Texas Instruments SNJ54AS825AJT

Overview

SNJ54AS825AJT from Texas Instruments is a military-grade 8-bit D-type edge-triggered flip-flop with three-state outputs, designed for high-capacitance bus driving in multiuser register and I/O port applications. It operates across −55°C to 125°C, features CLKEN-controlled clock gating, asynchronous CLR, and triple buffered OE1/OE2/OE3 enables. Key specs include tPLH/tPHL ≤ 9/13.5 ns (VCC = 4.5–5.5 V), IOL = 32 mA, IOH = −24 mA, and 24-pin ceramic DIP (JT) package.

For engineers reviewing the SNJ54AS825AJT datasheet, SNJ54AS825AJT pinout, SNJ54AS825AJT application, or SNJ54AS825AJT equivalent, this page delivers verified timing behavior, military-temperature operation limits, 3-state output enable sequencing, undershoot-protection circuitry, and functional equivalence to AM29825 - all critical for legacy aerospace, defense, and industrial control system design and obsolescence mitigation.

Technical Context

This device implements eight independent D-type flip-flops with noninverting data paths, each synchronized on the low-to-high CLK transition when CLKEN is low. The asynchronous active-low CLR forces all Q outputs low regardless of clock state, while OE1/OE2/OE3 collectively control 3-state output drivers - any one high places all eight outputs in high-impedance mode without affecting internal latch states.

Its architecture supports bidirectional bus interfacing without pull-up components due to strong drive capability (32 mA sink / −24 mA source) and undershoot-protection circuitry on outputs. Power-up default is high-impedance output state, and buffered control inputs minimize DC loading on upstream logic - essential for stable operation in noise-prone military platforms.

Key Specifications

Pinout & Package

SNJ54AS825AJT is housed in a 24-lead ceramic dual-in-line package (CDIP, JT), hermetically sealable per MIL-STD-1835 GDIP3-T24, with 0.300-inch width and 0.100-inch lead pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit bus interface flip-flop applications.

Compared with SNJ54AS825AJT, SNJ54AS825AFK offers identical functionality in a surface-mount LCCC package requiring layout change, while 5962-9078003M3A provides the same JT footprint with full QML-38535 Class V certification - making SNJ54AS825AJT the optimal choice for legacy JT-replacement scenarios where cost, availability, and drop-in compatibility are prioritized.

Availability

SNJ54AS825AJT is available at Aetrix Electronics and suitable for avionics data bus interface, military radar signal register, tactical radio baseband buffer, and secure crypto module I/O port applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SNJ54AS825AJT 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 leader specializing in analog, embedded processing, and logic solutions for industrial, automotive, aerospace, and defense markets.

The SNJ54AS825AJT belongs to TI's military-grade AS-family logic portfolio, engineered for high-speed, high-reliability bus interfacing in mission-critical systems operating under extreme environmental stress.

FAQ

What is the operating temperature range of the SNJ54AS825AJT?

The SNJ54AS825AJT is characterized for operation from −55°C to 125°C, meeting full military temperature specifications per MIL-STD-883. This range is validated across all electrical parameters including propagation delay, output drive, and input thresholds - ensuring reliable performance in aircraft, ground vehicles, and space-qualified electronics where thermal extremes are routine.

Does the SNJ54AS825AJT support true bidirectional data flow?

The SNJ54AS825AJT does not implement internal bidirectional switching logic, but enables bidirectional bus use via external control of its three-state outputs and D inputs. When OE1–OE3 are low, Q outputs drive the bus; when any OE is high, outputs go high-Z, allowing external devices to drive the same lines - a standard method for half-duplex parallel bus architectures in systems using SNJ54AS825AJT.

How does the CLKEN pin function in the SNJ54AS825AJT?

In the SNJ54AS825AJT, CLKEN is an active-high clock enable that gates the internal clock buffer. When CLKEN is low, the device samples D inputs on each low-to-high CLK transition; when CLKEN is high, the clock path is disabled and Q outputs retain their last latched values - providing synchronous data hold without requiring external latch strobes or additional control logic.

Is the SNJ54AS825AJT pin-compatible with the commercial SN74AS825A series?

No - the SNJ54AS825AJT uses a 24-pin ceramic DIP (JT) package, while SN74AS825A variants are offered in DW (SOIC), NT (plastic DIP), and FK (LCCC) packages with differing pin counts and layouts. Although functionally identical, SNJ54AS825AJT is not pin-compatible with any SN74AS825A variant due to package-specific pin mapping and military vs. commercial temperature grading.

What is the purpose of the NC pins on the SNJ54AS825AJT?

The SNJ54AS825AJT has eight no-connect (NC) pins - specifically pins 4, 5, 6, 16, 17, 18, 20, and 21 - which have no internal silicon connection. These pins must remain unconnected in the PCB layout per TI's datasheet guidance; soldering or routing to them may cause mechanical stress or unintended coupling, compromising reliability in high-vibration military deployments where SNJ54AS825AJT is commonly used.