STMicroelectronics 74LVQ125TTR

Overview

74LVQ125TTR from STMicroelectronics is a low-voltage CMOS quad 3-state bus buffer with pin- and function-compatibility to 74-series 125 devices. It operates from 2.0 V to 3.6 V, delivers symmetrical output drive (±12 mA min at 3.0 V), supports 75 Ω transmission line driving, and achieves 5 ns typical propagation delay at 3.3 V - ideal for noise-sensitive 3.3 V digital interconnects in industrial control backplanes.

For engineers reviewing the 74LVQ125TTR datasheet, 74LVQ125TTR pinout, 74LVQ125TTR application, or 74LVQ125TTR equivalent, key selection criteria include guaranteed PCI bus levels at 24 mA, balanced tPLH/tPHL delays, 0.3 V typical dynamic quiet output noise (VOLP), 4 µA max ICC quiescent current, and ESD immunity up to 2 kV - all validated across –55 °C to +125 °C.

Technical Context

The 74LVQ125TTR implements four independent non-inverting buffers, each with a dedicated active-low 3-state enable input (1G–4G). All outputs enter high-impedance state when the corresponding G input is high, enabling bidirectional bus arbitration without external logic.

Its C2MOS sub-micron silicon gate process ensures latch-up immunity and rail-to-rail input compatibility (VIH = 2.0 V min, VIL = 0.8 V max over full VCC range), while symmetrical |IOH|/IOL drive and 0.3 V typical VOLP support clean signal integrity on stubbed or unterminated 75 Ω lines.

Key Specifications

Pinout & Package

TSSOP-14 package (JEDEC MO-153, 4.4 mm × 5.0 mm body, 0.65 mm pitch) with exposed pad not electrically connected; compliant with tape-and-reel packaging per Table 10 mechanical data.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC125APWR and 74AUP1G125GW,125, the 74LVQ125TTR uniquely balances low noise (0.3 V VOLP), industrial temperature range, and quad integration - making it optimal for deterministic 3.3 V bus architectures where signal integrity and thermal robustness are prioritized over minimum ICC or smallest footprint.

Availability

74LVQ125TTR is available at Aetrix Electronics and suitable for industrial backplane interconnect, PCI bus signal buffering, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74LVQ125TTR 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, designing and manufacturing analog, digital, and mixed-signal ICs for industrial, automotive, and consumer markets.

The 74LVQ series targets low-voltage, low-noise digital interface applications - specifically engineered to replace legacy 74HC/HCT families in 3.3 V systems while preserving pinout, logic function, and timing behavior.

FAQ

Is the 74LVQ125TTR compatible with 5 V TTL inputs?

Yes - its input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) are fully compatible with standard TTL output levels (VOH ≥ 2.4 V, VOL ≤ 0.4 V), allowing direct connection to 5 V TTL sources without level shifters. Input protection diodes clamp voltages to safe limits, and absolute maximum ratings permit VI up to VCC + 0.5 V.

What is the maximum capacitive load this device can drive reliably?

The 74LVQ125TTR is characterized for CL = 50 pF in AC specifications, and its 12 mA output drive supports stable operation into ≥75 Ω transmission lines. For lumped capacitive loads beyond 50 pF, propagation delay increases linearly (tPD ∝ CL); design margin requires limiting total trace + load capacitance to ≤75 pF for timing-critical 33 MHz applications.

Does the TSSOP-14 package require thermal vias or special PCB layout?

No thermal vias are required - the TSSOP-14 has low thermal resistance (θJA ≈ 140 °C/W) and dissipates <10 mW under typical operation. However, a solid ground plane beneath the package and 100 nF ceramic decoupling capacitor placed within 5 mm of VCC/GND pins are mandatory to suppress VOLP noise and maintain 5 ns timing accuracy.

Can unused buffer channels be left floating?

No - all unused inputs (A and G pins) must be tied to VCC or GND. Floating G inputs cause indeterminate output states and increase ICC; floating A inputs raise susceptibility to noise-induced switching and ESD coupling. Per datasheet Table 5, recommended operating conditions require defined logic levels on all inputs at all times.