STMicroelectronics 74VHCT574ATTR

Overview

74VHCT574ATTR from STMicroelectronics is an octal D-type flip-flop with non-inverting 3-state outputs, designed for high-speed synchronous data latching in 5V digital systems. It features 180 MHz typical maximum clock frequency, 4 µA max quiescent current at 25°C, and TTL-compatible input thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V), enabling direct interfacing with legacy 74-series logic in industrial control and bus interface applications.

For engineers reviewing the 74VHCT574ATTR datasheet, 74VHCT574ATTR pinout, 74VHCT574ATTR application, or 74VHCT574ATTR equivalent, key selection criteria include propagation delay matching (tPLH/tPHL ≤ 10.5 ns), output drive capability (IOH/IOL ≥ 8 mA), 3-state enable timing (tPZL/tPLZ ≤ 11.5 ns), and operation across –40°C to +85°C industrial temperature range.

Technical Context

This device implements edge-triggered synchronous storage using a positive-going clock transition to capture D-input states into eight independent D-type latches. Its 3-state output control is independent of internal latch operation, allowing data retention or update while outputs are disabled.

Designed for 5V operation (4.5–5.5 V), it integrates power-down protection on all I/O pins-accepting input voltages from 0 to 7 V regardless of supply-and provides 2 kV ESD immunity via on-chip protection diodes. Output impedance is symmetrical (|IOH| = |IOL| ≥ 8 mA), and propagation delays are balanced (tPLH ≅ tPHL).

Key Specifications

Pinout & Package

74VHCT574ATTR is housed in a 20-pin TSSOP (Thin Shrink Small Outline Package) with 0.65 mm pitch, measuring 6.5 × 6.4 mm and optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal D-type flip-flop applications.

Compared with 74HC574PW and SN74LV574APWR, the 74VHCT574ATTR uniquely combines 5V TTL compatibility, 140 MHz operation, and 0–7 V input tolerance-making it the only choice for robust, high-speed 5V industrial bus latching without external protection circuitry.

Availability

74VHCT574ATTR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, memory address latching, and legacy bus interface adapter applications requiring stable component supply, long-term lifecycle support, and guaranteed 5V logic compatibility.

Supply support for 74VHCT574ATTR 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, and consumer markets since 1987.

The VHCT logic family targets high-speed, low-power 5V CMOS applications with TTL-compatible interfaces-specifically engineered for seamless migration from bipolar 74-series logic in industrial control and instrumentation systems.

FAQ

What is the maximum clock frequency supported by the 74VHCT574ATTR?

The 74VHCT574ATTR supports a maximum clock frequency of 140 MHz over the full industrial temperature range (–40°C to +85°C), with a typical value of 180 MHz at 25°C and VCC = 5.0 V. This rating is verified under CL = 50 pF load conditions and ensures reliable operation in high-speed synchronous data capture applications such as bus latching and address registration.

Does the 74VHCT574ATTR support mixed-voltage interfacing?

Yes-the 74VHCT574ATTR provides true mixed-voltage robustness: its inputs accept 0–7 V regardless of VCC, enabling safe interfacing between 5V logic and 3.3V or 2.5V systems without level shifters. This is achieved via integrated power-down protection circuits, not just voltage translation, making it suitable for hot-swap and partial-power-down scenarios in industrial backplanes.

How does the 3-state output control behave relative to internal latch operation?

The OE (output enable) signal operates independently of the internal flip-flop state. When OE is HIGH, all Q outputs enter high-impedance mode without affecting stored data-allowing new D-input values to be captured on subsequent clock edges or retained indefinitely. This decoupling enables dynamic bus sharing and glitch-free state transitions in multi-master systems.

What is the significance of VOLP ≤ 1.6 V in practical design?

VOLP (dynamic low-voltage quiet output) quantifies ground bounce during simultaneous switching. At ≤1.6 V, the 74VHCT574ATTR limits noise-induced false triggering in adjacent logic, especially critical in dense 8-bit parallel interfaces like memory address buses or PLC I/O modules. This specification is measured with worst-case package conditions and 50 pF load, directly supporting robust timing margin analysis.