Texas Instruments SN54HC125J

Overview

SN54HC125J from Texas Instruments is a quadruple bus buffer gate with independent 3-state outputs, designed for military-grade operation across –55°C to +125°C. It operates from 2 V to 6 V V_CC, delivers ±6 mA output drive at 5 V, and achieves 25 ns typical propagation delay (t_pd) at 6 V with 50 pF load - enabling robust signal buffering in high-reliability avionics and defense data buses.

For engineers reviewing the SN54HC125J datasheet, SN54HC125J pinout, SN54HC125J application, or SN54HC125J equivalent, key selection criteria include its CDIP-14 hermetic package, guaranteed operation over full military temperature range, 3-state output timing (t_en/t_dis ≤ 31 ns), low input current (±1 µA max), and compatibility with LSTTL loads.

Technical Context

The SN54HC125J implements four identical CMOS buffer stages, each with an active-low output-enable (OE) control and high-impedance (Z) state when OE = HIGH. Its logic function follows standard positive-logic truth table: Y = A when OE = LOW; Y = Z when OE = HIGH.

Designed for MIL-PRF-38535 compliance, it features enhanced ESD robustness (2000 V HBM), absolute maximum ratings up to 7 V V_CC, and junction temperature tolerance to 150°C. All parameters are production-tested per military screening requirements.

Key Specifications

Pinout & Package

SN54HC125J uses a 14-pin Ceramic Dual In-line Package (CDIP) with 0.300-inch wide body and 0.100-inch lead pitch. Pin numbering follows standard DIP convention (pin 1 top-left, pin 14 bottom-right). All NC pins are internally unconnected and must remain floating or grounded per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN54HC125J, SN74HC125N lacks military qualification and thermal margin, while SNJ54HC125J provides identical performance with enhanced documentation for defense procurement - making SN54HC125J the optimal balance of proven reliability and program flexibility.

Availability

SN54HC125J is available at Aetrix Electronics and suitable for avionics data bus interface, secure ground station control, and tactical vehicle ECU applications requiring stable component supply under extended temperature and high-reliability constraints.

Supply support for SN54HC125J 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 high-reliability logic solutions for aerospace, defense, and industrial markets.

The SN54HC125J belongs to TI's military-grade HC logic family, engineered specifically for mission-critical systems demanding guaranteed operation across extreme temperatures, radiation environments, and long service lifetimes.

FAQ

What is the operating temperature range of the SN54HC125J?

The SN54HC125J is specified for continuous operation from –55°C to +125°C ambient temperature, meeting MIL-PRF-38535 Class B requirements. This range is validated through temperature cycling, steady-state burn-in, and parametric testing at both extremes - confirming reliable functionality in jet engine bays, satellite payload compartments, and desert-deployed ground systems where the SN54HC125J serves as a critical bus interface element.

Does the SN54HC125J require external pull-up resistors on OE inputs?

No, the SN54HC125J does not require external pull-up resistors on OE inputs for normal operation. However, TI recommends tying unused OE inputs to V_CC via a pull-up resistor (minimum value determined by driver sink capability) to ensure high-impedance state during power-up or power-down transients. This prevents undefined output states that could cause bus contention - a critical safeguard when deploying the SN54HC125J in fault-tolerant avionics architectures.

How does the SN54HC125J differ from the SN74HC125 in terms of electrical performance?

The SN54HC125J exhibits higher propagation delay (25 ns max vs. 26 ns for SN74HC125 at 6 V), wider operating voltage tolerance (7 V absolute max vs. 7 V), and stricter input/output voltage limits under military conditions. Its I_CC is 160 µA max (vs. 80 µA for SN74HC125), reflecting enhanced test coverage and screening - all verified per MIL-PRF-38535 rather than commercial AEC or JEDEC standards. These differences make the SN54HC125J suitable where the SN74HC125 would fail qualification.

Can the SN54HC125J drive LSTTL loads directly?

Yes, the SN54HC125J can drive up to 15 LSTTL loads directly, as confirmed by its ±6 mA output drive specification at 5 V V_CC. This capability eliminates the need for intermediate buffer stages in legacy military systems using LSTTL logic families. The SN54HC125J maintains valid VOH/VOL levels across its full temperature range, ensuring interoperability with LSTTL inputs even under worst-case voltage and thermal conditions - a key requirement in the systems where SN54HC125J is deployed.

Is the SN54HC125J RoHS compliant?

The SN54HC125J is not RoHS compliant in its standard configuration, as it uses leaded solder and non-RoHS finishes per MIL-PRF-38535 Class B requirements. TI offers RoHS-compliant alternatives such as SN74HC125D (SOIC) for commercial applications, but the SN54HC125J retains leaded terminations to ensure solder joint reliability under thermal cycling and mechanical shock - a mandatory feature for flight hardware where the SN54HC125J is commonly applied.