Texas Instruments SN74ALS841FN

Overview

SN74ALS841FN from Texas Instruments is a 10-bit noninverting D-type latch with 3-state outputs, designed for bus interface applications in TTL-compatible systems. It operates from 0°C to 70°C, supports 5 V supply, delivers 24 mA low-level output drive, and features buffered control inputs and power-up high-impedance state for safe bus arbitration in data/address path expansion.

For engineers reviewing the SN74ALS841FN datasheet, SN74ALS841FN pinout, SN74ALS841FN application, or SN74ALS841FN equivalent, key selection criteria include its 10-bit transparent latch function, bus-structured pinout, 3-state output timing (tPLZ = 12 ns max), and compatibility with legacy ALS logic families in industrial control backplanes and memory subsystems.

Technical Context

The SN74ALS841FN implements ten independent transparent D-type latches with a common clock (C) and output control (OC) input. Its noninverting data path preserves logic polarity across all 10 bits, and OC enables simultaneous high-impedance output state without affecting internal latch operation or data retention.

Designed for direct bus driving, it features bus-organized pinout (inputs on one side, outputs on the other), buffered OC and C inputs to reduce DC loading, and guaranteed 24 mA IOL at VCC = 4.5 V - enabling robust drive into highly capacitive loads up to 50 pF with tPHL ≤ 13 ns.

Key Specifications

Pinout & Package

SN74ALS841FN uses a 24-pin plastic DIP (dual in-line package) with 300-mil width, designated FN package per TI documentation. Pin numbering follows standard DIP convention with notch-left orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit bus interface latch applications.

Compared with SN74ALS841FN, SN74ALS841N offers identical electrical behavior in a standard DIP package for plug-replaceability, while SN74AS841FN provides measurable speed and drive improvements at the cost of higher power and reduced noise margin - making SN74ALS841FN the optimal choice for stable, low-risk TTL bus interfacing where 13 ns timing suffices.

Availability

SN74ALS841FN is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory address latching, legacy system bus arbitration, digital I/O port expansion, and embedded controller bus buffering requiring stable component supply and long-term obsolescence management.

Supply support for SN74ALS841FN 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 U.S.-based semiconductor company founded in 1930, delivering analog and embedded processing solutions with emphasis on reliability, longevity, and industrial-grade qualification.

The SN74ALS841FN belongs to TI's 74ALS logic family, engineered for high-speed, low-power TTL-compatible bus interfacing in commercial-temperature embedded systems and legacy equipment upgrades.

FAQ

What is the maximum operating temperature range for the SN74ALS841FN?

The SN74ALS841FN is characterized for operation from 0°C to 70°C, conforming to commercial-grade temperature specifications. This range is explicitly defined in the SDAS059B datasheet and applies to all SN74-series variants including SN74ALS841FN. Operation outside this range may result in undefined timing or output behavior and is not supported by TI's production testing or warranty.

Does the SN74ALS841FN support 3.3 V operation?

No, the SN74ALS841FN does not support 3.3 V operation. Its recommended supply voltage is strictly 4.5 V to 5.5 V, and absolute maximum VCC is 7 V. The device uses bipolar ALS technology requiring 5 V rail compliance; applying 3.3 V will result in insufficient output voltage levels (VOH < 2.4 V) and unreliable switching, as confirmed by VIH/VIL thresholds and VOH/VOL specifications in the datasheet.

Is the SN74ALS841FN pin-compatible with the SN74ALS842FN?

No, the SN74ALS841FN is not pin-compatible with the SN74ALS842FN. While both are 24-pin FN-package devices, the SN74ALS842FN has inverting data inputs (D→Q inversion), resulting in different functional behavior and incompatible logic mapping. Their pinouts share identical physical layout but differ in signal assignment - e.g., SN74ALS842FN outputs reflect inverted input states, making direct substitution invalid without circuit redesign.

What is the purpose of the buffered OC and C inputs on the SN74ALS841FN?

The buffered OC (output control) and C (clock) inputs on the SN74ALS841FN reduce DC loading on upstream drivers by limiting input current to ≤0.1 mA, easing fanout requirements in dense bus systems. This buffering maintains signal integrity across multiple latch instances and ensures consistent timing margins, as verified by IIH/IIL specs and described in the "buffered control inputs" feature section of the SDAS059B datasheet.

Can the SN74ALS841FN be used in place of the SN74LS841?

Yes, the SN74ALS841FN can replace the SN74LS841 in most applications, offering improved speed (13 ns vs. 25 ns C→Q), lower power (ICC = 38–62 mA vs. ~70 mA), and stronger output drive (24 mA vs. 8 mA). However, verify that the system's VIH/VIL thresholds and noise margins accommodate ALS's slightly higher input thresholds (VIH = 2.0 V min) and faster edge rates before substitution.