onsemi SN74LS05N

Overview

SN74LS05N from Texas Instruments is a 14-pin PDIP-packaged hex inverter IC with open-collector outputs, designed for TTL-compatible logic level translation and wired-OR bus interfacing. It operates at 4.75–5.25 V, delivers 8 mA sink current per output, exhibits 15–32 ns propagation delay, and supports 0°C to 70°C industrial temperature range - commonly used in address decoding, bus arbitration, and level-shifting circuits.

For engineers reviewing the SN74LS05N datasheet, pinout, applications, or equivalent options, key selection criteria include open-collector drive capability, TTL input compatibility, low-power LS-series quiescent current (1.2–2.4 mA), thermal performance (θ_JA = 80°C/W), and legacy DIP package suitability for through-hole prototyping and industrial control backplanes.

Technical Context

The SN74LS05N implements six independent inverting buffers with open-collector NPN output stages requiring external pull-up resistors. Its internal circuitry uses bipolar Schottky-clamped transistors to achieve LS-series speed-power trade-offs, with input thresholds of V_IL = 0.7 V and V_IH = 2.0 V, and guaranteed VOL ≤ 0.4 V at I_OL = 8 mA.

It interfaces directly with standard TTL and LS logic families, supports active-low wired-OR and active-high wired-AND configurations, and avoids internal output contention due to its non-sourcing architecture - making it suitable for shared-bus termination and interrupt line aggregation without external diodes.

Key Specifications

Pinout & Package

SN74LS05N is supplied in a 14-pin plastic dual in-line package (PDIP-N), 0.300-inch wide body, with 0.100-inch lead pitch and through-hole mounting. Pin 1 is located at the left end of the top row when viewed from the top with notch or dot oriented left.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN7405N, SN74LS05N reduces power consumption by ~60% and improves propagation delay consistency, while retaining identical pinout and open-collector functionality; versus SN74LS04N, it trades off sourcing capability for wired-logic flexibility - making SN74LS05N uniquely suited for shared-bus and mixed-voltage interface roles.

Availability

SN74LS05N is available at Aetrix Electronics and suitable for industrial control panels, legacy system repairs, and educational electronics labs requiring stable component supply and long-term obsolescence resilience.

Supply support for SN74LS05N 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 founded in 1930, delivering analog, embedded processing, and logic solutions with emphasis on reliability, longevity, and industrial-grade qualification.

The SN74LS05N belongs to TI's legacy 74LS logic family, engineered for cost-effective, robust digital interfacing in commercial and industrial systems where compatibility, thermal stability, and through-hole manufacturability remain essential.

FAQ

What is the maximum sink current per output of the SN74LS05N?

The SN74LS05N guarantees a minimum output sink current (I_OL) of 4 mA and a typical value of 8 mA per channel under recommended operating conditions (V_CC = 5 V, T_A = 25°C). This rating ensures reliable driving of TTL inputs, small-signal relays, or indicator LEDs without external buffering - and is validated across the full 0°C to 70°C operating range. The SN74LS05N must not be operated beyond its absolute maximum I_OL limit of 20 mA per output.

Does the SN74LS05N require external pull-up resistors on its outputs?

Yes, the SN74LS05N requires external pull-up resistors on all six open-collector outputs (pins 2, 4, 6, 8, 10, 12) to assert a HIGH logic level. Without pull-ups, outputs remain floating when inactive. Typical values range from 1 kΩ (for fast rise times with capacitive loads) to 10 kΩ (for low power); selection depends on load capacitance, desired rise time, and supply voltage. The SN74LS05N itself does not provide internal pull-ups.

Can the SN74LS05N be used to interface with 3.3 V logic systems?

The SN74LS05N is not recommended for direct connection to 3.3 V logic inputs because its TTL-compatible input thresholds (V_IL = 0.7 V, V_IH = 2.0 V) may misinterpret 3.3 V logic HIGHs as marginal or invalid, especially under noise or temperature variation. While its outputs can sink 3.3 V logic LOWs safely, level-shifting circuitry or a dedicated 3.3 V–5 V translator is required for reliable bidirectional interfacing. The SN74LS05N is optimized for 5 V TTL ecosystems.

Is the SN74LS05N pin-compatible with other 74xx hex inverters?

Yes, the SN74LS05N shares identical pinout and functional assignment with SN7405N, SN74S05N, and SN74LS04N - all 14-pin DIP devices with inputs on odd pins (1,3,5,9,11,13) and outputs on even pins (2,4,6,8,10,12), plus V_CC (pin 14) and GND (pin 7). However, SN74LS05N differs electrically: it uses open-collector outputs (unlike SN74LS04N's totem-pole), and has LS-series speed/power characteristics distinct from 7405 (standard TTL) or 74S05 (Schottky).

What is the thermal resistance (θ_JA) of the SN74LS05N in its PDIP package?

The SN74LS05N in the plastic DIP (N) package has a junction-to-ambient thermal resistance (θ_JA) of 80°C/W, measured under standard JEDEC test conditions (single-layer board, no airflow). This value enables thermal estimation for continuous operation: at 6.6 mA ICCL and 8 mA I_OL worst-case, power dissipation remains below 50 mW, resulting in <4°C junction rise above ambient - confirming suitability for convection-cooled industrial enclosures without heatsinking.