Texas Instruments SNJ54F245FK

Overview

SNJ54F245FK from Texas Instruments is a military-grade octal bus transceiver with 3-state outputs, designed for bidirectional asynchronous data transfer between two 8-bit buses (A↔B) in harsh-environment systems. It features direction control (DIR), output enable (OE), ±55°C to +125°C operating range, 20-pin LCCC (FK) package, and supports up to 6 ns propagation delay at 5 V.

For engineers reviewing the SNJ54F245FK datasheet, SNJ54F245FK pinout, SNJ54F245FK application, or SNJ54F245FK equivalent, this page delivers verified electrical specs, military-qualified thermal performance, functional truth table behavior, and precise LCCC mechanical interface details required for avionics, defense computing, and space-qualified backplane designs.

Technical Context

The SNJ54F245FK implements TTL-compatible bipolar F logic with dual 8-bit bidirectional data paths controlled by DIR and OE inputs. Its 3-state outputs provide high-impedance isolation when OE is high, enabling bus sharing without contention. The device uses standard positive-logic control signals and drives loads directly without external pull-ups.

It operates exclusively from a single 4.5–5.5 V supply and is characterized across the full military temperature range (–55°C to +125°C). Input thresholds are VIH ≥ 2.0 V and VIL ≤ 0.8 V; output drive capability is 24 mA (A-side low) and 64 mA (B-side low) at VCC = 4.5 V, ensuring robust noise immunity and bus loading margin in mission-critical interconnects.

Key Specifications

Pinout & Package

SNJ54F245FK is housed in a 20-terminal Leadless Ceramic Chip Carrier (LCCC, FK package), 8.89 mm × 8.89 mm, 1.27 mm pitch, with ceramic body and solderable metallized terminations. Designed for hermetic sealing and high-reliability mounting in multilayer ceramic substrates.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SNJ54F245FK, JM38510/34803B2A adds space-level reliability assurance without altering pinout or timing, while SNJ54F245J trades LCCC hermeticity and thermal performance for socket-based serviceability - making SNJ54F245FK optimal for new high-density, high-reliability embedded designs.

Availability

SNJ54F245FK is available at Aetrix Electronics and suitable for avionics data bus interfaces, ground vehicle mission computers, tactical radio baseband links, and space-qualified payload controllers requiring stable component supply under extended temperature and long-lifecycle programs.

Supply support for SNJ54F245FK 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 aerospace, defense, and industrial markets.

The SNJ54F series belongs to TI's military-qualified TTL logic family, engineered specifically for deterministic timing, wide-temperature operation, and compatibility with legacy 5 V digital systems in safety-critical platforms.

FAQ

What is the maximum propagation delay of the SNJ54F245FK at worst-case conditions?

The SNJ54F245FK has a maximum propagation delay (tPLH/tPHL) of 7 ns under worst-case conditions: VCC = 4.5 V, CL = 50 pF, RL = 500 Ω, and TA = –55°C to +125°C. This value is confirmed in the "Switching Characteristics" table of the official SDFS010A datasheet and applies to all A↔B and B↔A data paths. The SNJ54F245FK maintains consistent timing across its full military temperature range, making it suitable for time-critical bus arbitration.

Does the SNJ54F245FK support hot-swapping or live insertion into an active bus?

The SNJ54F245FK does not include built-in hot-swap protection circuitry. However, its 3-state outputs and high-impedance isolation (when OE = HIGH) allow safe insertion if the OE pin is held inactive until power and ground stabilize. Per datasheet absolute maximum ratings, any output may tolerate –0.5 V to 5.5 V in the disabled state - enabling controlled live insertion when coordinated with system-level power sequencing. Always verify bus voltage levels before asserting OE on SNJ54F245FK.

What is the pin 1 marking and orientation for the SNJ54F245FK LCCC package?

The SNJ54F245FK uses a standard LCCC (FK) package with pin 1 located at the corner adjacent to the index notch or laser-marked dot on the ceramic body. Per TI's generic LCCC outline (4229370/A), pin 1 is identified by a small chamfer or mark on the top surface near the corner; the pin numbering proceeds counterclockwise. The part marking "85511012A" appears on the top surface, and the device orientation follows JEDEC MO-115 standards for leadless carriers.

Can the SNJ54F245FK be used with 3.3 V logic systems?

No - the SNJ54F245FK is strictly a 5 V TTL device with VIH minimum of 2.0 V and VIL maximum of 0.8 V, but it requires VCC = 4.5–5.5 V for correct internal biasing and output swing. Driving its inputs from 3.3 V logic may result in marginal or non-functional high-level recognition, and its outputs swing to ~3.4 V (VOH min at IOH = –3 mA), which falls below typical 3.3 V VIH thresholds. Use level translators or compatible 3.3 V transceivers (e.g., SN74LVC245A) instead of SNJ54F245FK in mixed-voltage systems.

Is the SNJ54F245FK RoHS compliant?

No - the SNJ54F245FK uses SnPb (tin-lead) lead finish and is explicitly marked "No" for RoHS compliance in TI's packaging addendum. It is intended for military, aerospace, and legacy systems where Pb-free exemptions apply under JESD67 or MIL-STD-1276. For RoHS-compliant alternatives, consider modern replacements like SN74LVC245A (commercial) or radiation-hardened equivalents qualified under MIL-PRF-38535 Class K with Pb-free finishes.