STMicroelectronics M74HCT245RM13TR

Overview

M74HCT245RM13TR from STMicroelectronics is an octal non-inverting bus transceiver with 3-state outputs, designed for bidirectional asynchronous data bus interfacing. It features directional control (DIR), output enable (G), symmetrical drive strength (±6 mA), 13 ns typical propagation delay at 4.5 V, and TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V). Used in industrial backplane interconnects and microcontroller peripheral expansion.

For engineers reviewing the M74HCT245RM13TR datasheet, M74HCT245RM13TR pinout, M74HCT245RM13TR application, or M74HCT245RM13TR equivalent, key selection criteria include 3-state isolation timing (tPZL/tPLZ ≤ 45 ns), supply current under quiescent conditions (ICC ≤ 4 µA), operating temperature range (–55°C to +125°C), and TSSOP-20 package compatibility with high-density PCB layouts.

Technical Context

This device implements a dual-bus bidirectional interface using CMOS silicon gate C2MOS technology. Direction of data flow (A→B or B→A) is controlled by the DIR input, while G enables or disables all outputs into high-impedance state. Input protection circuits guard against ESD and transient overvoltage.

Propagation delays are balanced (tPLH ≅ tPHL), and output impedance is symmetrical (|IOH| = IOL ≥ 6 mA). It operates within 4.5–5.5 V supply range and supports input rise/fall times up to 500 ns without degradation.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, 1.2 mm height, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT245PW and 74VHC245FT, M74HCT245RM13TR delivers the widest temperature range (–55°C to +125°C), lowest propagation delay variation across temperature, and highest guaranteed output drive - making it optimal for harsh-environment real-time control systems.

Availability

M74HCT245RM13TR is available at Aetrix Electronics and suitable for industrial backplane interfacing, microcontroller peripheral expansion, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for M74HCT245RM13TR 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, specializing in automotive, industrial, and power management ICs with vertical manufacturing capabilities.

M74HCT245RM13TR belongs to the HCT logic family - engineered for TTL-compatible CMOS performance in noise-immune, high-reliability industrial control and instrumentation systems.

FAQ

What is the maximum clock frequency supported by M74HCT245RM13TR in a synchronous bus application?

The device does not operate on a clock; it is asynchronous. However, its 13 ns typical propagation delay and ≤45 ns 3-state disable time support reliable data handshaking up to 30 MHz in systems with matched trace lengths and proper termination. Maximum usable frequency depends on system-level timing margins, including setup/hold times of connected devices and PCB trace delays.

Can M74HCT245RM13TR be used with 3.3 V logic interfaces?

No - its input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and recommended VCC range (4.5–5.5 V) are specified for 5 V operation only. Driving it from 3.3 V sources risks marginal VIH compliance, and powering it at 3.3 V violates absolute maximum ratings. Use a dedicated 3.3 V–5 V level translator like TXB0108 for mixed-voltage interconnects.

Is the TSSOP-20 package of M74HCT245RM13TR compatible with reflow soldering per J-STD-020?

Yes - the M74HCT245RM13TR TSSOP-20 package is rated for standard Pb-free reflow profiles (peak temperature 260°C, 20–40 sec above 217°C). Its moisture sensitivity level (MSL) is 1, meaning unlimited floor life at ≤30°C/60% RH, eliminating bake requirements prior to assembly.

Does M74HCT245RM13TR require external pull-up or pull-down resistors on DIR or G pins?

No - DIR and G have CMOS-compatible input structure with negligible leakage (<1 µA). However, floating inputs must be avoided: unconnected DIR or G pins will cause undefined direction or unintended output enable states. External biasing (e.g., 10 kΩ to VCC or GND) is required only if the driving source is open-drain or may float during power-up/reset.