STMicroelectronics 74ACT573TTR

Overview

74ACT573TTR from STMicroelectronics is an advanced high-speed CMOS octal D-type latch with non-inverting 3-state outputs, designed for bus interface and data latching in TTL/CMOS mixed-signal systems. It features 5 ns typical propagation delay at 5 V, ±24 mA symmetrical output drive, 4.5–5.5 V operating range, and 2 kV ESD immunity.

For engineers reviewing the 74ACT573TTR datasheet, 74ACT573TTR pinout, 74ACT573TTR application, or 74ACT573TTR equivalent, key selection criteria include latch enable timing (1 ns min pulse width), output disable time (6.5 ns typ), 50 Ω transmission line driving capability, and TSSOP-20 package compatibility with space-constrained PCB layouts.

Technical Context

The 74ACT573TTR implements dual-control latching via independent LE (latch enable) and OE (output enable) inputs, enabling precise data capture and bus isolation. Its C2MOS sub-micron process ensures low quiescent current (4 µA max) while maintaining TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) across temperature.

Propagation delays are balanced (tPLH ≅ tPHL), and output impedance is symmetrical (|IOH| = IOL = 24 mA min), supporting clean signal integrity on terminated 50 Ω lines. The device operates over –55°C to +125°C with guaranteed AC performance at CL = 50 pF and RL = 500 Ω.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, lead-free, moisture sensitivity level 1 (MSL1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT573PW and 74LCX573MTCX, the 74ACT573TTR uniquely combines 5 V operation, 5 ns speed, and explicit 50 Ω line drive validation-making it optimal for legacy 5 V industrial bus interfaces requiring minimal redesign.

Availability

74ACT573TTR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, and medical imaging backplanes requiring stable component supply and long-term lifecycle support.

Supply support for 74ACT573TTR 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 discrete components for industrial, automotive, and consumer markets.

The 74ACT573 belongs to ST's legacy high-speed CMOS logic family, engineered specifically for robust 5 V bus interfacing in mixed-technology systems where TTL compatibility, ESD resilience, and precise timing control are critical.

FAQ

What is the maximum clock frequency supported by the 74ACT573TTR?

The 74ACT573TTR does not operate on a clock signal-it is edge-triggered by the LE input. Its usable data rate depends on setup/hold times (ts = 3.0 ns max, th = 3.0 ns max) and propagation delay (tPD = 5 ns typ). In practice, it supports reliable latching up to ~80 MHz with proper PCB layout and termination.

Can the 74ACT573TTR drive a 50 Ω transmission line directly?

Yes-the datasheet explicitly specifies "50 Ω transmission line driving capability" and confirms symmetrical 24 mA output drive (IOL/IOH min) at VCC = 5 V. This allows direct connection to properly terminated 50 Ω traces without external series resistors or buffers in point-to-point configurations.

Is the 74ACT573TTR pin-compatible with standard 74LS573 devices?

Yes-pin and function compatibility with the 74 series 573 is explicitly stated in the datasheet. Pinout matches exactly (D0–D7, Q0–Q7, LE, OE, VCC, GND), and logic behavior (non-inverting 3-state latch) is identical. However, voltage thresholds and speed differ: ACT versions require tighter VIH/VIL margins and deliver 5 ns vs. 17 ns typical delay.

Does the 74ACT573TTR support hot insertion or live bus swapping?

No-while it features 2 kV HBM ESD protection and high-impedance outputs, the device lacks bus-hold or powered-off protection circuitry. Applying signals to inputs or outputs while VCC is unpowered may cause latch-up or damage due to input diode conduction. Power sequencing must ensure VCC is stable before asserting LE or OE.