Texas Instruments CD74HCT541E

Overview

CD74HCT541E from Texas Instruments is a non-inverting octal buffer and line driver with three-state outputs, designed for bidirectional bus interfacing in 5-V TTL-compatible digital systems. It features 8 data inputs (A0–A7), dual output-enable controls (OE1, OE2), 15-LSTTL load drive capability, 9 ns typical propagation delay at 5 V/15 pF, and operation across –55°C to +125°C.

For engineers reviewing the CD74HCT541E datasheet, CD74HCT541E pinout, CD74HCT541E application, or CD74HCT541E equivalent, this device is selected for high-reliability bus buffering where LSTTL compatibility, wide temperature range, and low-power CMOS logic are required - especially in industrial control backplanes, legacy system upgrades, and radiation-tolerant military subsystems.

Technical Context

The CD74HCT541E implements dual independent three-state enable logic: outputs enter high-impedance when either OE1 or OE2 is HIGH, and drive valid logic only when both enables are LOW. Its HCT logic family ensures direct compatibility with standard TTL input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V) while maintaining CMOS-level quiescent current (ICC ≤ 160 μA).

Internally, it uses buffered inputs to reduce capacitive loading and improve noise immunity (NIL/NIL = 30% of VCC), and its balanced transition times minimize skew across all eight channels. The device supports mixed-voltage system interfacing via strict 4.5–5.5 V supply operation and guarantees 6 mA sink/source per output under TTL loads.

Key Specifications

Pinout & Package

CD74HCT541E is supplied in a 20-pin plastic dual in-line package (PDIP-N), with 25.40 mm × 6.35 mm body size, through-hole mounting, and industry-standard pin spacing (2.54 mm). Pin 1 is located at the left end of the top row, identified by a notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HCT541E, SN74HCT541N offers identical performance with enhanced manufacturing traceability, while 74ACT541PC trades extended temperature capability for higher speed and drive strength - making CD74HCT541E the optimal choice for ruggedized, long-lifecycle deployments.

Availability

CD74HCT541E is available at Aetrix Electronics and suitable for industrial backplane interfaces, military data acquisition systems, and automotive engine control units requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD74HCT541E 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 with emphasis on reliability, longevity, and industrial/military qualification.

The CD74HCT541E belongs to TI's legacy high-speed CMOS logic family, engineered specifically for backward compatibility with TTL systems while delivering CMOS power efficiency and extended temperature resilience.

FAQ

What is the maximum clock frequency supported by CD74HCT541E?

The CD74HCT541E is not a clocked device but a combinational buffer; its usable frequency depends on propagation delay and load. With 9 ns typical tPLH/tPHL into 15 pF, it supports clean signal edges up to ~35 MHz in bus applications. For precise timing analysis, use tPLH/tPHL values from the datasheet's Switching Characteristics table at your specific VCC and CL conditions. CD74HCT541E does not have an internal clock or maximum toggle rate specification.

Can CD74HCT541E be used with a 3.3-V microcontroller interface?

No - CD74HCT541E requires 4.5–5.5 V supply and is not 3.3-V tolerant. Its inputs are designed for TTL thresholds (VIH ≥ 2.0 V), but applying 3.3 V directly to VCC violates the minimum supply rating. For 3.3-V systems, use a level-shifting buffer such as SN74LVC541A. CD74HCT541E must operate at 5 V to meet its specified VIH/VIL, drive strength, and timing.

How do OE1 and OE2 interact in CD74HCT541E?

In CD74HCT541E, outputs go high-impedance if *either* OE1 *or* OE2 is HIGH; both OE1 and OE2 must be LOW for Y0–Y7 to actively drive. This dual-enable structure allows flexible bus arbitration - e.g., OE1 controlled by main controller, OE2 by watchdog or fail-safe circuit. The truth table in section 7.3 confirms that any HIGH on OE1 or OE2 forces Z-state regardless of input states. CD74HCT541E behavior is identical to CD74HC541E except for input threshold compatibility.

Is CD74HCT541E suitable for space-constrained PCB layouts?

CD74HCT541E uses a through-hole PDIP-20 package (25.4 mm × 6.35 mm), which occupies significantly more board area than surface-mount alternatives like SOIC or TSSOP. For space-constrained designs, consider CD74HCT541M96 (SOIC-20) or CD74HCT541PWR (TSSOP-20). However, CD74HCT541E remains preferred where mechanical robustness, hand-soldering, or legacy socket compatibility is required. Its pin pitch (2.54 mm) simplifies manual routing.

Does CD74HCT541E require external pull-up resistors on its outputs?

No - CD74HCT541E outputs are push-pull CMOS and do not require external pull-ups in active drive mode. When in three-state (high-Z), external pull-ups may be needed only if bus lines must default to a known logic level during disable. The device itself provides no internal pull-ups; all I/O are strictly driven or tri-stated. Always bypass VCC with a 0.1-μF ceramic capacitor near pin 20, as specified in section 8 of the datasheet for CD74HCT541E.