Texas Instruments CD74HCT126M96G4

Overview

CD74HCT126M96G4 from Texas Instruments is a quadruple non-inverting buffer with 3-state outputs, designed for bus interface and signal gating in digital systems. It operates across 4.5 V to 5.5 V supply voltage, supports –55°C to +125°C industrial/military temperature range, delivers propagation delay ≤25 ns at 5 V (CL = 50 pF), and drives up to 10 LSTTL loads. It is used to enable/disable data paths on shared buses in microcontroller peripherals and memory interfaces.

For engineers reviewing the CD74HCT126M96G4 datasheet, CD74HCT126M96G4 pinout, CD74HCT126M96G4 application, or CD74HCT126M96G4 equivalent, key selection criteria include 3-state output timing consistency, high-temperature operation capability, TTL-compatible input thresholds, and SOIC-14 package compatibility with legacy board layouts.

Technical Context

This device implements four independent positive-logic buffers (Y = A) with active-low 3-state enable inputs (OE). Each channel features balanced CMOS outputs capable of sourcing/sinking ±6 mA at 4.5 V while maintaining VOH ≥ 3.98 V and VOL ≤ 0.33 V under load.

It uses standard CMOS inputs with VIH = 2.0 V (min) and VIL = 0.8 V (max) at VCC = 4.5 V, ensuring direct compatibility with TTL logic families. The device includes internal clamp diodes on all I/O pins and supports fanout to 10 LSTTL loads without external buffering.

Key Specifications

Pinout & Package

CD74HCT126M96G4 is housed in a 14-pin SOIC (D) package measuring 8.70 mm × 3.90 mm with standard 1.27-mm pitch. Pin 1 is marked by a beveled corner or dot; the package is RoHS-compliant with NiPdAu (NIPDAU) lead finish and MSL Level-1 rating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buffer-with-3-state-output applications.

Compared with SN74HCT125DR and 74LVC126APW,118, CD74HCT126M96G4 uniquely combines non-inverting logic, 5-V TTL compatibility, and extended temperature range in a standard SOIC-14 footprint-making it the only option for drop-in replacement in legacy industrial controllers requiring polarity fidelity and wide thermal margin.

Availability

CD74HCT126M96G4 is available at Aetrix Electronics and suitable for industrial bus interface, microcontroller peripheral expansion, memory address latching, and military data acquisition systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HCT126M96G4 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 90 years of innovation in high-reliability components.

CD74HCT126M96G4 belongs to TI's HCT logic family, engineered specifically for seamless TTL-to-CMOS interfacing in harsh-environment digital systems where signal integrity, timing predictability, and temperature resilience are critical.

FAQ

What is the maximum capacitive load supported by CD74HCT126M96G4?

CD74HCT126M96G4 is characterized for operation with ≤50 pF total load capacitance (including trace and input capacitance) at 5 V supply. While it can drive up to 70 pF in practice, exceeding 50 pF increases propagation delay and transition time beyond datasheet limits-potentially causing timing violations in 20-MHz+ bus systems. For heavier loads, add a series resistor to limit peak output current per TI's layout guidelines.

Does CD74HCT126M96G4 support mixed-voltage operation between 3.3 V and 5 V domains?

No, CD74HCT126M96G4 is strictly a 4.5–5.5 V device and does not support 3.3-V operation. Its input thresholds (VIH = 2.0 V min at 4.5 V) are TTL-compatible but not guaranteed for 3.3-V logic levels. Interfacing with 3.3-V controllers requires external level-shifting circuitry or a dual-supply buffer such as SN74AVCH16T245. Using CD74HCT126M96G4 directly with 3.3-V signals risks unreliable switching or increased static current.

How should unused inputs and outputs be handled on CD74HCT126M96G4?

Unused inputs on CD74HCT126M96G4 must be tied to VCC or GND-never left floating-to prevent undefined logic states and excessive supply current. Unused outputs may be left unconnected (floating) since they enter high-impedance state when their OE is inactive. TI recommends 10-kΩ pull-up/down resistors for unused inputs if default logic state must be maintained during partial system power-down, as confirmed in Section 9.2.1.2 of the CD74HCT126M96G4 datasheet.

Is CD74HCT126M96G4 pin-compatible with CD74HC126 variants?

Yes, CD74HCT126M96G4 shares identical SOIC-14 pinout and terminal functions with CD74HC126M and CD74HC126M96, including pin assignments for VCC (14), GND (7), and all channel-specific A/OE/Y signals. However, HCT logic has TTL-compatible input thresholds while HC logic uses CMOS thresholds-so direct substitution affects noise immunity and interfacing behavior. Always verify input voltage compatibility before replacing CD74HC126M96 with CD74HCT126M96G4 in existing designs.

What thermal derating applies to CD74HCT126M96G4 in high-temperature operation?

CD74HCT126M96G4 has a junction-to-ambient thermal resistance (RθJA) of 133.6°C/W in SOIC-14 package. At maximum ambient temperature (125°C), allowable power dissipation drops to ~0.56 mW assuming TJ(max) = 150°C. In practice, typical ICC remains below 160 µA, resulting in <1 mW total power-well within safe limits. No heatsinking is required, but ensure ≥25% copper pour under the package and avoid placing near heat-generating components to maintain margin.