Texas Instruments SN74LV126ADR

Overview

SN74LV126ADR from Texas Instruments is a quadruple bus buffer gate with independent 3-state outputs, designed for 2V to 5.5V VCC operation. It features 6.5ns maximum propagation delay at 5V, Ioff support for live insertion and partial power-down, and 5.5V-tolerant inputs enabling mixed-mode voltage translation in bus interface applications such as server backplanes and network switch data paths.

For engineers reviewing the SN74LV126ADR datasheet, SN74LV126ADR pinout, SN74LV126ADR application, or SN74LV126ADR equivalent, this device serves as a low-power, high-noise-immunity bus driver where controlled output enable sequencing, ground bounce mitigation (<0.8V at 3.3V), and latch-up immunity (>250mA per JESD17) are critical selection criteria.

Technical Context

The SN74LV126ADR implements four independent noninverting buffers, each with dedicated active-high output-enable (OE) control. Each channel transitions to high-impedance when its OE is low, and passes A→Y when OE is high - supporting isolated bus segment control without contention.

Its CMOS design supports down-translation (e.g., 5V inputs to 3.3V VCC), exhibits balanced rise/fall times to minimize ringing, and incorporates Ioff circuitry that disables current flow during power-off or partial supply conditions - enabling hot-plug capability and back-drive protection in multi-rail systems.

Key Specifications

Pinout & Package

SN74LV126ADR is packaged in a 14-pin SOIC (D package) with 8.65mm × 6mm footprint and 1.75mm max height, optimized for automated assembly and thermal performance (RθJA = 92.7°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC126A and 74LVX126M, the SN74LV126ADR uniquely supports 5.5V-tolerant inputs across its full 2V–5.5V supply range and includes Ioff and JESD17-compliant latch-up immunity - making it the only option for robust mixed-voltage bus isolation in hot-pluggable infrastructure equipment.

Availability

SN74LV126ADR is available at Aetrix Electronics and suitable for server backplane interface, network switch data path, and electronic point-of-sale terminal applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SN74LV126ADR 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 company delivering analog and embedded processing solutions, with leadership in logic, power management, and signal chain technologies.

The SN74LV126ADR belongs to TI's LV family of low-voltage, high-noise-immunity logic devices, engineered specifically for reliable bus buffering in mixed-supply, hot-pluggable, and electrically harsh environments like telecom infrastructure and industrial computing.

FAQ

What is the maximum propagation delay of the SN74LV126ADR at 5V supply?

The SN74LV126ADR has a maximum propagation delay (tpd) of 6.5ns at VCC = 5V ±0.5V with CL = 15pF and TA = 25°C, as specified in Section 5.8 of the official datasheet. This value represents worst-case delay across process, voltage, and temperature corners and is validated for use in timing-critical bus interface designs.

Does the SN74LV126ADR support 5V input signals when powered from 3.3V?

Yes, the SN74LV126ADR supports 5.5V-tolerant inputs across its entire 2V–5.5V VCC range. When powered from 3.3V, it safely accepts 5V logic levels on all A-input pins without damage or level-shifting circuitry - a key feature confirmed in Section 7.3 and Table 5.3 of the datasheet.

How does the Ioff feature of the SN74LV126ADR improve system reliability?

The Ioff feature of the SN74LV126ADR disables current flow through the device when VCC = 0V, preventing back-driving of powered-down sections and enabling safe live insertion. This is explicitly verified per JEDEC JESD78 and supports partial power-down modes in multi-rail systems - a capability documented in Section 1 and Table 5.5 of the SN74LV126ADR datasheet.

What is the recommended pull-down resistor value for OE pins on the SN74LV126ADR during power-up?

The SN74LV126ADR datasheet recommends tying each OE pin to GND through a pulldown resistor to ensure high-impedance state at power-up. The minimum resistor value depends on the current-sourcing capability of the driving source; TI specifies that the resistor must limit current to within the OE pin's absolute maximum input current rating (±20mA), typically resulting in values between 1kΩ and 10kΩ in practice.

Is the SN74LV126ADR pin-compatible with the SN74LVC126A?

No, the SN74LV126ADR is not pin-compatible with the SN74LVC126A. Although both are 14-pin SOIC bus buffers, their pin functions differ: SN74LV126ADR places OE pins on pins 1, 4, 10, and 13, whereas SN74LVC126A uses pins 1, 2, 9, and 10 for OE - requiring PCB layout changes for substitution.