Texas Instruments SN74LS365AN

Overview

SN74LS365AN from Texas Instruments is a hex bus driver with 3-state outputs, designed for bidirectional data bus interfacing in TTL logic systems. It features two independent 3-state control inputs (1G, 2G), six non-inverting buffer channels (1A–6A → 1Y–6Y), and operates over 0°C to 70°C. It is used in legacy industrial control backplanes and microprocessor address/data bus isolation.

For engineers reviewing the SN74LS365AN datasheet, SN74LS365AN pinout, SN74LS365AN application, or SN74LS365AN equivalent, key selection criteria include its dual 3-state enable architecture, TTL-compatible input thresholds, guaranteed 24mA output drive capability, and PDIP-16 packaging for through-hole prototyping and repair.

Technical Context

The SN74LS365AN implements six independent non-inverting buffers, each with output-enable control grouped into two sets: channels 1Y–3Y share enable 1G, and 4Y–6Y share enable 2G. This allows selective tri-stating of upper/lower bus segments without external gating logic.

It uses standard bipolar TTL circuitry with Schottky-clamped transistors, delivering typical propagation delay of 15 ns (max 25 ns) at V_CC = 5V, and supports fan-out of 20 LS-TTL loads. Input clamping diodes provide ESD protection per MIL-STD-883 Class 3015.7.

Key Specifications

Pinout & Package

SN74LS365AN is supplied in a 16-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width and standard 0.1-inch pin pitch. Pin 1 is marked by a notch or dot; the package is RoHS-compliant with NiPdAu lead finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar hex 3-state buffer applications.

Compared with SN74LS244N and SN74LS367AN, the SN74LS365AN offers optimal channel count and polarity for 6-bit unidirectional bus segmentation, with no PCB redesign needed versus the SN74LS367AN and lower component count than using two SN74LS365ANs to match SN74LS244N's octal capacity.

Availability

SN74LS365AN is available at Aetrix Electronics and suitable for industrial control backplanes, legacy test equipment refurbishment, and microprocessor bus isolation requiring stable component supply and long-term obsolescence management.

Supply support for SN74LS365AN 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 ICs, with decades of heritage in TTL and LS-TTL product families.

The SN74LS365AN belongs to TI's legacy 74LS logic series, engineered for reliability in commercial-temperature industrial and instrumentation applications where proven timing behavior and mechanical robustness outweigh ultra-low power or high-speed requirements.

FAQ

What is the maximum clock frequency supported by SN74LS365AN?

The SN74LS365AN is not a clocked device-it has no internal clock and functions as a combinational buffer. Its usable data rate is determined by propagation delay (25 ns max) and system setup/hold timing. In practice, it reliably supports asynchronous bus cycles up to 20 MHz with proper trace length control and termination. The SN74LS365AN does not impose a hard clock limit but relies on external timing control.

Can SN74LS365AN drive LEDs directly?

Yes-the SN74LS365AN can sink up to 24 mA per output, sufficient to drive standard 5-mm LEDs (typically 10–20 mA) with appropriate current-limiting resistors. For example, with V_CC = 5 V and LED V_F = 2.1 V, a 150 Ω resistor yields ~19 mA. Always verify voltage drop and thermal derating; the SN74LS365AN is not optimized for continuous LED current but handles brief indicator duty cycles robustly.

Is SN74LS365AN pin-compatible with SN74LS367AN?

Yes-SN74LS365AN and SN74LS367AN share identical PDIP-16 pinouts, supply requirements, and enable logic. The only functional difference is output polarity: SN74LS365AN provides six non-inverting buffers, while SN74LS367AN offers three non-inverting and three inverting channels. They are direct PCB replacements where signal inversion is acceptable or compensated in firmware.

Does SN74LS365AN support hot-swap insertion?

The SN74LS365AN has no built-in hot-swap protection, but its 3-state outputs and input clamping diodes allow safe insertion into powered backplanes when 1G and 2G are held HIGH (disabled) prior to connection. System-level current limiting and sequencing are required. The SN74LS365AN's robust input structure withstands brief bus conflicts during insertion, unlike CMOS equivalents.

What is the recommended decoupling for SN74LS365AN?

TI recommends a 0.1 µF ceramic capacitor placed within 5 mm of pins 16 (V_CC) and 8 (GND), plus a bulk 4.7 µF–10 µF electrolytic/tantalum capacitor per 5–10 ICs on the same 5 V rail. This suppresses switching noise from simultaneous output transitions-critical because the SN74LS365AN exhibits high di/dt during 24-mA output slewing. Poor decoupling causes V_CC droop and timing violations.