Texas Instruments CD74FCT541E

Overview

CD74FCT541E from Texas Instruments is a BiCMOS octal noninverting buffer/driver with 3-state outputs, designed for bus line driving and memory address register buffering. It delivers 64-mA sink current, limits output voltage swing to 3.7 V, features dual active-low output-enable inputs (OE1/OE2), and operates across 4.75–5.25 V at 0°C to 70°C.

For engineers reviewing the CD74FCT541E datasheet, CD74FCT541E pinout, CD74FCT541E application, or CD74FCT541E equivalent, key selection criteria include 3-state control logic, BiCMOS EMI suppression, output current capability, thermal resistance (69°C/W), and PDIP-20 package compatibility with legacy through-hole designs.

Technical Context

The CD74FCT541E implements a two-input AND gate for 3-state control with active-low OE1 and OE2: either high forces all eight Y outputs into high-impedance. Its BiCMOS output stage combines bipolar and CMOS transistors to clamp VOH at ~VCC – 1.3 V, limiting swing to 0–3.7 V under 5-V operation.

This architecture reduces power-bus ringing and VCC/ground bounce during simultaneous switching while enabling 64-mA sink per output and 15-mA source. Propagation delay is 2–8 ns, enable/disable times are 2–10 ns, and input transition rate tolerance is up to 10 ns/V.

Key Specifications

Pinout & Package

CD74FCT541E is supplied in a 20-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width and through-hole mounting. Pin 1 is marked by a notch or dot; pin 10 is GND and pin 20 is VCC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal 3-state buffer applications.

Compared with SN74F244N and 74ACT244PC, the CD74FCT541E uniquely balances high sink current, controlled output swing, and latch-up immunity-making it optimal for legacy 5-V bus systems where signal integrity and reliability outweigh raw speed.

Availability

CD74FCT541E is available at Aetrix Electronics and suitable for memory address buffering, microprocessor bus interfacing, and industrial I/O expansion requiring stable component supply and long-term obsolescence management.

Supply support for CD74FCT541E 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 founded in 1930, delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The CD74FCT541E belongs to TI's FCT logic family-designed specifically for high-drive, low-noise 5-V digital interfacing with BiCMOS process advantages over standard TTL or CMOS.

FAQ

What is the recommended pull-up resistor value for OE pins on the CD74FCT541E during power-up?

The CD74FCT541E datasheet specifies that OE should be tied to VCC via a pull-up resistor to ensure high-impedance state at power-up. The minimum resistor value depends on the driver's current-sinking capability; for standard 5-V operation, a 4.7-kΩ resistor is commonly used to limit current to <1 mA while maintaining robust noise immunity. This ensures all Y outputs remain safely disabled until system firmware asserts valid OE control.

Does the CD74FCT541E support mixed-voltage operation, such as 3.3-V inputs with 5-V VCC?

Yes, the CD74FCT541E accepts 3.3-V logic inputs when powered at 5 V: its VIH is 2.0 V min and VIL is 0.8 V max, fully compatible with 3.3-V CMOS/TTL output levels. However, outputs swing 0–3.7 V-not rail-to-rail-so downstream 3.3-V receivers must tolerate this VOH. The device does not support VCC < 4.75 V, so 3.3-V supply operation is not permitted.

How does the CD74FCT541E reduce electromagnetic interference compared to standard TTL buffers?

The CD74FCT541E reduces EMI by limiting output voltage swing to 0–3.7 V using a BiCMOS output stage that clamps VOH to ~VCC – 1.3 V. This lowers dV/dt during transitions, cuts high-frequency harmonics, and suppresses power-bus ringing. Unlike standard TTL buffers with full 5-V swings, this design minimizes VCC bounce and ground bounce during simultaneous switching of all eight outputs-critical in dense PCB layouts.

Can the CD74FCT541E drive LEDs directly, and what is the maximum series resistance for a 5-V supply?

Yes, the CD74FCT541E can drive LEDs directly via its Y outputs, leveraging its 64-mA sink capability. For a typical red LED (VF ≈ 1.8 V) at 10 mA, the series resistance is R = (3.7 V – 1.8 V)/0.01 A = 190 Ω. Using the absolute max 64 mA, minimum R = (3.7 V – 1.8 V)/0.064 A ≈ 30 Ω. Always verify LED forward voltage and derate for temperature; do not exceed 64 mA per output or 528 mA total GND current.

Is the CD74FCT541E pin-compatible with the CD74FCT244E, and what are the functional differences?

No, the CD74FCT541E is not pin-compatible with CD74FCT244E: the former has dual OE inputs (pins 1 and 19) and noninverting outputs, while the latter has single OE (pin 1) and inverting/noninverting pairs. Functionally, CD74FCT541E provides eight noninverting buffers with AND-gated 3-state control; CD74FCT244E offers four inverting + four noninverting buffers with single-enable. They share BiCMOS benefits but serve distinct logic architectures.