STMicroelectronics M74HC373TTR

Overview

M74HC373TTR from STMicroelectronics is a high-speed CMOS octal D-type transparent latch with 3-state non-inverting outputs, operating from 2V to 6V supply, delivering 12ns typical propagation delay at 6V, ±6mA output drive, and 4µA max quiescent current at 25°C - used for bidirectional bus buffering and data latching in industrial control and instrumentation systems.

For engineers reviewing the M74HC373TTR datasheet, M74HC373TTR pinout, M74HC373TTR application, or M74HC373TTR equivalent, key selection criteria include latch enable timing (min 6ns LE pulse width at 6V), 3-state output disable/enable times (13–15ns), input noise immunity (28% VCC), symmetrical drive capability, and TSSOP-20 package compatibility with board space-constrained digital logic interfaces.

Technical Context

The M74HC373TTR implements eight independent D-type latches controlled by a shared Latch Enable (LE) signal; when LE is HIGH, Q outputs follow D inputs transparently; when LE transitions LOW, outputs freeze the concurrent D values. Its 3-state outputs are managed separately via an active-low Output Enable (OE) pin, enabling bus-sharing without external gating.

Designed using sub-micron silicon gate C2MOS technology, it achieves balanced tPLH ≅ tPHL propagation delays, symmetrical |IOH| = |IOL| ≥ 6mA drive strength, and high noise immunity (VIH/VIL thresholds fixed at 70%/30% of VCC across 2–6V), ensuring robust operation in mixed-voltage logic environments.

Key Specifications

Pinout & Package

TSSOP-20 package: 4.4mm × 6.5mm body, 0.65mm pitch, 1.2mm max height, lead-free, RoHS-compliant surface-mount outline optimized for automated assembly and thermal performance in dense PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC373PW and 74VHC373FT, the M74HC373TTR delivers optimal balance of noise immunity, industrial temperature support, and proven reliability in long-lifecycle embedded systems - especially where ESD robustness and consistent 28% VCC threshold stability are prioritized over marginal speed gains.

Availability

M74HC373TTR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, automotive body control modules, and medical patient monitor data acquisition requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for M74HC373TTR 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 microcontrollers, power ICs, sensors, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

The M74HC373TTR belongs to ST's high-speed HC logic family, engineered for pin-compatible migration from legacy TTL and low-power operation in space-constrained, noise-prone embedded control applications.

FAQ

What is the minimum LE pulse width required for reliable latching at 3.3V supply?

At VCC = 3.3V, the minimum LE pulse width is 19ns (max) across -40°C to 85°C per AC specifications. This ensures setup/hold margins for internal node charging; design margin recommends ≥25ns for robust operation with PCB trace skew and temperature variation.

Can M74HC373TTR drive a 50Ω transmission line directly?

No - its 6mA output drive is rated for capacitive loads up to 50pF, not 50Ω DC termination. Driving 50Ω lines requires external series resistors (typically 33Ω) or dedicated line drivers; direct connection causes excessive current (100mA at 5V) and violates absolute max ratings.

Is the TSSOP-20 package thermally enhanced compared to SO-20?

Yes - the TSSOP-20 (M74HC373TTR) has lower thermal resistance (θJA ≈ 145°C/W vs. SO-20's ~160°C/W) due to thinner mold compound and shorter internal bond wires, enabling sustained 6mA output drive at 85°C ambient without derating.

Does the device support hot insertion or live bus swapping?

No - the M74HC373TTR lacks hot-swap protection circuitry. Applying VCC while OE or LE are asserted may cause bus contention or latch-up. Power sequencing must ensure VCC stabilizes before enabling control inputs, per ST's AN2057 guidelines.