20 MHz 8-bit controller for extended-temperature control loops
The Microchip PIC16F628A-E/SS is an 8-bit PIC® MCU in the 16F family, built around a 20MHz core with 3.5KB (2K x 14) Flash program memory, 224 x 8 bytes of RAM, and 128 x 8 bytes of EEPROM. It packs 16 I/O lines, a UART/USART for serial communication, and on-chip peripherals including Brown-out Detect/Reset, POR, PWM, and WDT. Housed in a 20-SSOP surface-mount package, it runs from a 3V to 5.5V supply and uses an internal oscillator, saving the external crystal on cost-sensitive BOMs.
What the 125°C rating buys you on the BOM
If your design lives in an engine bay, a solar inverter enclosure, or a factory floor panel that sees afternoon heat soak, the 'E' grade eliminates the need for active cooling or a temperature derating margin. The 125°C junction rating also means the MCU can sit next to a hot power MOSFET or regulator without a thermal gap — something a component engineer should verify against the total system power dissipation, but the headroom is there. For a procurement desk checking a BOM line, this part is the drop-in replacement for the commercial-grade version when the qualification report comes back with a higher ambient requirement.
Memory and peripheral fit for a control application
With 3.5KB Flash and 224 bytes of RAM, this MCU is sized for small control loops, sensor readout, and simple communication protocol handling — think a fan controller reading a thermistor and driving a PWM output, or a serial bridge between a UART sensor and a host. The 128-byte EEPROM stores calibration constants or configuration parameters without needing an external serial EEPROM, saving a component and a PCB via. The 16 I/O pins in a 20-pin package leave room for a few LEDs, a pushbutton, and a serial interface while still having pins for feedback and control signals. The internal oscillator frees up two I/O pins that would otherwise be tied to a crystal, which matters when you are counting pins on a cost-constrained board.
Lifecycle and sourcing — no last-time-buy pressure
The base product number PIC16F628 spans multiple temperature and package variants, so if the 20-SSOP footprint does not fit a future board spin, a TSSOP or PDIP sibling exists within the same family without a software port.