48 MHz 8-bit PIC with USB — the BOM-fit tier
The Microchip PIC18F13K50-I/SO is an 8-bit PIC MCU from the PIC® XLP™ 18K family, clocked at 48 MHz with 8 KB Flash program memory and 512 bytes of RAM.
USB 2.0 on an 8-bit core — what it changes for the BOM
The USB peripheral is the main reason to pick this part over a simpler 8-bit PIC. It integrates the USB transceiver and SIE, so the BOM needs only a 48 MHz crystal (or the internal oscillator for full-speed operation) and a few passives — no external PHY or USB controller. The 48 MHz core clock is fast enough to service USB interrupt transfers without stalling the application loop, though the 512-byte RAM budget means the USB buffer and application data share tight quarters. For designs that stream data over USB while running sensor polling or display updates, the 8 KB Flash and 256-byte EEPROM (256 x 8) provide separate non-volatile storage for calibration constants or configuration that survives firmware updates.
For dual-sourcing planning, the PIC16LF1559-I/SS is a functional alternative in the same XLP low-power family, though it runs at 32 MHz and lacks USB — so the USB requirement locks you to the PIC18F13K50 or its larger-memory siblings.