STMicroelectronics M74HC373B1R

Overview

M74HC373B1R from STMicroelectronics is a high-speed CMOS octal D-type transparent latch with 3-state non-inverting outputs, designed for bus-oriented data latching in digital systems. It operates from 2V to 6V, delivers 12ns typical propagation delay at 6V, supports ±6mA output drive, and features pin- and function-compatibility with standard 74-series 373 devices in DIP-20 package.

For engineers reviewing the M74HC373B1R datasheet, M74HC373B1R pinout, M74HC373B1R application, or M74HC373B1R equivalent, key selection criteria include latch enable timing (tW(H) = 6ns min at 6V), 3-state output disable time (tPHZ = 13ns max), input noise immunity (28% VCC min), and industrial temperature range (–55°C to +125°C).

Technical Context

The M74HC373B1R implements eight independent D-type latches controlled by a shared Latch Enable (LE) signal and a global Output Enable (OE) for 3-state bus control. Its sub-micron C2MOS process enables symmetrical output drive (|IOH| = IOL = 6mA min) and balanced tPLH/tPHL propagation delays.

It supports wide-voltage operation (2–6V), exhibits low quiescent current (ICC = 4µA max at 25°C), and integrates input protection against ESD and transient overvoltage. The device is not a registered driver or clocked flip-flop - it is a level-sensitive transparent latch with no internal clocking logic.

Key Specifications

Pinout & Package

Package: Plastic Dual In-line Package (DIP-20), 0.3" width, through-hole mounting. Pin pitch: 2.54 mm (0.1").

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal latch with 3-state output applications.

Compared with SN74HC373N and 74VHC373N, the M74HC373B1R offers the widest operating temperature range (–55°C to +125°C), lowest quiescent current (4µA), and full 2–6V compatibility - making it optimal for ruggedized embedded systems where reliability and power efficiency outweigh raw speed.

Availability

M74HC373B1R is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, legacy instrumentation interfaces, and embedded test equipment requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for M74HC373B1R 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 analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The M74HC373B1R belongs to ST's high-speed CMOS logic family, engineered specifically for robust bus interface applications requiring low power, wide voltage tolerance, and industrial-grade reliability.

FAQ

What is the maximum clock frequency supported by M74HC373B1R?

The M74HC373B1R is not a clocked device - it has no internal clock input. Its usable data rate depends on external LE timing: with 12ns typical tPD and 6ns minimum LE pulse width at 6V, it supports reliable bus toggling up to approximately 33 MHz in transparent mode and 25 MHz in latched strobe mode.

Can M74HC373B1R drive a 50Ω transmission line directly?

No. With 6mA output drive capability, the M74HC373B1R cannot source/sink sufficient current for 50Ω line termination. It is intended for stub-loaded buses or short PCB traces (<10 cm). For 50Ω lines, use a dedicated line driver or add series termination resistors (e.g., 33Ω) and ensure proper receiver termination.

Is M74HC373B1R RoHS compliant and lead-free?

Yes. M74HC373B1R is manufactured in STMicroelectronics' RoHS-compliant, lead-free DIP-20 package per EU Directive 2011/65/EU. The device carries the "E" suffix in marking per ST's packaging nomenclature and meets JEDEC J-STD-020 moisture sensitivity level MSL3.

How does the 3-state output behave when OE is floating?

OE must never be left floating. The input has no internal pull-up/down; an unconnected OE may float to an indeterminate voltage, causing partial turn-on of output transistors and excessive ICC or bus contention. Always tie OE to GND (enabled) or VCC (disabled) via a 10kΩ resistor if not actively driven.