Texas Instruments SNJ54HC112FK

Overview

SNJ54HC112FK from Texas Instruments is a dual J-K negative-edge-triggered flip-flop with independent preset (PRE) and clear (CLR) inputs, operating across 2V–6V supply range, delivering 13ns typical propagation delay at 6V, ±4mA output drive at 5V, and 40μA max ICC - used in military-grade timing control, synchronous state machines, and clock-domain synchronization in telecom infrastructure.

For engineers reviewing the SNJ54HC112FK datasheet, SNJ54HC112FK pinout, SNJ54HC112FK application, or SNJ54HC112FK equivalent, this page delivers verified functional behavior, LCCC-20 package interface details, timing constraints for negative-edge clocking, and validated alternatives for high-reliability logic design.

Technical Context

The SNJ54HC112FK implements two fully independent J-K flip-flops, each triggered on the falling edge of CLK while PRE and CLR override all other inputs asynchronously. Its CMOS architecture ensures rail-to-rail output swing, low input current (≤1μA), and compatibility with TTL loads (up to 10 LSTTL).

Operation requires strict adherence to setup time (17ns min at 6V) and hold time (0ns) relative to CLK↓; J/K inputs may change freely after hold time without affecting Q/Q outputs. Toggling is achieved by tying J=K=HIGH, enabling divide-by-two and counter applications.

Key Specifications

Pinout & Package

LCCC (FK) package: 20-terminal leadless ceramic chip carrier, 8.89mm × 8.89mm body size, 1.27mm pitch, 2.03mm max height, hermetically sealed for high-reliability mil-aero use.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual J-K flip-flop applications.

Compared with SNJ54HC112FK, SNJ54LS112J offers greater drive strength but consumes >600× more static power, while SN74HC112N provides identical logic functionality at lower cost and RoHS compliance but sacrifices military-grade reliability and temperature range.

Availability

SNJ54HC112FK is available at Aetrix Electronics and suitable for telecom infrastructure, motor drivers, and server power management requiring stable component supply across extended temperature and long lifecycle commitments.

Supply support for SNJ54HC112FK 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 specializing in analog, embedded processing, and logic solutions, with over 50 years of innovation in high-reliability IC design.

The SNJ54HC112FK belongs to TI's military-grade HC logic family, engineered for deterministic timing, radiation-tolerant operation, and extended environmental resilience in defense, aerospace, and critical infrastructure systems.

FAQ

What is the maximum clock frequency supported by SNJ54HC112FK?

The SNJ54HC112FK supports up to 29MHz maximum clock frequency at VCC = 6V and TA = 25°C, as specified in the Switching Characteristics table (Section 5.6). At 2V supply, fmax drops to 5MHz. Designers must verify timing margins using worst-case tpd (42ns max at 6V) and setup/hold requirements across full temperature range.

Does SNJ54HC112FK require external pull-up or pull-down resistors on unused inputs?

Yes - all unused inputs of SNJ54HC112FK must be tied to VCC or GND per TI application report SCBA004. Floating J, K, PRE, or CLR inputs can cause undefined output states, increased ICC, or oscillation. For toggle mode, tie J=K=VCC; for reset-dominant use, tie PRE and CLR to GND through appropriate series resistance if driven actively.

Is SNJ54HC112FK pin-compatible with SN74HC112N?

No - SNJ54HC112FK uses a 20-pin LCCC (FK) package with different pin count, layout, and terminal configuration than the 16-pin PDIP (N) package of SN74HC112N. They share identical logic function and AC/DC specifications but require distinct PCB footprints and thermal management approaches.

What is the meaning of "negative-edge-triggered" in SNJ54HC112FK operation?

"Negative-edge-triggered" means SNJ54HC112FK samples J and K input states and updates Q/Q outputs only on the falling (high-to-low) transition of the CLK signal. This behavior is defined in the Function Table (Section 7.3) and ensures synchronization against clock skew in cascaded register chains, unlike level-sensitive or positive-edge devices.

Can SNJ54HC112FK operate reliably at 2.5V supply voltage?

Yes - SNJ54HC112FK is fully characterized from 2V to 6V, including 2.5V. At 2.5V, tpd increases to 165ns max (Section 5.6), fmax reduces to 3.4MHz, and VOH/VOL meet 2.3V/0.2V minimums (Section 5.4). System-level timing analysis must account for these derated parameters in 2.5V designs.