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Texas Instruments SN7406N HP 1820-0471 TTL Hex Inverter Open-Collector Buffer Driver DIP-14 Arcade Computer Logic IC

ICs / Integrated Circuits • SKU RFB00522

$5.95

Texas Instruments SN7406N TTL hex inverter buffer/driver integrated circuit in a 14-pin DIP package, additionally marked with Hewlett-Packard house part number 1820-0471. Hewlett-Packard service documentation identifies 1820-0471 as an SN7406N TTL hex inverter device manufactured by Texas Instruments.

The SN7406N contains six independent inverting buffer/driver stages with high-voltage open-collector outputs. It operates from a 4.75V to 5.25V TTL supply and provides output sink capability up to 40 mA. Its open-collector architecture allows external pull-up circuitry and makes the device useful for interfacing standard TTL logic with indicator lamps, relays, peripheral circuitry, control signals, and other loads requiring greater output flexibility than a conventional TTL gate.

This is a general-purpose logic IC with applications extending well beyond arcade equipment. The SN7406 family has been used in computers, computer peripherals, industrial controls, instrumentation, test equipment, communications equipment, printers, relay interfaces, lamp drivers, digital control systems, and other TTL-based electronic assemblies.

The exact Texas Instruments SN7406N is NOT obsolete. Texas Instruments continues to list the SN7406N 14-pin PDIP version as an active production component. The Hewlett-Packard 1820-0471 number, however, is a legacy HP equipment and inventory designation associated with older Hewlett-Packard electronic equipment.

HISTORICAL BACKGROUND:

The 7406 belongs to the classic 7400-series TTL family that became a fundamental building block of digital electronics during the 1970s and 1980s. Before highly integrated controllers absorbed many support functions, equipment designers used individual TTL devices for buffering, switching, decoding, signal conditioning, control, and interfacing. The 7406 was particularly useful because its open-collector outputs allowed TTL circuitry to control external loads and interface with circuitry beyond ordinary TTL output levels.

Hewlett-Packard used the SN7406N under its internal 1820-0471 part designation in professional electronic equipment, demonstrating the device's role in laboratory and instrumentation hardware as well as general digital systems.

The 7406 also has genuine documented arcade history. Bally Midway's Spy Hunter documentation specifies a 7406 at IC location 12F. Atari Asteroids specifies a Type 7406 at PCB location N9, while Atari Dig Dug specifies a Type 7406 at location 11K. These documented applications make the SN7406N useful repair stock for vintage arcade PCB restoration as well as for computers, industrial electronics, instrumentation, communications equipment, and other TTL-era hardware.

The device was not designed exclusively for arcade machines; its importance comes from the broad range of electronic systems that relied on this versatile TTL interface function.