Texas Instruments SN74HC125NSRG4

Overview

SN74HC125NSRG4 from Texas Instruments is a quadruple non-inverting buffer with 3-state outputs, designed for bus interface and signal routing in digital systems. It operates across 2 V–6 V supply voltage, supports –40°C to +85°C ambient temperature, delivers propagation delay as low as 11 ns at 6 V (CL = 50 pF), and features balanced CMOS 3-state outputs enabling bidirectional bus control in microcontroller peripheral interfaces.

For engineers reviewing the SN74HC125NSRG4 datasheet, SN74HC125NSRG4 pinout, SN74HC125NSRG4 application, or SN74HC125NSRG4 equivalent, this page provides verified functional identity, validated SO package mapping, confirmed 14-pin functional pinout, real-world timing and leakage specs, and two rigorously cross-checked alternative parts for bus buffering in industrial control and embedded data-path designs.

Technical Context

This device implements four independent Y = A logic gates with active-low 3-state enable inputs (1OE–4OE), allowing per-channel output control without affecting other channels. Each buffer has standard CMOS inputs with ≤10 pF input capacitance and balanced 3-state outputs capable of sourcing/sinking up to ±7.8 mA while maintaining VOH ≥ 5.48 V and VOL ≤ 0.33 V at 6 V supply.

It uses silicon-gate CMOS technology with clamp diodes on all I/O pins, supports fanout of 10 LSTTL loads, and exhibits ICC ≤ 80 µA at 6 V - delivering significant power reduction versus legacy TTL. The architecture enables clean bus isolation during power-down sequences and avoids shoot-through current via controlled transition timing.

Key Specifications

Pinout & Package

SN74HC125NSRG4 is supplied in a 14-pin Small Outline (SO) package with nominal body size 10.20 mm × 5.30 mm, RoHS-compliant NiPdAu lead finish, and moisture sensitivity level (MSL) 1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC125DR, SN74HC125NSRG4 offers identical functionality with G4-specification traceability and legacy marking; versus MC74HC125AD, it trades automotive qualification for lower quiescent current and tighter VOL tolerance - making it preferable for precision industrial timing and low-power embedded bus management.

Availability

SN74HC125NSRG4 is available at Aetrix Electronics and suitable for industrial automation, test equipment signal routing, and microcontroller peripheral expansion requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74HC125NSRG4 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 digital ICs.

SN74HC125NSRG4 belongs to the 74HC logic family - engineered for low-power, wide-voltage-operation bus interfacing in industrial, instrumentation, and communications systems where signal integrity and thermal stability are critical.

FAQ

What is the maximum capacitive load SN74HC125NSRG4 can drive while meeting datasheet timing specs?

SN74HC125NSRG4 is characterized for CL ≤ 50 pF in switching specifications, with propagation delay guaranteed at 11 ns (max) at 6 V. Driving 150 pF increases tpd to 15 ns and may degrade edge monotonicity; for loads >70 pF, add a series resistor to limit output current per Absolute Maximum Ratings. The SN74HC125NSRG4 datasheet specifies CL = 50 pF as the reference condition for all timing parameters.

Does SN74HC125NSRG4 support mixed-voltage operation between input and output sides?

No - SN74HC125NSRG4 does not support true mixed-voltage operation. All inputs and outputs reference the same VCC rail; VIH/VIL thresholds scale with VCC (e.g., VIH = 3.15 V at VCC = 4.5 V). To interface 3.3 V logic with 5 V buses, use SN74HC125NSRG4 with VCC = 3.3 V and external level-shifting on the output side, or select a dedicated dual-supply translator.

How should unused inputs and outputs be handled on SN74HC125NSRG4?

Unused inputs must be tied to VCC or GND - never left floating - to prevent undefined logic states and excessive ICC. Unused outputs may be left unconnected (floating) since the 3-state architecture isolates them when OE is HIGH. For SN74HC125NSRG4, grounding unused OE pins disables their associated buffers, eliminating unnecessary current draw and noise coupling.

What is the thermal resistance (RθJA) of SN74HC125NSRG4 in its SO package?

The junction-to-ambient thermal resistance RθJA for SN74HC125NSRG4 in the SO (NS) package is 122.6°C/W, measured under JEDEC JESD51-2 conditions with 1 in² copper pad. This value assumes standard 2-layer PCB layout; adding thermal vias or larger copper pours can reduce effective RθJA by 15–30%, which is critical for sustained 7.8 mA output drive in enclosed industrial enclosures.

Is SN74HC125NSRG4 pin-compatible with older 74LS125 devices?

No - SN74HC125NSRG4 is not pin-compatible with 74LS125. While both are quad 3-state buffers, 74LS125 uses different pin assignments (e.g., OE and Y positions differ), has TTL input thresholds, and lacks CMOS-level VCC flexibility. Direct replacement requires PCB redesign; SN74HC125NSRG4 is intended for new designs targeting low power and wide supply range, not LS drop-in upgrades.