STMicroelectronics 74LCX541TTR

Overview

74LCX541TTR from STMicroelectronics is a low-voltage CMOS octal non-inverting 3-state bus buffer with 5V-tolerant inputs and outputs, operating from 2.0V to 3.6V supply, delivering 8.0 ns max propagation delay at VCC = 3.0–3.6V, ±24 mA output drive, and symmetrical output impedance for PCI bus-level interfacing in 3.3V systems with 5V signal compatibility.

For engineers reviewing the 74LCX541TTR datasheet, 74LCX541TTR pinout, 74LCX541TTR application, or 74LCX541TTR equivalent, key selection criteria include 5V tolerance on all I/Os, dual enable logic (G1/G2 ANDed), high-impedance state control timing (tPZL/tPLZ ≤ 7.5 ns), and TSSOP-20 package suitability for space-constrained 3.3V/5V mixed-signal PCB layouts.

Technical Context

The device implements an octal non-inverting buffer with dual active-low 3-state enable inputs (G1, G2) requiring both low to activate outputs; outputs enter high-impedance when either enable is high. It uses sub-micron C2MOS technology enabling 3.3V operation with AC/ACT-speed performance and reduced power versus 5V families.

Input and output protection includes 2 kV HBM ESD immunity and latch-up resistance >500 mA per JESD17. All I/O pins tolerate 0–5.5 V regardless of VCC, supporting hot-swap and mixed-voltage domain interfacing without level shifters.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, thin profile (1.05 mm max height), lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LVC541APW and SN74LVC8T245RHLR, the 74LCX541TTR uniquely delivers guaranteed 5V-tolerant I/O with PCI-compliant drive strength and dual-enable control - critical for fixed-direction, mixed-voltage, high-reliability backplane interfaces where level translation overhead must be eliminated.

Availability

74LCX541TTR is available at Aetrix Electronics and suitable for PCI local bus interfaces, 3.3V/5V mixed-voltage backplanes, and low-power embedded memory expansion requiring stable component supply and long-term industrial lifecycle support.

Supply support for 74LCX541TTR 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, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer applications.

The 74LCX logic family targets high-speed, low-voltage 3.3V systems requiring interoperability with 5V environments - optimized for PCI, memory expansion, and mixed-signal interface consolidation without external level shifters.

FAQ

Is 74LCX541TTR pin-compatible with standard 74LS541 or 74HC541?

Yes - it is pin- and function-compatible with the 74 series 541 family in TSSOP-20 packaging. Input/output assignments (A1–A8, Y1–Y8, G1/G2, VCC, GND) match exactly, and truth table behavior is identical. However, VCC range and I/O voltage tolerance differ significantly: 74LCX541TTR operates at 2.0–3.6V and tolerates 0–5.5V on all I/Os, unlike 74LS541 (4.75–5.25V only) or 74HC541 (no 5V tolerance).

What is the maximum recommended operating temperature for continuous use?

The 74LCX541TTR is rated for continuous operation from –55 °C to +125 °C ambient temperature. This extended range is validated per JEDEC JESD78 and supported by its latch-up immunity (>500 mA) and robust ESD protection (2 kV HBM). Industrial and automotive under-hood applications must ensure PCB thermal design maintains junction temperature below 150 °C per absolute maximum ratings.

Can G1 and G2 be tied together for single-enable operation?

Yes - G1 and G2 may be connected to a common control signal. Since both are active-low enables ANDed internally, tying them together preserves correct 3-state behavior: low enables outputs, high disables all eight buffers. No external logic is needed, and this configuration maintains full timing specifications including tPZL (≤7.5 ns) and tPLZ (≤7.5 ns) at VCC = 3.0–3.6V.

Does 74LCX541TTR require external pull-up or pull-down resistors on unused inputs?

No - unused inputs (A1–A8, G1, G2) may be left floating only if permanently driven by a known logic state elsewhere in the system. For robustness, STMicroelectronics recommends connecting unused inputs to VCC or GND via 10 kΩ resistors. Floating enables risk increased ICC due to input stage metastability and potential ESD-induced latch-up; the device's ±5 µA input leakage does not eliminate this risk in noisy or high-impedance environments.