Bare ICs
Mostly classic DIP chips for breadboards — 74HC logic, MCP-series ADCs, DACs and expanders, optocouplers and timers. Know the bus and package before ordering; almost everything here is a bare chip.
74HC logic gates, MCP3008/MCP23017 ADCs and expanders, 24LC256 EEPROM, 4N25-series optocouplers and ULN2803A drivers — bare DIP chips with no breakout-board conveniences like pull-ups or level shifting.
- SPI vs I2C splits the Microchip peripherals: MCP3008/MCP3208 ADCs, MCP23S17 and MCP4921/MCP4822 DACs are SPI; MCP23017, MCP23008 and the 24LC256 EEPROM are I2C — same functions, different bus.
- Nexperia 74HC parts cover glue logic: 74HC165 parallel-in shift register for reading inputs, 74HC138 3-to-8 decoder, 74HC4511 seven-segment driver and 74HC273 octal flip-flop, all in DIP-16/20.
- Isolation and drive: 4N25–4N28 optocouplers separate grounds, the ULN2803A sinks 8 channels for relays and steppers, the MAX7219 multiplexes LED matrices and the MAX232 shifts RS-232 levels.
- ATmega328P PDIP-28 chips with Arduino bootloaders and other MCU bare dies make up a portion of the group — functional silicon, not tooling adapters.
