Texas Instruments CY74FCT2244CTQC

Overview

CY74FCT2244CTQC from Texas Instruments is an octal 3-state buffer/line driver with integrated 25-Ω output series resistors, TTL-compatible I/O levels, and I_off support for partial-power-down operation. It delivers 12 mA sink / 15 mA source drive, 4.1 ns max propagation delay (t_PLH/t_PHL), and operates across –40°C to +85°C. It is used in memory address driving, clock distribution, and bus transceiver applications requiring noise-suppressed signal integrity.

For engineers reviewing the CY74FCT2244CTQC datasheet, CY74FCT2244CTQC pinout, CY74FCT2244CTQC application, or CY74FCT2244CTQC equivalent, key selection criteria include its 25-Ω on-die termination, dual 3-state enable control (OEA/OEB), I_off protection, and QSOP-20 package compatibility with legacy FCT logic families.

Technical Context

This device implements two independent 4-bit noninverting buffers, each controlled by a dedicated 3-state enable input (OEA for A-side, OEB for B-side). Its edge-rate control circuitry and integrated 25-Ω series resistors suppress transmission-line reflections without external components.

The I_off feature actively disables outputs when V_CC = 0 V, limiting reverse current to ±1 µA and enabling safe hot-insertion in partially powered systems. Input thresholds (V_IL = 0.8 V, V_VIH = 2.0 V) and output levels (V_OL ≤ 0.55 V at 12 mA, V_OH ≥ 2.4 V at –15 mA) ensure full TTL interoperability.

Key Specifications

Pinout & Package

Package: QSOP-20 (DBQ drawing), 0.150" body width, gull-wing leads, RoHS-compliant green finish, MSL Level-2 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY74FCT2244CTQC, SN74FCT2244CTQCT offers identical performance and compatibility, while 74AC244SCX trades integrated termination and I_off for raw speed and lower static power-making it viable only in fully powered, well-terminated AC-system designs.

Availability

CY74FCT2244CTQC is available at Aetrix Electronics and suitable for memory address driving, clock distribution, and bus transceiver applications requiring stable component supply, industrial temperature range support, and legacy TTL interoperability.

Supply support for CY74FCT2244CTQC 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.

CY74FCT2244CTQC belongs to the TI FCT logic family, designed specifically for high-speed, low-noise, TTL-compatible buffering in industrial and computing infrastructure where signal integrity and power-down safety are critical.

FAQ

What is the maximum operating frequency supported by CY74FCT2244CTQC?

CY74FCT2244CTQC does not specify a maximum clock frequency directly, but its 4.1 ns maximum propagation delay (t_PLH/t_PHL) supports reliable operation in systems with data rates up to approximately 240 MHz under typical load conditions (CL = 50 pF). Actual usable frequency depends on board layout, termination, and fanout; for clock distribution, it is commonly deployed in sub-100 MHz synchronous buses with margin.

Does CY74FCT2244CTQC require external pull-up or pull-down resistors on its enable inputs?

No, CY74FCT2244CTQC does not require external pull-up or pull-down resistors on OEA or OEB. Its inputs are TTL-compatible with defined V_IL (≤0.8 V) and V_VIH (≥2.0 V), and internal input leakage is ±1 µA. Unused enables should be tied to V_CC (to disable outputs) or GND (to enable outputs) per TI's recommended operating conditions-no external resistors needed for proper logic-level assertion.

Can CY74FCT2244CTQC be used with 3.3-V logic systems?

CY74FCT2244CTQC is specified only for 4.75–5.25 V operation and is not 3.3-V tolerant. Its inputs require TTL-level thresholds (V_IL ≤ 0.8 V, V_VIH ≥ 2.0 V), and applying 3.3-V signals may result in marginal or undefined switching behavior. For 3.3-V systems, TI recommends the 74LVC244A or similar LVC-family buffers-not CY74FCT2244CTQC.

What is the purpose of the 25-Ω series resistor integrated into each output of CY74FCT2244CTQC?

The 25-Ω series resistor in each output of CY74FCT2244CTQC provides source termination for controlled-impedance transmission lines (e.g., 50-Ω PCB traces). It reduces signal reflections, overshoot, and ringing-especially critical in high-speed, long-trace, or multi-load configurations-without requiring discrete resistors. This simplifies layout, improves signal integrity, and lowers BOM cost.

How does the I_off feature of CY74FCT2244CTQC protect the device during partial power-down?

The I_off circuitry in CY74FCT2244CTQC disables all outputs when V_CC = 0 V, limiting reverse current flow through powered inputs to ±1 µA. This prevents damaging back-current from other active devices on shared buses, enabling safe hot-insertion and partial-power-down operation-critical in modular backplane or field-replaceable unit designs where subsystems power up/down independently.