Diodes Incorporated PI74FCT573ATQ

Overview

PI74FCT573ATQ from Pericom Semiconductor is an 8-bit octal transparent latch with 3-state outputs, designed for bus-oriented digital systems where data isolation and controlled latching are required. It features TTL-compatible input/output levels, 5V supply operation, industrial temperature range (–40°C to +85°C), propagation delay as low as 3.8 ns (max), and low static power consumption (0.1 µA typical ICC). It is used in microprocessor data bus buffering and address/data separation in embedded control systems.

For engineers reviewing the PI74FCT573ATQ datasheet, PI74FCT573ATQ pinout, PI74FCT573ATQ application, or PI74FCT573ATQ equivalent, key selection considerations include latch enable polarity (active HIGH), output enable polarity (active LOW), 20-pin QSOP package compatibility, 3-state bus driving capability, and fast CMOS performance with TTL interface compatibility.

Technical Context

The PI74FCT573ATQ implements a transparent latch architecture: when LE is HIGH, inputs D0–D7 pass directly to outputs O0–O7; when LE transitions LOW, the input state is captured and held. OE controls output tristate - HIGH disables all outputs into high-impedance mode. This enables bidirectional bus sharing without contention.

It uses Fast CMOS technology with hysteresis on all inputs (200 mV), low ground bounce, and guaranteed logic thresholds (VIH = 2.0 V, VIL = 0.8 V) for noise immunity. The device supports 12 mA/64 mA output drive strength under VOL specifications and operates within 5.0 V ±5% supply tolerance.

Key Specifications

Pinout & Package

PI74FCT573ATQ is housed in a 20-pin QSOP (Quarter-Size Outline Package) with 0.635 mm pitch, 7.6 mm × 3.99 mm body size, and gull-wing leads suitable for automated SMT assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74F573SCX and SN74ACT573N, PI74FCT573ATQ uniquely combines QSOP packaging, 200 mV input hysteresis, and sub-4 ns propagation delay - making it optimal for space-constrained, noise-prone industrial bus interfaces where timing precision and layout efficiency are jointly critical.

Availability

PI74FCT573ATQ is available at Aetrix Electronics and suitable for industrial control panels, programmable logic controller (PLC) I/O modules, and embedded test instrumentation requiring stable component supply, long-term lifecycle support, and consistent QSOP packaging.

Supply support for PI74FCT573ATQ 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

Pericom Semiconductor was a fabless provider of high-performance interface, timing, and signal integrity solutions, acquired by Diodes Incorporated in 2016; its legacy logic portfolio remains widely deployed in industrial and communications infrastructure.

The PI74FCT573ATQ belongs to the FCT Fast CMOS logic family, engineered specifically for 5V bus-interface applications demanding low power, high noise immunity, and pin-for-pin compatibility with legacy bipolar logic - targeting industrial, telecom, and computing subsystems.

FAQ

What is the function of the LE and OE pins on PI74FCT573ATQ?

LE (Latch Enable) is active HIGH and controls data transparency: when HIGH, D0–D7 pass through to O0–O7; when it falls LOW, the current input state is latched. OE (Output Enable) is active LOW and controls output driver state: when LOW, outputs drive; when HIGH, all outputs enter high-impedance mode. These two controls allow independent management of data capture and bus release.

Does PI74FCT573ATQ support mixed-voltage operation?

No - PI74FCT573ATQ is strictly a 5V device with VCC specification of 5.0 V ±5%. Its input thresholds (VIH = 2.0 V, VIL = 0.8 V) and output drive characteristics are optimized for 5V TTL/CMOS systems. It does not support 3.3V or dual-supply operation, and applying voltages outside –0.5 V to +7.0 V risks permanent damage per absolute maximum ratings.

Can PI74FCT573ATQ replace PI74FCT373ATQ in a design?

No - they differ in pinout and functional behavior. PI74FCT373ATQ has complementary outputs (O0–O7 and O0̅–O7̅), while PI74FCT573ATQ provides only true outputs (O0–O7). Their pin configurations are incompatible: PI74FCT373ATQ places outputs on pins 2–9 and inputs on 13–20, whereas PI74FCT573ATQ places inputs on pins 2–9 and outputs on 13–20. PCB redesign is required for substitution.

What is the significance of hysteresis on PI74FCT573ATQ inputs?

The 200 mV input hysteresis provides noise immunity on LE and OE control lines by creating distinct threshold voltages for rising (≈1.0 V) and falling (≈0.8 V) edges. This prevents oscillation or false triggering due to slow signal edges, ground bounce, or EMI - especially important in industrial settings with relay coils, motor drives, or long cable runs feeding control signals.