Texas Instruments SN74AHC125QDRG4Q1

Overview

SN74AHC125QDRG4Q1 from Texas Instruments is an automotive-qualified quadruple bus buffer gate with independent 3-state outputs, operating from 2 V to 5.5 V, delivering ±8 mA output drive at 5 V, 14-pin SOIC package, and rated for −40°C to +125°C. It serves as a level-shifting, bidirectional bus isolation device in CAN/LIN interface subsystems and motor control logic.

For engineers reviewing the SN74AHC125QDRG4Q1 datasheet, SN74AHC125QDRG4Q1 pinout, SN74AHC125QDRG4Q1 application, or SN74AHC125QDRG4Q1 equivalent, key selection criteria include its AEC-Q100 Grade 1 qualification, 3.8 ns typical propagation delay at 5 V/15 pF, 3-state enable timing asymmetry (tPHZ/tPLZ), thermal resistance of 86°C/W in SOIC, and compatibility with 1.8-V/3.3-V/5-V mixed-voltage buses.

Technical Context

The SN74AHC125QDRG4Q1 implements four independent CMOS buffer channels, each with active-low output-enable (OE) control enabling high-impedance state during power sequencing. Its EPIC™ process ensures latch-up immunity >250 mA per JESD17 and robust ESD tolerance (±2000 V HBM).

Each channel operates as a non-inverting buffer: when OE is low, A → Y passes data; when OE is high, Y enters high-Z. The device supports hot-swap and bus-sharing applications via controlled output disable timing-tPZH/tPZL (enable-to-output disable) and tPHZ/tPLZ (enable-to-output enable)-with specified values across 3.3 V and 5 V supply conditions.

Key Specifications

Pinout & Package

SN74AHC125QDRG4Q1 uses a 14-pin SOIC (D) package measuring 8.65 mm × 6 mm with 1.27 mm lead pitch and 1.75 mm max height. Thermal pad is not present (SOIC variant).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC125AQPWRQ1 and MC74VHC125DTG, the SN74AHC125QDRG4Q1 uniquely balances wide supply flexibility (2–5.5 V), AEC-Q100 Grade 1 compliance, and predictable 3-state timing-making it optimal for mixed-voltage automotive subsystems requiring long-term reliability under thermal stress.

Availability

SN74AHC125QDRG4Q1 is available at Aetrix Electronics and suitable for flow meter interfaces, programmable logic controllers, and Power over Ethernet (PoE) management circuits requiring stable component supply across automotive production lifecycles.

Supply support for SN74AHC125QDRG4Q1 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 automotive-grade silicon solutions with over 50 years of innovation in high-reliability electronics.

The SN74AHC125QDRG4Q1 belongs to TI's automotive logic portfolio, designed specifically for robust signal buffering in harsh-environment vehicle networks-including body control modules, chassis electronics, and infotainment backplanes.

FAQ

What is the maximum operating temperature for SN74AHC125QDRG4Q1?

The SN74AHC125QDRG4Q1 is rated for continuous operation from −40°C to +125°C ambient temperature, meeting AEC-Q100 Grade 1 requirements. This specification is validated across the full VCC range (2 V to 5.5 V) and applies to the SOIC (D) package variant SN74AHC125QDRG4Q1. Thermal derating is not required within this range when mounted per JEDEC MS-012 standards with adequate PCB copper area.

Does SN74AHC125QDRG4Q1 support 1.8-V input logic levels?

Yes, SN74AHC125QDRG4Q1 accepts 1.8-V logic inputs when operated at VCC ≥ 2 V. Its VIH threshold is 1.5 V at VCC = 2 V, providing 0.3 V noise margin for 1.8-V CMOS drivers. However, output swing will be limited to 0–VCC, so level translation to higher rails (e.g., 3.3 V or 5 V) requires external circuitry or a different device such as SN74LVC1T45.

How should unused inputs be handled on SN74AHC125QDRG4Q1?

All unused inputs on SN74AHC125QDRG4Q1-including A1–A4 and OE1–OE4-must be permanently tied to either VCC or GND. Floating CMOS inputs cause increased ICC current, unpredictable output states, and potential oscillation due to noise coupling. TI recommends using 10-kΩ pull-up or pull-down resistors for unused OE pins to ensure defined high-Z behavior during power-up.

What is the thermal resistance (RθJA) of SN74AHC125QDRG4Q1 in its SOIC package?

The junction-to-ambient thermal resistance (RθJA) for SN74AHC125QDRG4Q1 in the SOIC (D) package is 86°C/W under standard JEDEC JESD51-2 conditions (single-layer 1-in² copper pad). This value assumes 2-oz copper, no internal planes, and natural convection. For sustained 5-V operation with all four buffers switching at 10 MHz, peak die temperature remains below 110°C at 85°C ambient-well within the 125°C limit.

Is SN74AHC125QDRG4Q1 pin-compatible with standard SN74AHC125 devices?

Yes, SN74AHC125QDRG4Q1 shares identical pinout, electrical characteristics, and functional behavior with the commercial-grade SN74AHC125, including the same SOIC-14 footprint and logic diagram. The "Q1" suffix denotes AEC-Q100 qualification and enhanced process controls, but no physical or functional changes affect PCB layout or firmware integration-enabling drop-in replacement in automotive designs.