Diodes Incorporated PI74FCT273ATQ

Overview

PI74FCT273ATQ from Pericom Semiconductor is an octal D-type flip-flop with master reset, designed for synchronous data latching in high-speed digital systems. It features edge-triggered operation on the rising clock edge, 25Ω series output resistors to suppress signal reflections, TTL-compatible I/O levels (VIH = 2.0 V, VOL = 0.50 V at 12 mA), and operates across –40°C to +85°C. Used in address/data register stages of industrial microcontroller buses.

For engineers reviewing the PI74FCT273ATQ datasheet, PI74FCT273ATQ pinout, PI74FCT273ATQ application, or PI74FCT273ATQ equivalent, key selection criteria include propagation delay (tPLH/tPHL ≤ 4.4 ns at 5V), setup/hold timing (tSU = 2.0 ns, tH = 1.5 ns), output drive capability (IOL = 12 mA with 25Ω series termination), and industrial temperature compliance.

Technical Context

This device implements eight independent D flip-flops sharing a common rising-edge-triggered clock (CP) and active-low asynchronous master reset (MR). All outputs respond synchronously to CP transitions, with data sampled one setup time before the LOW-to-HIGH clock edge and transferred to O0–O7.

The integrated 25Ω series resistor on each output eliminates external termination while maintaining signal integrity on PCB traces up to 10 inches. Input hysteresis (200 mV) improves noise immunity, and low ground bounce supports dense logic layouts without compromising timing margins.

Key Specifications

Pinout & Package

PI74FCT273ATQ is housed in a 20-pin 150 mil wide plastic TQSOP (Thin Quad Small Outline Package), pin-compatible with industry-standard SOIC-20 footprints but with 0.65 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74FCT273ATPWR and 74ACT273SCX, PI74FCT273ATQ delivers identical timing and drive strength with integrated termination-reducing BOM count by eight resistors and eliminating associated layout area and routing complexity.

Availability

PI74FCT273ATQ is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy bus interface registers, and motor control feedback capture requiring stable component supply and long-term lifecycle support.

Supply support for PI74FCT273ATQ 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 Corporation, headquartered in San Jose, CA, specialized in high-speed interface and timing solutions before its acquisition by Diodes Incorporated in 2016.

The PI74FCT series was engineered for 5V TTL-compatible logic replacement in industrial and communications equipment, emphasizing speed, noise immunity, and reduced external component count.

FAQ

Is PI74FCT273ATQ compatible with 3.3V logic systems?

No. PI74FCT273ATQ is specified for 5.0 V ±5% operation only. Its VIH (2.0 V) and VIL (0.8 V) thresholds, along with 25Ω output resistors optimized for 5V signaling, make it unsuitable for direct interfacing with 3.3V-only systems without level translation. Attempting 3.3V VCC operation violates absolute maximum ratings and risks functional failure.

Does the 25Ω series resistor affect fan-out capability?

Yes - the integrated 25Ω resistor limits peak output current but enhances signal integrity. At 12 mA drive (VOL ≤ 0.50 V), it supports fan-out to one standard TTL load or two CMOS loads on short traces. For higher fan-out, external buffers are recommended rather than removing termination, which would degrade edge fidelity.

Can MR be left unconnected in normal operation?

No. MR is active-low and internally undriven; leaving it floating risks unintended resets due to noise coupling. It must be pulled HIGH via a 10 kΩ resistor to VCC or driven actively. The datasheet specifies MR must be held HIGH during normal clocked operation to prevent asynchronous clearing of all outputs.

What is the maximum clock frequency supported by PI74FCT273ATQ?

While not explicitly rated as a maximum frequency, the 4.4 ns propagation delay and 2.0 ns setup time establish a practical limit of ~227 MHz for single-stage register operation under ideal conditions. Real-world designs targeting >50 MHz should verify timing margins using worst-case VCC, temperature, and capacitive loading per the switching characteristics table.