STMicroelectronics M74HC540RM13TR

Overview

M74HC540RM13TR from STMicroelectronics is an octal inverting bus buffer with 3-state outputs, designed for bidirectional data bus interfacing in high-speed digital systems. It features 9 ns typical propagation delay at 6 V, ±6 mA output drive capability, and operates across 2–6 V supply range. Used in microcontroller peripheral expansion and memory address latching where signal inversion and bus isolation are required.

For engineers reviewing the M74HC540RM13TR datasheet, M74HC540RM13TR pinout, M74HC540RM13TR application, or M74HC540RM13TR equivalent, key selection criteria include verified 3-state enable timing (tPZL/tPLZ ≤ 28 ns at 6 V), symmetrical output impedance, wide temperature support (−55°C to +125°C), and TSSOP-20 package compatibility with high-density PCB layouts.

Technical Context

The M74HC540RM13TR implements dual active-high 3-state enable inputs (G1, G2) wired as a logical AND - both must be low for output drivers to be active; either high forces all eight Yn outputs into high-impedance state. Its C2MOS silicon process enables low static current (4 µA max at 25°C) while maintaining rail-to-rail input thresholds (VIH = 3.15 V min at VCC = 4.5 V).

Propagation delays tPLH and tPHL are balanced (≤2 ns skew at 6 V), and output transition times (tTLH/tTHL ≤15 ns at 6 V, CL = 50 pF) support clean edge integrity in 25 MHz bus environments. Input protection diodes and 28% VCC noise immunity ensure robust operation in electrically noisy industrial control backplanes.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, exposed pad not present, JEDEC MO-153 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC540N and 74VHC540FT, the M74HC540RM13TR uniquely combines TSSOP-20 footprint, dual-enable AND logic, guaranteed −55°C operation, and 4 µA quiescent current - making it optimal for space-constrained, wide-temperature, low-power industrial controllers.

Availability

M74HC540RM13TR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, automotive body control modules, medical infusion pump controllers, and test equipment digital pattern generators requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for M74HC540RM13TR 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 microcontrollers, power ICs, sensors, and analog components for industrial, automotive, and consumer markets.

The M74HC540 belongs to ST's high-speed CMOS logic family, engineered specifically for noise-immune, low-power bus interfacing in harsh-environment control systems where reliability across −55°C to +125°C is non-negotiable.

FAQ

What is the function of pins G1 and G2 on the M74HC540RM13TR?

Pins G1 and G2 are active-high 3-state enable inputs wired internally as an AND gate: only when both are logic low do the eight Y1–Y8 outputs actively drive inverted versions of A1–A8 inputs. If either G1 or G2 is high, all outputs enter high-impedance state - this dual-input design allows flexible bus arbitration and prevents contention in multi-master systems.

Can the M74HC540RM13TR operate reliably at 2.0 V supply?

Yes - the device is fully specified down to 2.0 V: VIH = 1.5 V (min), VOL = 0.1 V (max at 20 µA), and tPD = 40 ns (max) at CL = 50 pF. This enables direct interfacing with 2.0 V FPGA I/O banks or ultra-low-power microcontrollers without level translation, while maintaining 28% noise margin relative to VCC.

Is thermal pad connection required for the TSSOP-20 package?

No - the M74HC540RM13TR in TSSOP-20 (package code RM13TR) has no exposed thermal pad. The plastic body uses standard JEDEC MO-153 dimensions (6.5 mm × 4.4 mm), and thermal dissipation relies solely on PCB copper area under pins and standard 2-layer trace routing - no solder paste stencil or thermal via requirements apply.

How does the M74HC540RM13TR differ from the non-inverting M74HC541?

The M74HC540RM13TR provides inverted outputs (Yn = NOT An), whereas the M74HC541 delivers true outputs (Yn = An). Both share identical pinout, 3-state enable structure, and electrical specs, but the inversion enables direct replacement in designs requiring signal polarity reversal - such as correcting phase errors in differential bus terminations or matching legacy TTL logic conventions.