Product Overview
SN74LS05 Low-Power Schottky Hex Inverter with Open-Collector Outputs
Condition
Unused new old stock (NOS). Lead legs show surface tarnish and oxidation consistent with age and storage. Package markings are crisp and legible: SN74LS05N, Texas Instruments logo, and El Salvador with vintage date codes including 7845A, 7906A, and 8001A. Sold individually as a single integrated circuit.
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Product Overview
Engineered for digital logic designs, the Texas Instruments SN74LS05N provides six independent inverting gates with open-collector outputs in a 14-pin plastic DIP package. The Low-Power Schottky (LS) architecture delivers reliable TTL switching speeds with reduced power dissipation on a standard 5V logic rail. Open-collector outputs allow wired-AND connections, voltage level shifting, and direct driving of indicator LEDs or relays up to 5.5V when paired with an external pull-up resistor.
Key Features
- Six independent inverting logic gates in a single 14-pin dual in-line package (DIP-14)
- Low-Power Schottky TTL (74LS) technology for balanced switching speed and low power consumption
- Open-collector output configuration requires external pull-up resistors for active-high logic output
- Supports wired-AND bus configurations and multi-voltage logic interfacing
- Standard 5.0V nominal logic supply voltage with 4.75V to 5.25V operating range
- Low-level output sink current rating of 8 mA
- Maximum off-state output voltage rating of 5.5 V
- Standard 0.1-inch through-hole pin spacing for breadboards and printed circuit boards
Applications
- Restoring and repairing vintage 1970s and 1980s computer motherboards, arcade boards, and industrial controller cards
- Breadboard prototyping and digital logic experiments in maker, student, and hobbyist electronics projects
- Interfacing 5V TTL systems with higher-voltage digital circuits or open-collector bus lines
- Driving low-current LED indicators or small relay coils directly from digital logic circuits
Frequently Asked Questions
Why does the SN74LS05N require pull-up resistors?
The open-collector output design can sink current to ground when active low, but it cannot actively source current when high. An external pull-up resistor connected to the desired logic voltage is required to pull the output line high when the inverter gate is off.
Can this IC be used to replace a standard 7405 or 74LS05?
Yes. The SN74LS05N uses the industry-standard 7405 pinout and open-collector output structure, providing a direct drop-in replacement in circuits designed for standard 7405 or 74LS05 hex inverters.
How should tarnished pins be handled before soldering or socketing?
Vintage NOS components naturally develop surface oxidation over decades of storage. Lightly burnishing the pins with a fine abrasive pad, fluxing generously, or tinning the leads before installation ensures solid solder joints and reliable socket contact.
Why buy individual vintage ICs here instead of bulk surplus lots?
Bulk component lots often force you to buy dozens of unknown parts when you only need one authentic piece for a specific repair. Here, you get individually inspected vintage Texas Instruments stock with clear date codes, so you know exactly what is going into your board. Orders ship for an $8 flat rate, or free once your order passes $28, leaving our Idaho warehouse the same or next business day.
Open-collector logic is the quiet workhorse of vintage digital design, letting multiple outputs share a single wire without fighting for control. Plug this into your socket, pull the line high, and watch that classic board run exactly the way its designers intended.
