Texas Instruments CY74FCT825CTQCT

Overview

CY74FCT825CTQCT from Texas Instruments is an 8-bit positive-edge-triggered bus-interface register with three independent output-enable controls (OE1/OE2/OE3), asynchronous clear (CLR), clock enable (EN), and 3-state outputs. It delivers 64 mA sink / 32 mA source drive, 6 ns propagation delay (tPLH/tPHL at CL = 50 pF), and operates across –40°C to +85°C on 4.75–5.25 V supply. It serves as a high-drive output port in address/data bus expansion and multi-master interface control.

For engineers reviewing the CY74FCT825CTQCT datasheet, CY74FCT825CTQCT pinout, CY74FCT825CTQCT application, or CY74FCT825CTQCT equivalent, key selection criteria include its triple-OE architecture for hierarchical bus arbitration, Ioff-enabled partial-power-down support, matched rise/fall times for EMI reduction, and FCT-family compatibility with TTL-level inputs/outputs.

Technical Context

This device implements eight D-type flip-flops synchronized to the low-to-high transition of CP, with EN gating data capture and CLR forcing Q outputs low asynchronously. Its output stage uses totem-pole drivers with edge-rate control circuitry to suppress ground bounce and crosstalk under heavy capacitive loads.

The triple OE structure (OE1, OE2, OE3) enables independent control of output groups-e.g., chip select, DMA request, and read/write strobes-allowing concurrent bus access management without external logic. Ioff functionality disables all outputs when VCC = 0 V, preventing backflow current during system power sequencing.

Key Specifications

Pinout & Package

Package: 24-pin SSOP (DBQ), 0.154" body width, 0.025" pitch, moisture sensitivity level 2 (260°C peak reflow, 1-year floor life).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit registered bus-interface applications.

Compared with CY74FCT244ATPVC and SN74ACT573NSR, the CY74FCT825CTQCT uniquely combines clocked registration, triple-OE arbitration, and asynchronous clear-making it irreplaceable in systems requiring deterministic timing, multi-domain bus control, and power-aware interface design.

Availability

CY74FCT825CTQCT is available at Aetrix Electronics and suitable for memory address latching, multi-master bus arbitration, and high-drive output port applications requiring stable component supply, long-term industrial lifecycle support, and RoHS-compliant packaging.

Supply support for CY74FCT825CTQCT 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

Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The CY74FCT825CTQCT belongs to TI's FCT logic family-designed specifically for high-speed, low-noise, TTL-compatible bus interfacing in industrial control, test equipment, and legacy system upgrades.

FAQ

What is the maximum clock frequency supported by CY74FCT825CTQCT?

The CY74FCT825CTQCT has a maximum propagation delay of 6 ns (CP→Y, CL = 50 pF), supporting reliable operation up to approximately 167 MHz in ideal conditions. Real-world frequency limits depend on board layout, load capacitance, and timing margins for setup/hold (tsu = 3 ns, th = 1.5 ns). For sustained 100+ MHz use, ensure controlled-impedance routing and minimize stub lengths.

Does CY74FCT825CTQCT support partial-power-down operation?

Yes, CY74FCT825CTQCT includes Ioff circuitry that actively disables outputs when VCC = 0 V, preventing damaging current backflow from live bus lines into unpowered sections. This feature is verified per JESD78 and enables safe power sequencing in modular systems-critical for applications like hot-pluggable I/O cards where subsystems power up/down independently.

How does the triple-OE architecture (OE1/OE2/OE3) function in CY74FCT825CTQCT?

In CY74FCT825CTQCT, OE1, OE2, and OE3 are OR'd internally: if any one is high, all Y0–Y7 outputs enter high-impedance state. This allows hierarchical bus control-for example, OE1 = chip select, OE2 = DMA grant, OE3 = read/write direction-enabling fine-grained arbitration without external logic. All three inputs share identical electrical specs (VIH = 2.0 V, VIL = 0.8 V) and timing behavior.

What is the purpose of the CLR pin in CY74FCT825CTQCT, and how does it interact with EN and CP?

The CLR pin in CY74FCT825CTQCT is an asynchronous active-low reset that forces all Y outputs low immediately, overriding both EN and CP states. When CLR = L, outputs remain low regardless of clock edges or enable status. When CLR = H, normal register operation resumes-data transfers occur on CP↑ only if EN = L. This provides deterministic initialization independent of clock timing.

Is CY74FCT825CTQCT pin-compatible with other members of the CY74FCT825x family?

Yes, CY74FCT825CTQCT shares identical pinout and function mapping with CY74FCT825ATSOC (SOIC-24) and CY74FCT825BTQCT (faster speed grade), including D0–D7, Y0–Y7, CP, CLR, EN, OE1–OE3, VCC, and GND. All variants use the same logic diagram and timing model-only propagation delay and drive strength differ across speed grades (A/B/C), making them drop-in replacements where timing裕度 permits.