Texas Instruments SN74AC7541RKSR

Overview

SN74AC7541RKSR from Texas Instruments is an octal buffer IC with open-drain CMOS outputs, dual active-low output enable inputs (OE1/OE2), 1.5V–6V supply operation, 24mA continuous output drive at 5V, and 11ns max propagation delay into 50pF load - used in level-shifting and LED-driving applications where wired-AND logic or voltage translation is required.

For engineers reviewing the SN74AC7541RKSR datasheet, SN74AC7541RKSR pinout, SN74AC7541RKSR application, or SN74AC7541RKSR equivalent, key selection criteria include open-drain output compatibility with 50Ω transmission lines, thermal performance in the 4.5mm × 2.5mm VQFN package, dual OE control logic, input voltage tolerance up to 6V, and compliance with −40°C to +125°C industrial temperature range.

Technical Context

The SN74AC7541RKSR implements eight independent non-inverting buffers sharing two active-low output enable inputs (OE1 and OE2), requiring both to be low for output activation. Its open-drain outputs support wired-AND bus configurations and external pull-up–based level shifting across voltage domains.

Each channel exhibits CMOS-compatible input thresholds (VIH/VIL varying with VCC), 9pF typical input capacitance, and output low-voltage (VOL) ≤0.1V at 24mA (5V supply). The device operates with input transition rates ≥20 ns/V above 3V supply and supports short-burst 75mA sink capability without damage when thermally managed.

Key Specifications

Pinout & Package

VQFN-20 (RKS) package: 4.5mm × 2.5mm body, wettable flank leads, exposed thermal pad (connectable to GND or left floating).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC7541RGER and SN74AHC7541PW, the SN74AC7541RKSR uniquely combines 6V input tolerance, 24mA drive at 5V, −40°C to +125°C qualification, and a compact 4.5mm × 2.5mm VQFN package - making it optimal for ruggedized, multi-voltage industrial interfaces where reliability and physical size are critical.

Availability

SN74AC7541RKSR is available at Aetrix Electronics and suitable for industrial control systems, automotive body electronics, and embedded HMI designs requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for SN74AC7541RKSR 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 specializing in analog, embedded processing, and logic solutions, with decades of experience in high-reliability industrial and automotive-grade components.

The SN74AC7541RKSR belongs to TI's AC logic family - designed for robust, wide-supply-voltage digital interfacing in demanding environments where noise immunity, thermal stability, and voltage-domain bridging are essential.

FAQ

What is the function of OE1 and OE2 on the SN74AC7541RKSR?

The SN74AC7541RKSR uses two active-low output enable inputs - OE1 (Pin 1) and OE2 (Pin 19). Both must be driven LOW simultaneously to activate all eight open-drain outputs. If either is HIGH, all outputs enter high-impedance state. This dual-enable architecture provides redundancy and enhances system-level fault containment in safety-critical interfaces.

Can the SN74AC7541RKSR drive a 50Ω transmission line directly?

Yes, the SN74AC7541RKSR is explicitly characterized to drive 50Ω transmission lines. At 5V supply and 24mA continuous sink current, its output low voltage remains ≤0.1V, ensuring clean signal integrity and minimal reflection - provided trace impedance is properly matched and layout follows controlled-impedance guidelines.

Does the SN74AC7541RKSR support 1.8V logic inputs when powered from 3.3V?

Yes. When VCC = 3.3V, the SN74AC7541RKSR accepts VIH ≥2.1V and VIL ≤0.9V per its Recommended Operating Conditions. A 1.8V logic HIGH (typically ~1.8V) falls below the 2.1V VIH threshold, so it will not register reliably. For 1.8V signaling, use VCC = 1.8V or add a level shifter - the device's 6V input tolerance does not relax VIH/VIL thresholds.

How should unused inputs be handled on the SN74AC7541RKSR?

All unused inputs on the SN74AC7541RKSR - including A1–A8, OE1, and OE2 - must be terminated to either VCC or GND. Floating CMOS inputs cause excessive current draw, oscillation, and potential device malfunction. TI recommends 10kΩ pull-up or pull-down resistors for unasserted enables or unused data inputs to ensure stable logic states.

What is the role of the thermal pad on the SN74AC7541RKSR (RKS package)?

The exposed thermal pad on the SN74AC7541RKSR serves two purposes: thermal dissipation (reducing junction-to-board resistance to 40.4°C/W) and EMI suppression. It may be connected to the PCB's GND plane for improved grounding or left floating - but must never be connected to VCC or signal nets. Solder mask opening and proper stencil design are critical for reliable reflow attachment.