Texas Instruments SN74ALS35AD

Overview

SN74ALS35AD from Texas Instruments is a hex noninverting buffer with open-collector outputs, designed for wired-OR/AND logic interfacing in TTL-compatible systems. It operates at 4.5–5.5 V, delivers 8 mA low-level output current, exhibits 2–14 ns propagation delay (tPHL), and is rated for 0°C to 70°C operation - commonly used in bus interface, level translation, and LED drive circuits.

For engineers reviewing the SN74ALS35AD datasheet, SN74ALS35AD pinout, SN74ALS35AD application, or SN74ALS35AD equivalent, key selection criteria include open-collector drive capability, TTL input compatibility, SOIC-14 thermal and layout constraints, and wired-logic implementation requirements.

Technical Context

The SN74ALS35AD implements six independent noninverting buffers (Y = A) using Advanced Low-Power Schottky (ALS) bipolar technology. Each output stage is an open-collector NPN transistor requiring external pullup resistors to define VOH and enable wired-logic functions.

It supports active-low wired-OR and active-high wired-AND configurations by connecting multiple outputs to a shared pullup. Its input thresholds (VIH = 2 V, VIL = 0.8 V) ensure robust noise margin against TTL logic families, while its IOL = 8 mA rating enables direct driving of LEDs or small-signal loads.

Key Specifications

Pinout & Package

SN74ALS35AD is housed in a 14-pin SOIC (Small Outline Integrated Circuit) package, 3.9 mm wide, 8.75 mm long, with 1.27 mm lead pitch and maximum height of 1.75 mm - suitable for high-density PCB layouts and automated SMT assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar hex noninverting buffer applications.

Compared with SN74LS35N and SN74F35N, the SN74ALS35AD delivers optimal balance of speed (2–14 ns tPHL), power efficiency (ICCL = 4.1–6.3 mA), and TTL compatibility - making it the preferred choice for general-purpose buffered interfacing in commercial-grade systems.

Availability

SN74ALS35AD is available at Aetrix Electronics and suitable for industrial bus interface, LED status indication, level translation interface, and TTL-to-discrete logic adapter applications requiring stable component supply and long-term obsolescence management.

Supply support for SN74ALS35AD 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 innovator founded in 1930, delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74ALS35AD belongs to TI's legacy 74ALS logic family - engineered for improved speed-power tradeoffs over 74LS while maintaining full TTL compatibility and robustness in commercial environments.

FAQ

What is the primary function of the SN74ALS35AD?

The SN74ALS35AD is a hex noninverting buffer with open-collector outputs, performing Y = A logic for each of six independent channels. It is used to isolate, restore, and drive signals in TTL-based systems - especially where wired-OR/AND logic, level translation, or LED driving is needed. Its open-collector architecture requires external pullup resistors to define logic HIGH states.

Does the SN74ALS35AD require external pullup resistors?

Yes, the SN74ALS35AD requires external pullup resistors on all six open-collector outputs (1Y–6Y) to establish a defined VOH level and enable proper logic operation. Without pullups, outputs remain floating in the HIGH state and cannot drive downstream TTL inputs reliably. Typical values range from 1 kΩ to 10 kΩ depending on load capacitance and speed requirements.

What is the maximum output sink current for the SN74ALS35AD?

The SN74ALS35AD guarantees a minimum low-level output current (IOL) of 8 mA per channel at VOL ≤ 0.5 V under recommended operating conditions (VCC = 4.5 V, TA = 0°C to 70°C). This allows direct driving of standard LEDs or fanout to multiple TTL inputs without additional buffering stages.

Can the SN74ALS35AD be used in place of the SN74LS35N?

The SN74ALS35AD is pin-compatible and functionally equivalent to the SN74LS35N, but offers faster propagation delays (tPHL down to 2 ns vs. 25 ns), lower power consumption (ICCL ≈ 5.2 mA vs. 19 mA), and improved noise margins. No PCB changes are required, though pullup resistor values may need minor optimization due to differing output impedance.

What package type does the SN74ALS35AD use?

The SN74ALS35AD uses a 14-pin SOIC (Small Outline Integrated Circuit) package designated as "D" by Texas Instruments - measuring 8.75 mm × 3.91 mm with 1.27 mm lead pitch and maximum height of 1.75 mm. It is RoHS-compliant, moisture-sensitive level 1, and supplied in tubes of 50 units.