Texas Instruments SN74HCT541NSRE4

Overview

SN74HCT541NSRE4 from Texas Instruments is an octal buffer and line driver IC with 3-state outputs, designed for bus interface and signal isolation in 5-V digital systems. It operates from 4.5 V to 5.5 V, delivers ±6 mA output drive at 5 V, exhibits 12 ns typical propagation delay, and supports up to 15 LSTTL loads - commonly used in microcontroller I/O expansion and memory address/data bus buffering.

For engineers reviewing the SN74HCT541NSRE4 datasheet, SN74HCT541NSRE4 pinout, SN74HCT541NSRE4 application, or SN74HCT541NSRE4 equivalent, key selection criteria include 3-state control architecture (dual OE inputs), TTL-compatible inputs, low 80-µA max ICC quiescent current, and SO package thermal performance (RθJA = 113.4 °C/W).

Technical Context

The SN74HCT541NSRE4 implements eight independent non-inverting buffers, each with true output logic and dual 3-state enable inputs (OE1 and OE2) wired as a 2-input NOR gate - enabling simultaneous high-impedance control of all outputs when either OE is high. Its HCT logic family ensures TTL-voltage compatibility while maintaining CMOS power efficiency.

It features data flow-through pinout (inputs on one side, outputs on the opposite side), reducing PCB trace crossovers and simplifying layout in dense bus architectures. The device is specified across –40°C to +85°C and supports CL = 50 pF and 150 pF load conditions with validated switching characteristics including tpd, ten, tdis, and tt.

Key Specifications

Pinout & Package

SOP (NS) package, 20-pin, 15.00 mm × 5.30 mm body size, 1.27 mm lead pitch, gull-wing leads, RoHS-compliant NIPDAU finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT240N and SN74LV541APWR, the SN74HCT541NSRE4 provides true (non-inverting) output logic in a widely available SO package with proven 5-V bus drive strength - making it optimal for drop-in upgrades of legacy 5-V systems where signal polarity must be preserved and layout reuse is critical.

Availability

SN74HCT541NSRE4 is available at Aetrix Electronics and suitable for industrial PLC modules, microcontroller I/O expansion, memory bus buffering, and legacy system interface applications requiring stable component supply and long-term manufacturability.

Supply support for SN74HCT541NSRE4 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The SN74HCT541NSRE4 belongs to TI's legacy HCT logic family, engineered specifically for robust 5-V TTL-compatible interfacing in cost-sensitive, high-reliability industrial control and instrumentation systems.

FAQ

What is the operating temperature range for the SN74HCT541NSRE4?

The SN74HCT541NSRE4 is rated for operation from –40°C to +85°C, meeting industrial-grade environmental requirements. This range is validated per TI's recommended operating conditions and applies to the SO (NS) package variant. Thermal derating is required above 70°C ambient if power dissipation exceeds limits defined by RθJA = 113.4 °C/W.

Does the SN74HCT541NSRE4 support 3.3-V input logic levels?

No, the SN74HCT541NSRE4 does not reliably recognize 3.3-V logic levels as valid high inputs. Its VIH minimum is 2.0 V at VCC = 4.5–5.5 V, but 3.3-V CMOS outputs may fall below this threshold under worst-case conditions. For 3.3-V system interfacing, use SN74LV541APWR or add level-shifting circuitry before the SN74HCT541NSRE4 inputs.

How are the two output-enable inputs (OE1 and OE2) logically combined in the SN74HCT541NSRE4?

The SN74HCT541NSRE4 uses a 2-input NOR gate to combine OE1 and OE2: all eight outputs enter high-impedance state if either OE1 or OE2 is high; outputs are enabled only when both OE1 and OE2 are low. This architecture supports redundant enable control or OR-type bus arbitration in multi-controller systems.

Can unused inputs on the SN74HCT541NSRE4 be left floating?

No, unused inputs on the SN74HCT541NSRE4 must be tied to VCC or GND. Floating inputs cause undefined internal node voltages, leading to increased ICC, erratic output states, or excessive power consumption. TI explicitly recommends connecting all unused A1–A8 and OE1/OE2 inputs to a defined logic level per Section 5.2 of the datasheet.

What is the maximum capacitive load the SN74HCT541NSRE4 can drive while maintaining specified timing?

The SN74HCT541NSRE4 is characterized for CL = 50 pF and CL = 150 pF loads. At 50 pF, tpd is 12 ns (typical); at 150 pF, tpd increases to 19 ns (typical). Driving loads beyond 150 pF risks violating setup/hold timing in synchronous systems and may require series termination or reduced clock rates - verify with actual board parasitics using TI's switching characteristic curves.