The STMicroelectronics STM8S105C4T3 is an 8-bit MCU from the STM8S family, built around the STM8 core running at 16 MHz. On-chip peripherals include a 10-channel 10-bit ADC, PWM timers, a watchdog timer, brown-out detect, and power-on reset. This combination targets cost-sensitive control applications in automotive body electronics, industrial sensors, motor control, and white goods where 8-bit architecture is sufficient and the wide temperature range is non-negotiable.
16 MHz core and memory sizing for the BOM decision
The 16 MHz clock rate is the ceiling for instruction throughput on this 8-bit core. For a control loop running at a few kilohertz or a UART polling routine at 115200 baud, 16 MHz leaves plenty of margin. The 2 KB RAM and 1 KB EEPROM are the tight constraints: if your application needs a large lookup table or a data log buffer, you will hit the RAM ceiling quickly.
Temperature grade and supply voltage — the deployment envelope
This part is not just industrial; it is rated for under-hood and engine-bay environments where ambient temperatures hit 105°C and the junction climbs higher. The 5.5 V maximum allows direct connection to a 5 V logic system without a level shifter on the power pin, which simplifies the BOM for 5 V industrial sensors and automotive modules.
No need to stockpile or plan a migration yet. The ROHS3 compliance is confirmed.
Package and footprint — 48-LQFP with 38 usable I/O
The 38 I/O lines leave 10 pins tied to power, ground, and the oscillator — typical for a 48-pin LQFP. The surface-mount package is suitable for reflow assembly.