STMicroelectronics 74LX1G125STR

Overview

74LX1G125STR from STMicroelectronics is a single 3-state bus buffer IC designed for voltage-level translation and bus isolation in low-power portable systems. It operates across 1.65V–5.5V supply, delivers 4.7ns max propagation delay at 3V, supports 5V-tolerant inputs, and provides symmetrical ±24mA drive capability at VCC = 3V. It is used in smartphone baseband interfaces and digital camera I/O expansion.

For engineers reviewing the 74LX1G125STR datasheet, 74LX1G125STR pinout, 74LX1G125STR application, or 74LX1G125STR equivalent, key selection criteria include 3-state enable timing (tPLZ/tPZL ≤ 6.0ns), power-down input/output protection, 1.65V minimum operating voltage, and SOT23-5L package compatibility with high-density PCB layouts.

Technical Context

This CMOS buffer implements a single non-inverting data path with active-high 3-state enable (1G). Its sub-micron C2MOS process enables operation down to 1.65V while retaining 5V-tolerant inputs-critical for mixed-voltage interconnects between 3.3V/2.5V logic and legacy 5V peripherals.

The device features power-down protection that allows safe 0–7V input voltages regardless of VCC state, and symmetrical output drive (|IOH| = |IOL| ≥ 24mA at 3V) ensures matched rise/fall times and balanced bus loading in bidirectional data paths.

Key Specifications

Pinout & Package

SOT23-5L package: 5-pin surface-mount, 2.8mm × 1.5mm footprint, 1.45mm max height, lead pitch 0.95mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC1G125DBVR and NC7SZ125P5X, the 74LX1G125STR uniquely combines 7V input tolerance, 1.65V minimum VCC, and sub-5ns delay-making it the only option for robust 5V-to-1.8V bidirectional bus isolation without auxiliary components.

Availability

74LX1G125STR is available at Aetrix Electronics and suitable for smartphone baseband interfaces, digital still camera I/O expansion, and PDA memory card slot control requiring stable component supply and long-term lifecycle support.

Supply support for 74LX1G125STR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering silicon solutions for automotive, industrial, and consumer markets since 1987.

The 74LX series targets ultra-low-power portable electronics, emphasizing voltage flexibility, ESD robustness, and sub-micron CMOS efficiency for battery-constrained applications like smartphones and digital cameras.

FAQ

Can 74LX1G125STR operate with VCC = 1.65V while driving a 24mA load?

No. At VCC = 1.65V, the guaranteed output drive is ±4mA (per AC specs), not ±24mA. The ±24mA rating applies only at VCC = 3.0–3.6V. Operating at 1.65V requires load reduction to ≤4mA to meet VOL/VOH specifications and avoid excessive voltage drop.

Is the 74LX1G125STR pin-compatible with standard SOT23-5L logic buffers like 74LVC1G125?

Yes-pinout matches industry-standard SOT23-5L: Pin 1 = OE, Pin 2 = A, Pin 3 = GND, Pin 4 = Y, Pin 5 = VCC. Mechanical dimensions and solder pad layout are identical, enabling drop-in replacement in existing footprints.

Does the power-down protection cover both input and output pins simultaneously when VCC = 0V?

Yes. All five pins-including 1A, 1G, 1Y, GND, and VCC-feature diode-based protection that blocks reverse current flow and prevents latch-up when VCC is unpowered, even with 5.5V applied to any I/O pin.

What is the maximum data rate supported by 74LX1G125STR in a 50Ω transmission line environment?

Based on tPD = 4.7ns (max) and balanced edge rates, the device supports NRZ data rates up to ~100Mbps in point-to-point configurations. For reliable eye opening, limit trace length to <10cm and maintain controlled impedance to avoid reflections degrading tPLZ/tPZL timing margins.