Diodes Incorporated PI74FCT2245ATQE

Overview

PI74FCT2245ATQE from Pericom Semiconductor is a fast CMOS octal bidirectional transceiver with 25-Ω series output termination, TTL-compatible I/O, and industrial temperature range (–40°C to +85°C). It features 8-bit A/B data paths, active-low 3-state output enable (OE), and transmit/receive (T/R) direction control. Used in asynchronous bus interfacing between microcontrollers and peripheral subsystems requiring noise-suppressed signal integrity.

For engineers reviewing the PI74FCT2245ATQE datasheet, PI74FCT2245ATQE pinout, PI74FCT2245ATQE application, or PI74FCT2245ATQE equivalent, key selection criteria include bidirectional bus isolation timing (tPLH/tPHL ≤ 4.6 ns), integrated 25-Ω series termination, low ground bounce, and compatibility with legacy FAST™-series PCB footprints.

Technical Context

This device implements an octal, dual-bus bidirectional transceiver architecture where data flow direction is controlled by the T/R input: HIGH enables A→B transfer, LOW enables B→A transfer. OE (active LOW) independently places both A and B ports into high-impedance state regardless of T/R state.

All I/O pins support TTL voltage levels (VIH = 2.0 V, VIL = 0.8 V), exhibit 200 mV input hysteresis for noise immunity, and feature low static ICC (≤ 500 µA) and dynamic power consumption scaling with toggle rate (ICCD = 0.15–0.25 mA/MHz).

Key Specifications

Pinout & Package

PI74FCT2245ATQE is packaged in a 20-pin plastic TSSOP (Thin Shrink Small Outline Package), 173-mil wide (4.4 mm body width), with 0.65 mm lead pitch and gull-wing terminations.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74F2245N and 74LVC245APW, PI74FCT2245ATQE uniquely delivers 5 V TTL compatibility, built-in termination, and industrial temperature support in a drop-in FAST™-compatible package-making it optimal for legacy system upgrades demanding signal integrity and reliability.

Availability

PI74FCT2245ATQE is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, and legacy microcontroller bus expansion requiring stable component supply and long-term lifecycle assurance.

Supply support for PI74FCT2245ATQE 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-speed interface and signal integrity solutions, later acquired by Diodes Incorporated in 2016; its FCT logic portfolio remains widely deployed in industrial and communications infrastructure.

The PI74FCT2245 series targets noise-sensitive 5 V bus bridging applications where signal fidelity, low power, and drop-in upgradeability from bipolar FAST™ logic are critical design requirements.

FAQ

What is the function of the T/R pin on PI74FCT2245ATQE?

The T/R (Transmit/Receive) pin controls data direction: when HIGH, data flows from Side A (pins A0–A7) to Side B (B0–B7); when LOW, data flows from Side B to Side A. This enables single-wire direction arbitration without external logic, supporting half-duplex bus protocols in real-time control systems.

Does PI74FCT2245ATQE require external termination resistors?

No. PI74FCT2245ATQE integrates a 25 Ω series resistor on every output pin (A0–A7 and B0–B7), matching standard PCB trace impedances and eliminating reflections. This removes the need for 25 Ω discrete resistors typically placed near connectors or stubs in high-speed bus designs.

Can PI74FCT2245ATQE operate with a 3.3 V supply?

No. PI74FCT2245ATQE is specified only for VCC = 5.0 V ±5% (4.75 V to 5.25 V). Its TTL-compatible inputs require VIH ≥ 2.0 V and VIL ≤ 0.8 V, and internal logic thresholds are calibrated for 5 V operation. Using 3.3 V will result in undefined logic states and failure to meet AC timing specs.

How does the OE pin interact with the T/R control logic?

OE (Output Enable, active LOW) overrides T/R: when OE = HIGH, both A and B ports enter high-impedance state regardless of T/R value. When OE = LOW, T/R determines direction. This allows independent bus release (OE) and directional control (T/R), essential for multi-master arbitration and hot-swap-safe bus designs.