Diodes Incorporated PI74FCT541TQE

Overview

PI74FCT541TQE from Pericom Semiconductor is a fast CMOS non-inverting octal buffer/line driver with 3-state outputs, designed for high-speed bus driving in memory, address, and clock distribution systems. It features TTL-compatible input/output levels, 25Ω series output resistors to suppress reflections, low ground bounce, and operates across –40°C to +85°C.

For engineers reviewing the PI74FCT541TQE datasheet, PI74FCT541TQE pinout, PI74FCT541TQE application, or PI74FCT541TQE equivalent, key selection criteria include propagation delay (≤6.0 ns), output drive strength (64 mA sink), 3-state enable logic polarity, QSOP-20 package compatibility, and industrial temperature support.

Technical Context

The PI74FCT541TQE implements dual active-low 3-state output enables (OEA, OEB) controlling separate groups of four outputs each, enabling flexible bus partitioning. Its non-inverting architecture preserves signal polarity while delivering rail-to-rail CMOS output swing at 5 V supply.

All eight outputs integrate 25Ω series termination resistors-eliminating external resistors and reducing PCB trace reflection noise. Input hysteresis (200 mV) ensures robust noise immunity on slow-rising signals, critical in noisy industrial bus environments.

Key Specifications

Pinout & Package

PI74FCT541TQE is housed in a Pb-free, green 20-pin QSOP (150-mil width) package with 0.65 mm lead pitch and gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal non-inverting buffer applications.

Compared with SN74F244N and 74LCX244MTCX, PI74FCT541TQE uniquely combines 5 V TTL compatibility, integrated 25Ω termination, input hysteresis, and industrial temperature range-making it optimal for upgrading legacy bus drivers in harsh environments without redesigning termination networks.

Availability

PI74FCT541TQE is available at Aetrix Electronics and suitable for memory address buffering, system clock distribution, backplane data interfacing, and industrial PLC I/O conditioning requiring stable component supply and long-term manufacturability.

Supply support for PI74FCT541TQE 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, timing, and signal integrity solutions, acquired by Diodes Incorporated in 2016. Its FCT logic family targeted performance upgrades over legacy bipolar logic.

The PI74FCT541TQE belongs to the FCT (Fast CMOS Technology) logic product line, engineered to replace 74F-series bipolar buffers with superior speed, lower power, and enhanced noise immunity for industrial and computing bus applications.

FAQ

What is the function of pins 1 and 19 (OEA and OEB) on the PI74FCT541TQE?

Pins 1 (OEA) and 19 (OEB) are independent active-low 3-state output enable inputs. OEA controls outputs Y0–Y3; OEB controls Y4–Y7. When either is HIGH, its associated four outputs enter high-impedance state. Both must be LOW for full 8-bit output drive. This allows segmented bus control without external logic.

Does the PI74FCT541TQE require external pull-up or pull-down resistors on its control inputs?

No. The PI74FCT541TQE has no internal weak pull-ups or pull-downs on OEA/OEB. However, due to its TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), unused enable inputs must be actively driven LOW (to GND) or HIGH (to VCC) - floating inputs risk indeterminate output states and increased ICC. A 10 kΩ pull-down is acceptable if driven by open-collector sources.

Can the PI74FCT541TQE drive a 50 Ω transmission line directly?

No. Its integrated 25Ω series resistor is optimized for unterminated 75–100 Ω PCB traces driving TTL loads, not 50 Ω coaxial or controlled-impedance lines. For true 50 Ω source termination, an external 25Ω resistor in series with the output is required - but this would double total series resistance to 50Ω, degrading edge rate. Use dedicated 50 Ω line drivers (e.g., PI6C1080x) for RF or high-speed serial links.

Is the PI74FCT541TQE pin-compatible with the PI74FCT244TQE?

No. PI74FCT541TQE uses a functionally grouped pinout: inputs D0–D7 on one side (pins 2–9), outputs Y0–Y7 on the opposite side (pins 11–18), with OEA/OEB on corners. PI74FCT244TQE uses interleaved I/O (D0/Y0/D1/Y1…). Layouts are not interchangeable; routing and footprint must be redesigned to accommodate the physical separation of inputs and outputs.