STMicroelectronics M74HCT573TTR

Overview

M74HCT573TTR from STMicroelectronics is a high-speed CMOS octal D-type latch with 3-state non-inverting outputs, designed for bus-oriented data latching in TTL- and HCMOS-compatible systems. It features 21 ns typical propagation delay (LE→Q), 6 mA minimum output drive, 4 µA maximum quiescent current at 25°C, and operates across 4.5–5.5 V supply. Used in microcontroller address/data bus isolation and memory interface control.

For engineers reviewing the M74HCT573TTR datasheet, M74HCT573TTR pinout, M74HCT573TTR application, or M74HCT573TTR equivalent, key selection criteria include 3-state output timing (tPZL/tPHZ ≤ 38 ns), latch enable setup/hold requirements (ts = 4 ns min, th = 5 ns min), and TSSOP-20 thermal performance under industrial temperature range (−55°C to +125°C).

Technical Context

The M74HCT573TTR implements an edge-triggered latch function controlled by a level-sensitive LE input: Q outputs follow D inputs while LE is HIGH, and hold the last D value when LE transitions LOW. Its 3-state OE control enables bidirectional bus sharing without external logic.

All eight D-to-Q paths operate independently with matched tPLH ≈ tPHL propagation delays and symmetrical |IOH| = IOL ≥ 6 mA output impedance-critical for minimizing bus contention skew and signal integrity degradation in multiplexed data paths.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, 0.75 mm max height, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT573PW and 74VHC573FT, the M74HCT573TTR uniquely combines full −55°C to +125°C qualification, 4 µA ultra-low ICC, and STMicroelectronics' long-term industrial product continuity-making it optimal for mission-critical embedded deployments where lifecycle stability and environmental robustness are mandatory.

Availability

M74HCT573TTR is available at Aetrix Electronics and suitable for microcontroller bus isolation, memory address latching, and industrial I/O expansion requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for M74HCT573TTR 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, delivering silicon solutions for automotive, industrial, power, and embedded applications since 1987.

The M74HCT573 belongs to ST's high-speed CMOS logic family, engineered specifically for seamless interoperability between TTL, NMOS, and modern CMOS systems while maintaining industrial-grade reliability and longevity.

FAQ

What is the maximum clock frequency supported by the M74HCT573TTR?

The M74HCT573TTR does not operate on a clock signal-it is a level-sensitive latch controlled by LE and OE inputs. Its usable data rate depends on propagation delays and setup/hold timing: with tPLH = 21 ns typ. and ts = 4 ns min., it supports reliable operation up to approximately 20 MHz in synchronous bus systems when driven by a clean LE strobe.

Can the M74HCT573TTR be used with a 3.3 V microcontroller?

No-the M74HCT573TTR requires VCC = 4.5–5.5 V and has TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V). While 3.3 V logic may meet VIH, it risks violating VIL margin and is outside recommended operating conditions. Use 74LVC573 or level-shifting buffers for 3.3 V systems.

Is the M74HCT573TTR pin-compatible with the 74LS573 in TSSOP-20?

Yes-M74HCT573TTR uses the same TSSOP-20 pinout and logic function as the 74LS573, including identical OE, LE, D0–D7, and Q0–Q7 assignments. However, it draws significantly less supply current and offers improved noise immunity and temperature range.

Does the M74HCT573TTR require external pull-up resistors on its outputs?

No-its 3-state outputs have active push-pull drivers capable of sourcing/sinking ≥6 mA. Pull-ups are unnecessary unless interfacing with open-drain buses or implementing wired-AND logic, which is not the intended use case for this latch.