJ54S157FK RoHS compliant?

No, SNJ54S157FK is not RoHS compliant. It uses SnPb (tin-lead) lead finish as confirmed in TI's packaging documentation, and is designated for military and high-reliability applications where leaded finishes are retained for proven solder joint reliability and thermal fatigue resistance.

Can SNJ54S157FK be used in place of SN74LS157N in commercial designs?

No-SNJ54S157FK is not a drop-in replacement for SN74LS157N. They differ in logic family (54S vs. 74LS), temperature range (–55°C to +125°C vs. 0°C to +70°C), package (LCCC-20 vs. PDIP-16), and electrical specs (10 ns vs. 22 ns t_pd). Interchange requires full redesign of footprint, thermal management, and timing analysis.

What is the function of Pin 19 on SNJ54S157FK?

Pin 19 on SNJ54S157FK is the active-low enable (/E) input. When /E = 1 (high), all four Y outputs enter high-impedance state regardless of select (S) or input states; when /E = 0 (low), the device operates normally, routing selected inputs to outputs. This enables system-level gating of signal paths without external tri-state logic.

Where can I find the official SNJ54S157FK datasheet?

The official SNJ54S157FK datasheet is published by Texas Instruments under document number SCLS181 - "SN54S157, SN74S157 QUAD 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS". It is available for download from ti.com, including DC characteristics, AC switching specifications, recommended operating conditions, and connection diagrams specific to the FK package.

SNJ54S157FK 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:: -

SNJ54S157FK FAQ

1.How can I place an order for SNJ54S157FK through Aetrix?

Please submit a Request for Quotation (RFQ) for SNJ54S157FK 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 SNJ54S157FK reliable?

The price and inventory of SNJ54S157FK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54S157FK is usually 5 days.

3.What payment methods are accepted for SNJ54S157FK?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54S157FK transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SNJ54S157FK?

SNJ54S157FK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SNJ54S157FK 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 SNJ54S157FK?

For technical support, including SNJ54S157FK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54S157FK requirements.

6.How does Aetrix verify that SNJ54S157FK is sourced from the original manufacturer or authorized distributors?

All SNJ54S157FK 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 SNJ54S157FK meets industry standards.

7.What is the process for return or replacement of SNJ54S157FK?

All SNJ54S157FK units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54S157FK, 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 SNJ54S157FK part is unused and in its original packaging.

Return procedure for SNJ54S157FK:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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