Texas Instruments SNJ54LS258BFK

Overview

SNJ54LS258BFK from Texas Instruments is a military-grade quadruple 2-line-to-1-line data selector/multiplexer in a 20-pin LCCC (FK) package, operating across –55°C to +125°C. It features TTL-compatible inputs and outputs, 16 mA output drive capability, and dual enable control (G̅₁ and G̅₂) for independent channel gating. It is used in aerospace data routing, avionics bus arbitration, and radiation-tolerant logic subsystems.

For engineers reviewing the SNJ54LS258BFK datasheet, SNJ54LS258BFK pinout, SNJ54LS258BFK application, or SNJ54LS258BFK equivalent, this page delivers verified functional identity, military temperature range validation, LCCC package mapping, dual-enable logic behavior, and direct alternatives with documented parameter divergence.

Technical Context

The SNJ54LS258BFK implements four independent 2:1 multiplexers sharing common select (S) and dual active-low enable (G̅₁, G̅₂) inputs. Each channel routes either I₀ or I₁ to Y based on S, but only when both enables are low - enabling hierarchical gating in multi-stage logic trees.

It belongs to the SN54LS family, fabricated using bipolar Schottky TTL technology, delivering propagation delays of 15 ns (max) at V_CC = 5 V and guaranteed fan-out of 10 LS-TTL loads. Its LCCC package provides hermetic sealing and thermal stability required for high-reliability military platforms.

Key Specifications

Pinout & Package

SNJ54LS258BFK uses a 20-pin LCCC (FK) package with leads arranged in a square perimeter and no external leads - terminals are soldered directly to metallized pads on ceramic substrate. Pin 1 is marked by a laser dot or notch orientation indicator.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2:1 multiplexer applications.

Compared with SNJ54LS258BFK, SNJ54LS257BFK simplifies enable control at the cost of routing flexibility, while JM38510/30906B2A offers identical performance with alternative military certification lineage - both preserve LCCC reliability but differ in system-level gating strategy or procurement chain requirements.

Availability

SNJ54LS258BFK is available at Aetrix Electronics and suitable for avionics integration, satellite subsystem design, and missile guidance electronics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SNJ54LS258BFK 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 manufacturer specializing in analog, embedded processing, and high-reliability logic solutions for defense, space, and industrial markets.

The SN54LS series was designed for military and aerospace applications demanding guaranteed operation across extreme temperatures, radiation tolerance, and long-term reliability - with SNJ54LS258BFK serving as a hardened quad multiplexer for deterministic signal routing.

FAQ

What is the function of SNJ54LS258BFK?

SNJ54LS258BFK is a quadruple 2-line-to-1-line data selector/multiplexer with dual active-low enable inputs (G̅₁ and G̅₂) and a common select line (S). It routes one of two inputs (I₀ or I₁) to each of four outputs (YA–YD) when both enables are asserted low. Its logic behavior and timing are fully specified in TI's SDLS148 datasheet.

Is SNJ54LS258BFK pin-compatible with SN74LS258B?

No - SNJ54LS258BFK uses a 20-pin LCCC (FK) package, while SN74LS258B is offered in 16-pin PDIP (N), SOIC (D), or CDIP (J) packages. The pin count, physical layout, and thermal/mechanical interface differ fundamentally. Direct PCB replacement is not possible without redesign.

What is the operating temperature range of SNJ54LS258BFK?

SNJ54LS258BFK is rated for –55°C to +125°C, qualified per MIL-PRF-38535 Class V for high-reliability military and aerospace use. This range is validated through temperature cycling, burn-in, and parametric testing - exceeding the 0°C to +70°C range of commercial SN74LS258B variants.

Does SNJ54LS258BFK require external pull-up resistors on its outputs?

No - SNJ54LS258BFK features totem-pole TTL outputs capable of sourcing and sinking up to 16 mA. Pull-up resistors are unnecessary unless interfacing with non-TTL loads (e.g., open-collector systems), in which case design-specific termination applies - not a requirement of SNJ54LS258BFK itself.

How does the dual-enable feature (G̅₁ and G̅₂) work in SNJ54LS258BFK?

In SNJ54LS258BFK, both G̅₁ and G̅₂ must be logic low to enable any output (YA–YD). If either is high, all outputs go high-impedance (not logic high). This allows hierarchical control - e.g., G̅₁ may gate two channels while G̅₂ gates the other two, or both used together for global disable - a key distinction from SNJ54LS257BFK's single-G̅ architecture.