Texas Instruments CY74FCT2240CTQCT

Overview

CY74FCT2240CTQCT from Texas Instruments is an octal noninverting buffer/line driver with 3-state outputs, 25-Ω on-chip series termination resistors per output, 4.1 ns max propagation delay at 5 V, ±15 mA output drive, and I_off support for partial-power-down operation. It serves as a memory address driver, clock driver, or bus transceiver in TTL/CMOS/NMOS mixed-signal systems.

For engineers reviewing the CY74FCT2240CTQCT datasheet, CY74FCT2240CTQCT pinout, CY74FCT2240CTQCT application, or CY74FCT2240CTQCT equivalent, key selection criteria include 3-state timing (t_PZH/t_PHZ ≤ 5.2 ns), output impedance matching (20–40 Ω), I_off leakage (< ±1 µA at V_CC = 0 V), and SSOP-20 thermal performance (θ_JA = 68°C/W).

Technical Context

This device implements dual 4-bit noninverting buffers with independent 3-state enable controls (OEA and OEB), each driving four outputs (OA0–OA3 and OB0–OB3). Its edge-rate control circuitry shapes output transitions to suppress transmission-line reflections without external termination.

The integrated 25-Ω series resistors are placed between internal output drivers and pins, enabling direct connection to 50-Ω PCB traces. I_off functionality ensures high-impedance isolation of outputs when V_CC = 0 V, preventing backflow current during system power sequencing.

Key Specifications

Pinout & Package

Package: SSOP-20 (DBQ), 0.635 mm pitch, body size 7.2 × 5.3 mm, 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 octal 3-state buffer applications.

Compared with SN74FCT2240CTSOCT and 74AC240SCX, CY74FCT2240CTQCT uniquely combines SSOP-20 compactness, integrated 25-Ω termination, and I_off protection - making it optimal for space-constrained, high-noise, or mixed-power-domain designs where board-level termination and safe power sequencing are mandatory.

Availability

CY74FCT2240CTQCT is available at Aetrix Electronics and suitable for memory address buffering, clock distribution, bus transceiver interfaces, and legacy system glue logic requiring stable component supply across industrial temperature ranges (–40°C to 85°C).

Supply support for CY74FCT2240CTQCT 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 connectivity solutions for industrial, automotive, and personal electronics markets.

The CY74FCT family delivers 5-V TTL-compatible logic with FCT-series speed, low power, and enhanced noise immunity - designed specifically for high-reliability 5-V digital systems requiring robust signal integrity and mixed-technology interoperability.

FAQ

What is the maximum operating frequency supported by CY74FCT2240CTQCT?

CY74FCT2240CTQCT does not specify a maximum clock frequency in its datasheet because it is a combinational buffer, not a clocked device. However, its 4.1 ns propagation delay enables reliable operation with signal edges up to ~200 MHz in well-terminated 50-Ω environments. Actual usable frequency depends on trace length, load capacitance, and termination - the integrated 25-Ω resistors help maintain signal integrity at these speeds without external components. For CY74FCT2240CTQCT, timing margins are validated across –40°C to 85°C.

Does CY74FCT2240CTQCT support hot-swap or partial-power-down operation?

Yes, CY74FCT2240CTQCT supports partial-power-down via its I_off circuitry. When V_CC = 0 V, output leakage remains within ±1 µA even with up to 4.5 V applied at outputs - preventing damaging back-current during hot-insertion or staged power-up/down sequences. This feature is explicitly tested and guaranteed per JEDEC JESD78, making CY74FCT2240CTQCT suitable for modular backplane and field-replaceable unit designs where power domains are sequenced independently.

What is the purpose of the dual 3-state enable inputs (OEA and OEB) on CY74FCT2240CTQCT?

The dual 3-state enables (OEA for OA0–OA3, OEB for OB0–OB3) allow independent control of two 4-bit output groups. This enables flexible bus segmentation - for example, using OA outputs for address lines and OB outputs for control signals, each gated separately during different phases of a memory cycle. In CY74FCT2240CTQCT, this architecture reduces need for additional logic gates or multiplexers in systems requiring time-multiplexed or isolated data paths, improving timing predictability and simplifying PCB routing.

Can CY74FCT2240CTQCT replace older 74LS240 devices in existing designs?

Yes, CY74FCT2240CTQCT is functionally and pinout-compatible with 74LS240, offering direct drop-in replacement in most 5-V TTL systems. It improves upon LS-series with faster propagation (4.1 ns vs ~25 ns), lower ICC (0.2 mA vs ~25 mA), integrated 25-Ω termination, and superior ESD ratings (2000-V HBM vs ~200-V). No PCB changes are required for CY74FCT2240CTQCT substitution, though decoupling capacitor placement should follow TI's SSOP layout guidelines to maintain noise performance.

What package type and dimensions does CY74FCT2240CTQCT use?

CY74FCT2240CTQCT uses a 20-pin SSOP (Shrink Small Outline Package) with drawing code DBQ, measuring 7.2 mm × 5.3 mm × 1.75 mm (L × W × H) and 0.635 mm lead pitch. It is supplied in tape-and-reel format (2500 units per reel) with MSL Level-2 moisture sensitivity (260°C peak reflow, 1-year floor life). The pin-1 quadrant is Q1 per TI's tape orientation specification, and the top-side marking is "FCT2240C".