Texas Instruments SN74LVC126APWR

Overview

SN74LVC126APWR from Texas Instruments is a quadruple 3-state bus buffer gate operating from 1.65 V to 3.6 V, featuring 5.5 V-tolerant inputs, 4.7 ns max propagation delay at 3.3 V, and –40°C to +125°C temperature range. It serves as a level-translating buffer in mixed-voltage digital interfaces, such as between 3.3 V microcontrollers and 5 V peripherals in consumer audio systems.

For engineers reviewing the SN74LVC126APWR datasheet, SN74LVC126APWR pinout, SN74LVC126APWR application, or SN74LVC126APWR equivalent, key selection criteria include 3-state output control timing (ten/tdis), input overvoltage tolerance, drive strength (24 mA at 3 V), thermal performance in TSSOP-14, and compatibility with high-speed digital buses up to 100 MHz.

Technical Context

The SN74LVC126APWR implements four independent non-inverting buffers, each with dedicated active-low output-enable (OE) control. Its CMOS design supports rail-to-rail output swing (VOL ≤ 0.8 V, VOH ≥ VCC – 0.3 V) and exhibits low dynamic power consumption (Cpd = 22 pF at 3.3 V, 10 MHz).

Each buffer operates under true 3-state logic: output is high-impedance when OE is low; otherwise, Y = A. Input voltage tolerance up to 5.5 V enables reliable down-translation from 5 V logic into 1.65–3.6 V domains without external level shifters.

Key Specifications

Pinout & Package

TSSOP-14 (PW) package: 5.00 mm × 4.40 mm body size, 14-pin surface-mount, lead-free NiPdAu finish, moisture sensitivity level (MSL) 1, rated for reflow up to 260°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC126APWR, SN74LVC125APWR offers identical performance but demands OE polarity adaptation in firmware, while 74LVC126PW,118 provides cost parity but lacks full industrial temperature certification - making SN74LVC126APWR the optimal choice for thermally demanding, safety-critical, or long-lifecycle deployments.

Availability

SN74LVC126APWR is available at Aetrix Electronics and suitable for audio docking stations, solid-state drive controllers, HDMI CEC subsystems, and industrial PLC I/O expansion requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVC126APWR 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 connectivity technologies, with decades of expertise in logic IC design and automotive-grade qualification.

The SN74LVC126APWR belongs to TI's LVC (Low-Voltage CMOS) logic family, engineered for high-speed, low-power, mixed-voltage interoperability in consumer, industrial, and automotive digital systems.

FAQ

What is the maximum clock frequency supported by SN74LVC126APWR in a data path?

The SN74LVC126APWR has a maximum propagation delay (tpd) of 4.7 ns at VCC = 3.3 V and TA = 25°C. This corresponds to a theoretical maximum toggle rate of ~106 MHz in a single-ended path. In practice, SN74LVC126APWR reliably supports data buses up to 100 MHz when loaded with ≤15 pF and routed with controlled impedance, as confirmed in TI's application notes for LVC-family timing analysis.

Can SN74LVC126APWR safely interface a 5 V microcontroller GPIO to a 3.3 V FPGA input?

Yes - SN74LVC126APWR accepts input voltages up to 5.5 V regardless of VCC, making it ideal for down-translation. When VCC = 3.3 V, the SN74LVC126APWR outputs swing rail-to-rail (VOH ≥ 3.0 V, VOL ≤ 0.3 V), fully satisfying 3.3 V LVTTL input thresholds. No external resistors or clamps are needed, provided the 5 V source drives within SN74LVC126APWR's input current limits (±20 µA max).

How should unused OE pins be handled on SN74LVC126APWR?

All unused OE pins on SN74LVC126APWR must be tied to GND through a pulldown resistor (typically 10 kΩ) to guarantee high-impedance output states during power-up, power-down, or floating conditions. Leaving OE pins unconnected risks undefined output behavior and potential bus contention. TI specifies this requirement explicitly in Section 7.4 of the SN74LVC126APWR datasheet to ensure robust system-level reliability.

Does SN74LVC126APWR require external bypass capacitors, and where should they be placed?

Yes - SN74LVC126APWR requires a 0.1 µF ceramic bypass capacitor placed directly between VCC (pin 14) and GND (pin 7), with trace length ≤2 mm. This placement minimizes inductance and suppresses supply noise generated by fast output transitions. For systems with multiple logic devices, add a bulk 1 µF capacitor nearby. Failure to implement proper decoupling may cause VOL/VOH violations or erratic 3-state behavior, especially at high frequencies.

Is SN74LVC126APWR pin-compatible with other TSSOP-14 logic buffers from Texas Instruments?

SN74LVC126APWR is mechanically pin-compatible with other TI TSSOP-14 logic devices (e.g., SN74LVC125APWR, SN74LVC138APWR), sharing identical 0.65 mm pitch and 5.00 mm × 4.40 mm footprint. However, functional pinout differs: SN74LVC126APWR uses active-low OE on pins 1/4/10/13, whereas SN74LVC125APWR uses active-high OE. Electrical compatibility requires verifying OE polarity, drive strength, and timing alignment before substitution.