Texas Instruments SN74ACT7541RKSR

Overview

SN74ACT7541RKSR from Texas Instruments is an octal buffer/driver IC with open-drain CMOS outputs, TTL-compatible inputs, and dual active-low output enable (OE1/OE2) control. It operates from 4.5V to 5.5V, delivers up to 24mA continuous output drive at 5V, and supports short-burst 75mA sink capability-enabling direct interface with LEDs, relays, and 50Ω transmission lines in industrial control and level-shifting applications.

For engineers reviewing the SN74ACT7541RKSR datasheet, SN74ACT7541RKSR pinout, SN74ACT7541RKSR application, or SN74ACT7541RKSR equivalent, key selection criteria include open-drain output configuration, dual OE logic coordination, 9.6ns max propagation delay (5V/50pF), thermal performance in RKS VQFN package, and compatibility with 5V TTL signal domains.

Technical Context

The SN74ACT7541RKSR implements eight independent non-inverting buffers sharing two active-low output enable inputs (OE1 and OE2), both of which must be low for any output to drive low; otherwise all outputs enter high-impedance state. Its open-drain architecture enables wired-AND bus configurations and flexible level translation via external pull-up networks.

It features TTL-compatible input thresholds (VIL ≤ 0.8V, VIH ≥ 2V at 4.5–5.5V), 8pF typical input capacitance, and 14pF typical output capacitance-supporting fast edge rates (≤20 ns/V) while maintaining noise immunity. Thermal resistance in the RKS package is RθJA = 67.7°C/W and RθJB = 40.4°C/W, enabling reliable operation across –40°C to 125°C ambient.

Key Specifications

Pinout & Package

The SN74ACT7541RKSR is housed in a 20-pin VQFN (RKS) package measuring 4.5mm × 2.5mm with an exposed thermal pad. The package supports fine-pitch PCB layout and enhanced thermal dissipation via bottom-side thermal pad connection to GND or floating (not connected to other signals).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC8T245RHLR and SN74AHC1G07DBVR, the SN74ACT7541RKSR uniquely combines octal density, dual active-low OE coordination, 75mA pulsed sink, and industry-standard RKS VQFN packaging-making it optimal for compact, high-reliability 5V open-drain bus and load-driving applications without added logic overhead.

Availability

SN74ACT7541RKSR is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and embedded control systems requiring stable component supply, extended temperature operation, and RoHS-compliant packaging.

Supply support for SN74ACT7541RKSR 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 and embedded processing solutions, with decades of expertise in logic, interface, and power management ICs.

The SN74ACT7541RKSR belongs to TI's ACT family of advanced CMOS logic devices, designed specifically for high-speed, low-noise, 5V industrial and automotive applications demanding robust ESD performance and wide temperature operation.

FAQ

What is the function of OE1 and OE2 on the SN74ACT7541RKSR?

The SN74ACT7541RKSR uses two active-low output enable inputs-OE1 and OE2-that must both be driven LOW simultaneously to activate the open-drain outputs. If either OE1 or OE2 is HIGH, all eight Y outputs enter high-impedance state regardless of input states. This dual-enable architecture provides fail-safe control and redundancy in safety-critical logic paths. The SN74ACT7541RKSR datasheet confirms this behavior in the Function Table (Section 7.4).

Can the SN74ACT7541RKSR drive a 12V LED string?

Yes-the SN74ACT7541RKSR can drive a 12V LED string when used with an external pull-up resistor to 12V, leveraging its open-drain output structure. The device itself only sinks current (up to 75mA pulsed) and does not source voltage; therefore, the 12V rail must be externally supplied. Ensure the LED forward voltage plus series resistor drop stays within the SN74ACT7541RKSR's absolute maximum output voltage rating (VCC + 0.5V = 6V), meaning the output node voltage may exceed VCC but must not exceed 6V relative to GND. The SN74ACT7541RKSR's output clamp diodes protect against transient overvoltage.

What is the maximum capacitive load the SN74ACT7541RKSR can drive while meeting datasheet timing specs?

The SN74ACT7541RKSR is characterized for CL = 50pF in its switching specifications (e.g., tPHL = 9.6ns max at 5V). While larger capacitive loads can be driven, timing parameters will degrade-propagation delay increases approximately linearly with load capacitance. For designs requiring guaranteed 9.6ns max delay, keep total output node capacitance ≤ 50pF, including trace, probe, and receiver input capacitance. The SN74ACT7541RKSR application note recommends adding a series resistor for loads >50pF to limit peak current and prevent damage.

Does the SN74ACT7541RKSR require external pull-up resistors on its outputs?

Yes-open-drain outputs like those on the SN74ACT7541RKSR cannot actively drive HIGH; they only sink current to GND. To establish a defined HIGH logic level, each Yx output must be connected to a positive supply (e.g., 5V or 3.3V) through an external pull-up resistor. Typical values range from 1kΩ to 10kΩ depending on speed, power, and noise requirements. The SN74ACT7541RKSR datasheet recommends 10kΩ for general-purpose use, balancing rise time and static current consumption.

Is the thermal pad on the SN74ACT7541RKSR package required to be connected to ground?

The thermal pad on the SN74ACT7541RKSR (RKS VQFN) may be connected to GND or left floating, but TI strongly recommends connecting it to the PCB ground plane to maximize thermal performance and reduce junction temperature. Doing so lowers RθJB to 40.4°C/W and improves reliability under sustained 24mA output loading. The SN74ACT7541RKSR datasheet explicitly states "Do not connect to any other signal or supply"-only GND or no connection is acceptable. No solder mask opening is needed beneath the pad for standard assembly.