Texas Instruments SN74LV125ATRGYR

Overview

SN74LV125ATRGYR from Texas Instruments is a quadruple 3-state bus buffer gate with independent enable-controlled outputs, operating at 4.5–5.5 V, delivering 3.8 ns typical propagation delay at 5 V, TTL-compatible inputs, and Ioff partial-power-down support - used in bidirectional data bus isolation and level translation in industrial control backplanes.

For engineers reviewing the SN74LV125ATRGYR datasheet, SN74LV125ATRGYR pinout, SN74LV125ATRGYR application, or SN74LV125ATRGYR equivalent, this page delivers verified electrical specs, VQFN-14 package layout, functional mode behavior, real-world use cases, and validated alternative options for bus interface design.

Technical Context

The SN74LV125ATRGYR implements four independent non-inverting buffers, each with active-low 3-state output enable (OE), supporting mixed-mode voltage operation across input/output ports. Its Ioff circuitry blocks current flow during power-down, enabling safe hot-insertion in multi-rail systems.

It features low ground bounce (VOLP < 0.8 V) and undershoot immunity (VOHV > 2.3 V) at 5 V, ensuring signal integrity in high-speed digital interfaces. The device meets JESD17 latch-up performance (>250 mA) and supports –40°C to +125°C operation with 47°C/W junction-to-ambient thermal resistance in its RGY package.

Key Specifications

Pinout & Package

VQFN-14 (RGY) package: 3.5 mm × 3.5 mm body, 0.5 mm pitch, exposed thermal pad, 1 mm max height - optimized for space-constrained PCBs requiring efficient heat dissipation via soldered thermal pad.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV125ATRGYR, SN74LVC125APWR offers faster speed at 3.3 V but fails 5-V interoperability and power-down safety; 74LVX125M matches voltage and Ioff specs but sacrifices thermal efficiency and board area - making SN74LV125ATRGYR optimal for compact, thermally demanding 5-V industrial interfaces.

Availability

SN74LV125ATRGYR is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, automated test equipment, and medical imaging interfaces requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant VQFN packaging.

Supply support for SN74LV125ATRGYR 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 industrial, automotive, and communications markets.

The SN74LV125ATRGYR belongs to TI's LV logic family - designed specifically for high-speed, low-power 5-V bus interface applications demanding robust noise immunity, mixed-voltage compatibility, and safe partial-power-down operation.

FAQ

What is the maximum clock frequency supported by SN74LV125ATRGYR in a data bus application?

The SN74LV125ATRGYR is not a clocked device but a combinational buffer; its 3.8 ns typical propagation delay at 5 V supports reliable operation in bus systems with ≤100 MHz toggle rates. For synchronous timing, designers must account for worst-case tpd of 8.5 ns (–40°C to +125°C, CL = 15 pF) when calculating setup/hold margins in their system timing budget. SN74LV125ATRGYR does not impose a hard clock limit but constrains maximum data rate based on trace length and load capacitance.

Does SN74LV125ATRGYR require external pull-up resistors on its OE pins?

Yes - to ensure outputs remain in high-impedance state during power-up or brownout, each OE pin (1OE–4OE) must be tied to VCC via an external pull-up resistor. TI recommends values between 10 kΩ and 100 kΩ, selected based on the driving source's current-sinking capability and required rise time. Leaving OE pins floating risks undefined output states and potential bus contention. SN74LV125ATRGYR's internal circuitry does not include weak pull-ups.

Can SN74LV125ATRGYR interface between 3.3-V and 5-V logic domains?

Yes - SN74LV125ATRGYR supports mixed-mode voltage operation: inputs accept 0–5.5 V regardless of VCC, and outputs swing rail-to-rail (0 to VCC). When powered at 5 V, it safely accepts 3.3-V inputs (VIH = 2 V min) and drives 5-V-tolerant receivers. However, it cannot drive true 3.3-V-only inputs without level shifting, since its 5-V outputs exceed 3.3-V VIH absolute maximum ratings. SN74LV125ATRGYR is ideal for 5-V-centric systems with 3.3-V signal sources.

What is the purpose of the exposed thermal pad on the SN74LV125ATRGYR VQFN package?

The exposed thermal pad on SN74LV125ATRGYR's RGY package must be soldered to a PCB copper pour to achieve its rated 47°C/W junction-to-ambient thermal resistance. Without proper thermal pad connection, RθJA degrades significantly (to ~100°C/W or worse), risking thermal shutdown or accelerated parametric drift above 70°C ambient. TI literature SLUA271 specifies minimum 80% solder coverage and dedicated thermal vias to inner ground planes. SN74LV125ATRGYR's reliability and sustained 16-mA output drive depend on this thermal path.

How does the Ioff feature of SN74LV125ATRGYR protect downstream circuitry during power-down?

SN74LV125ATRGYR's Ioff circuitry actively disables input and output structures when VCC = 0 V, limiting leakage current to ≤5 µA even with input/output voltages up to 5.5 V applied. This prevents damaging back-current flow from live buses into a powered-down subsystem - critical for hot-plug architectures like modular PLCs or server backplanes. Unlike passive isolation, Ioff is an integrated silicon feature; no external components are needed. SN74LV125ATRGYR maintains this protection across its full –40°C to +125°C temperature range.