STMicroelectronics M74HCT541B1R

Overview

M74HCT541B1R from STMicroelectronics is a non-inverting octal bus buffer with 3-state outputs in 20-pin DIP package, featuring 14 ns typical propagation delay at 4.5 V, ±6 mA symmetrical output drive, and TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V). It enables bidirectional bus isolation in industrial control backplanes requiring low-power, high-speed level translation between HCMOS and TTL logic families.

For engineers reviewing the M74HCT541B1R datasheet, M74HCT541B1R pinout, M74HCT541B1R application, or M74HCT541B1R equivalent, key selection criteria include 3-state enable timing (tPZL/tPLZ ≤ 41 ns), quiescent ICC ≤ 4 µA at 25°C, input capacitance ≤ 10 pF, and operation across –55°C to +125°C industrial temperature range.

Technical Context

The M74HCT541B1R implements dual active-high 3-state enable inputs (G1, G2) wired as an AND gate: only when both are high do all eight outputs enter high-impedance state. Its silicon gate C2MOS process ensures compatibility with TTL output voltage levels while maintaining CMOS power efficiency.

Propagation delays tPLH and tPHL are balanced (≤ 35 ns max over full temperature range), and output impedance is symmetrical (|IOH| = IOL ≥ 6 mA), enabling matched rise/fall times and reduced signal distortion on shared data buses.

Key Specifications

Pinout & Package

Package: Plastic DIP-20 (0.25 inch width), 20-pin through-hole, JEDEC MS-001 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 SN74HCT541N and 74VHC541N, the M74HCT541B1R uniquely combines extended temperature support (–55°C), DIP-20 through-hole compatibility, and guaranteed 14 ns propagation at 4.5 V - making it optimal for legacy-replacement and ruggedized embedded designs.

Availability

M74HCT541B1R is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive ECU data bus isolation, and test equipment signal routing requiring stable component supply and long-term obsolescence management.

Supply support for M74HCT541B1R 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, MCU, power, and discrete components for industrial, automotive, and consumer markets.

The M74HCT541B1R belongs to ST's high-speed CMOS logic family, engineered specifically for seamless interoperability between TTL, NMOS, and HCMOS systems in harsh-environment embedded control applications.

FAQ

What is the maximum operating supply voltage for M74HCT541B1R?

The absolute maximum VCC is +7.0 V, but the recommended operating range is strictly 4.5 V to 5.5 V per datasheet Section 2. Exceeding 5.5 V risks violating DC output voltage limits (VO ≤ VCC + 0.5 V) and may accelerate oxide degradation in the C2MOS process.

Can M74HCT541B1R drive a 50 Ω transmission line directly?

No - its output stage is designed for LSTTL fanout (10 loads), not 50 Ω termination. Driving such a line would require external series termination or a dedicated line driver. The specified 6 mA drive corresponds to VOH ≥ 4.18 V at 4.5 V VCC, not 50 Ω impedance matching.

Is the M74HCT541B1R pinout compatible with 74LS541 in DIP-20 packages?

Yes - pin assignments for G1/G2, A1–A8, Y1–Y8, VCC, and GND match exactly per JEDEC MS-001. However, note that M74HCT541B1R draws significantly less ICC (4 µA vs. ~20 mA) and has faster propagation (14 ns vs. ~23 ns), which may affect timing closure in legacy designs.

Does M74HCT541B1R support hot-swap or live-insertion?

No - it lacks bus-hold or power-up 3-state features. Applying VCC before G1/G2 control signals may cause output contention. For hot-swap applications, ST recommends adding external series resistors or using dedicated hot-swap buffers like the STUSB4750.