Texas Instruments SNJ54ALS1245AFK

Overview

SNJ54ALS1245AFK from Texas Instruments is a military-grade octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in high-reliability systems. It operates across –55°C to 125°C, features DIR-controlled directionality, OE-enabled 3-state isolation, and delivers tPLH/tPHL ≤19 ns at VCC = 4.5–5.5 V with CL = 50 pF - used in avionics backplane interfaces and ruggedized test equipment.

For engineers reviewing the SNJ54ALS1245AFK datasheet, SNJ54ALS1245AFK pinout, SNJ54ALS1245AFK application, or SNJ54ALS1245AFK equivalent, key selection criteria include its LCCC (FK) 20-pin ceramic package, –55°C to 125°C operating range, bidirectional DIR logic control, 3-state output enable timing (tPZH ≤30 ns), and compatibility with legacy 5-V TTL/ALS bus architectures.

Technical Context

This device implements dual 8-bit bidirectional data paths controlled by a single DIR input: low DIR enables B→A transmission, high DIR enables A→B transmission. The OE input independently places all outputs in high-impedance state regardless of DIR, enabling true bus isolation.

It belongs to the ALS logic family with guaranteed VIH ≥2 V, VIL ≤0.8 V, IOH = –12 mA / IOL = 8 mA drive capability, and ICC ≤40 mA under full-output switching at VCC = 5.5 V - optimized for low-power, noise-immune 5-V digital interconnects in mixed-signal environments.

Key Specifications

Pinout & Package

LCCC (FK) 20-pin leadless ceramic chip carrier: 8.89 mm × 8.89 mm body, 1.27 mm pitch, 2.03 mm max height, hermetically sealed, suitable for high-vibration and extended-temperature environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal bidirectional bus transceiver applications.

Compared with SNJ54ALS1245AFK, SNJ54ALS1645AFK offers identical performance and fit but differs only in part numbering convention, while 5962-88737012A provides the same hardware with full QML-38535 documentation support - making it the preferred choice for defense prime integrators requiring certified pedigree.

Availability

SNJ54ALS1245AFK is available at Aetrix Electronics and suitable for avionics data bus interfaces, secure test equipment backplanes, and ruggedized industrial PLC I/O expansion requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SNJ54ALS1245AFK 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 aerospace, defense, and industrial markets.

The SNJ54ALS1245AFK belongs to TI's military-qualified ALS logic family, engineered for deterministic 5-V bus interfacing in safety-critical systems where temperature resilience, radiation tolerance, and long-term parametric stability are mandatory.

FAQ

What is the operating temperature range specified for the SNJ54ALS1245AFK?

The SNJ54ALS1245AFK is characterized for operation from –55°C to 125°C, meeting full military temperature range requirements per MIL-STD-883. This specification is validated through temperature cycling, burn-in, and parametric testing across the entire range - not extrapolated or derated. The SNJ54ALS1245AFK maintains guaranteed tPLH ≤19 ns and VOL ≤0.4 V throughout this interval.

Is the SNJ54ALS1245AFK pin-compatible with the SN74ALS1245AN?

No, the SNJ54ALS1245AFK is not pin-compatible with the SN74ALS1245AN. While both share identical logic functionality and 20-pin count, the SNJ54ALS1245AFK uses an LCCC (FK) ceramic package with perimeter terminations, whereas the SN74ALS1245AN uses a plastic DIP (N) package with through-hole leads. Their pinouts differ in physical layout and terminal mapping - direct PCB replacement is not possible without redesign.

Does the SNJ54ALS1245AFK support hot-swap bus insertion?

The SNJ54ALS1245AFK supports controlled hot-swap operation when OE is held HIGH during insertion, placing all outputs in high-impedance state. Its absolute maximum rating allows VI(OE) up to 7 V and I/O port voltage up to 5.5 V, enabling safe pre-charge sequencing. However, TI does not specify bus-keeper or live-insertion protection circuitry - external current-limiting resistors and staggered power sequencing are required for robust hot-swap implementation with SNJ54ALS1245AFK.

What is the meaning of "SNJ" prefix in SNJ54ALS1245AFK?

The "SNJ" prefix in SNJ54ALS1245AFK denotes a Texas Instruments military-grade product manufactured to JANTXV or JANTX level per MIL-PRF-38535, with full QML qualification, extended temperature screening, and traceable lot documentation. It distinguishes the part from commercial SN74ALS1245AN variants and confirms compliance with defense procurement standards - the SNJ54ALS1245AFK is not a prototype or engineering sample.

Can the SNJ54ALS1245AFK be used with 3.3-V logic systems?

The SNJ54ALS1245AFK is not designed for direct 3.3-V logic interfacing. Its input thresholds (VIH ≥2 V, VIL ≤0.8 V) and output levels (VOH ≥2.4 V at IOL = 8 mA) assume a 5-V supply and TTL/ALS-compatible receivers. Driving or receiving 3.3-V signals requires level-shifting circuitry - TI recommends pairing the SNJ54ALS1245AFK with dedicated 5-V-to-3.3-V translators like the TXB0108 when interfacing with modern low-voltage FPGAs or microcontrollers.