Diodes Incorporated PI74FCT245DTQE

Overview

PI74FCT245DTQE from Pericom Semiconductor is an octal bidirectional transceiver IC designed for asynchronous two-way data bus communication between A- and B-side 8-bit parallel buses. It features TTL-compatible input/output levels, 3.8 ns max propagation delay (tPLH/tPHL), 5.0 ns max output enable/disable timing, and operates at 5.0 V ±5% over –40°C to +85°C. Used in industrial backplane interconnects where direction control and bus isolation are required.

For engineers reviewing the PI74FCT245DTQE datasheet, PI74FCT245DTQE pinout, PI74FCT245DTQE application, or PI74FCT245DTQE equivalent, key selection criteria include bidirectional flow control via T/R and OE pins, low ground bounce outputs, 20-pin QSOP package compatibility, and guaranteed 2.4 V VOH at –15 mA drive.

Technical Context

This device implements dual 8-bit bidirectional I/O ports with independent transmit/receive (T/R) logic and active-low 3-state output enable (OE). Direction is determined solely by T/R state: HIGH enables A→B flow; LOW enables B→A flow. OE HIGH forces both sides into high-impedance state regardless of T/R.

It uses Fast CMOS technology with hysteresis on all inputs (200 mV), supports 120 mA DC output current per pin, and delivers 0.1–500 µA quiescent supply current. No internal series termination - unlike PI74FCT2245DTQE - making it suitable for systems using external impedance matching.

Key Specifications

Pinout & Package

PI74FCT245DTQE is housed in a 20-pin QSOP (Quarter Size Outline Package) with 0.635 mm pitch, 3.99 mm body width, and gull-wing leads. Pin 1 is marked by a beveled corner; pin numbering follows standard counter-clockwise layout starting from top-left.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74F245N and 74LCX245MTCX, PI74FCT245DTQE offers superior speed-power tradeoff at 5 V, industrial temperature support, and noise-hardened inputs - making it optimal for new 5 V industrial bus designs where reliability and timing margin are critical.

Availability

PI74FCT245DTQE is available at Aetrix Electronics and suitable for industrial backplane interconnects, microcontroller bus expansion, legacy system emulation, and automated test equipment requiring stable component supply and long-term manufacturability.

Supply support for PI74FCT245DTQE 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, acquired by Diodes Incorporated in 2016; its legacy timing and logic portfolio remains widely deployed in industrial and communications infrastructure.

PI74FCT245DTQE belongs to the FCT Fast CMOS logic family, engineered for 5 V systems demanding TTL compatibility, low power, and robust noise immunity - specifically targeting bus bridging in programmable logic, instrumentation, and control applications.

FAQ

What is the function of the T/R pin on PI74FCT245DTQE?

The T/R (Transmit/Receive) pin is a direction-control input that determines data flow direction: when HIGH, data passes from Side-A (A0–A7) to Side-B (B0–B7); when LOW, data flows from Side-B to Side-A. It operates independently of OE and must be stable before OE is deasserted to prevent bus contention. Its hysteresis (200 mV) rejects noise on control lines.

Does PI74FCT245DTQE include internal series termination resistors?

No. PI74FCT245DTQE does not integrate 25 Ω series output resistors - that feature is exclusive to the PI74FCT2245DTQE variant. This makes PI74FCT245DTQE appropriate for systems using external termination or controlled-impedance PCB routing, whereas PI74FCT2245DTQE targets reflection-sensitive stub-based topologies.

Can PI74FCT245DTQE operate at 3.3 V supply?

No. PI74FCT245DTQE is specified only for 5.0 V ±5% operation (4.75–5.25 V). Applying 3.3 V will result in undefined logic thresholds, degraded noise margins, and failure to meet VOH/VOL specifications. For 3.3 V systems, consider 74LCX245 or 74ALVC245 families instead.

What is the maximum capacitive load supported per output?

Each output is characterized for CL = 50 pF in switching tests, and the datasheet specifies tPLH/tPHL up to that load. While not explicitly rated beyond 50 pF, practical use with ≤70 pF (including trace + receiver input) is feasible if timing margins are verified; exceeding this may increase propagation delay nonlinearly and risk setup/hold violations in synchronous systems.