Texas Instruments SN74LVC1G125DRLR

Overview

SN74LVC1G125 from Texas Instruments is a single 3-state bus buffer gate used for signal isolation and controlled data routing on low-voltage digital buses. It features true noninverting logic, 3.3V/5V supply compatibility (1.65–5.5V), ±24mA output drive at 3.3V, 3.7ns max propagation delay, and Ioff support for live insertion in partial-power-down systems.

For engineers reviewing the SN74LVC1G125 datasheet, SN74LVC1G125 pinout, SN74LVC1G125 application, or SN74LVC1G125 equivalent, key selection criteria include 3-state control timing (ten/tdis ≤ 5.6ns at 3.3V), overvoltage-tolerant inputs (up to 5.5V), ultra-small SOT-5X3 (DRL) package (1.45mm × 1.2mm), and guaranteed operation from –40°C to 125°C.

Technical Context

The SN74LVC1G125 implements a CMOS-based noninverting buffer with active-low 3-state enable (OE). Its output transitions between driven HIGH/LOW states and high-impedance (Z) based solely on OE logic level - no internal latching or clocking. The device uses standard CMOS input structure with overvoltage tolerance and balanced push-pull output stage capable of sourcing/sinking equal current.

It supports mixed-voltage interfacing via down-translation: inputs accept up to 5.5V regardless of VCC (1.65–5.5V), enabling reliable 5V-to-3.3V signal conditioning without external level shifters. Ioff circuitry ensures zero current flow when VCC = 0V, protecting back-driven outputs during hot-swap or power sequencing.

Key Specifications

Pinout & Package

SOT-5X3 (DRL) package: 5-pin, 1.45mm × 1.2mm body, 0.5mm pitch, exposed pad optional. Compact footprint ideal for space-constrained PCBs in portable and embedded systems.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC1G125, SN74LVC1G126DRYR provides functional inversion at identical speed and drive, while NC7SZ125P5X trades 33% lower output current and 2× higher quiescent current for broader distributor availability - both require layout review due to different packages and drive margins.

Availability

SN74LVC1G125 is available at Aetrix Electronics and suitable for motor control interfaces, SSD power sequencing, video infrastructure backplanes, and military radar data acquisition requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVC1G125 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 for industrial, automotive, and communications markets.

The SN74LVC1G125 belongs to TI's LVC low-voltage CMOS logic family, designed specifically for space-constrained, mixed-voltage digital systems requiring robust 3-state control, wide operating temperature, and hot-swap reliability.

FAQ

What is the recommended pull-up resistor value for OE on SN74LVC1G125?

The OE pin must be pulled up to VCC to ensure high-impedance state at power-up. TI specifies minimum resistance based on driver sink capability: for VCC = 3.3V and IOH = 24mA, a 10kΩ resistor is typical and sufficient. Lower values (e.g., 4.7kΩ) improve noise immunity but increase static current; values above 100kΩ risk slow edge rates. Always verify against actual OE leakage in your thermal environment. SN74LVC1G125 datasheet Section 7.1 confirms this requirement.

Does SN74LVC1G125 support 5V input signals when powered at 1.8V?

Yes. SN74LVC1G125 inputs are overvoltage tolerant up to 5.5V regardless of VCC level (1.65–5.5V). When VCC = 1.8V, VIH(min) = 0.65 × VCC = 1.17V and VIL(max) = 0.35 × VCC = 0.63V - fully compatible with 5V TTL logic thresholds. This eliminates external level shifters in 5V-to-1.8V translation. SN74LVC1G125 Electrical Characteristics Table 5.3 explicitly defines this behavior.

Can SN74LVC1G125 drive a 50pF load while maintaining 3.7ns propagation delay?

No. The 3.7ns tpd is specified at CL = 15pF (Section 5.6). At CL = 50pF, SN74LVC1G125 propagation delay increases to ≤4.7ns (Section 5.8, –40°C to 125°C). For 50pF loads, TI recommends verifying timing margins in worst-case conditions and adding series damping resistors if ringing occurs. SN74LVC1G125 Application Section 8.2.1.1 confirms 50pF as maximum load for full spec compliance.

Is SN74LVC1G125 pin-compatible with other SOT-5X3 logic devices?

SN74LVC1G125 uses the standard 5-pin SOT-5X3 (DRL) footprint defined by JEDEC MO-252, making it mechanically compatible with other DRL-packaged TI logic (e.g., SN74LVC1G00, SN74LVC1G08). However, pin functions differ: A/OE/Y/GND/VCC assignment is specific to SN74LVC1G125. Substitution requires verification of logic function, drive strength, and timing - not just pin count or package. SN74LVC1G125 Pin Configuration Figure 4 confirms this layout.

What is the maximum junction temperature for SN74LVC1G125 during continuous operation?

The absolute maximum junction temperature (TJ) for SN74LVC1G125 is 150°C, per Absolute Maximum Ratings Table 5.1. Continuous operation must stay below this limit. Using RθJA = 364.1°C/W (DRL package), maximum allowable power dissipation at TA = 125°C is ~69mW. Derating curves in Figure 5-1 show tpd increases only marginally up to 125°C ambient - confirming suitability for high-temp environments. SN74LVC1G125 Thermal Information Table 5.4 provides full derating guidance.