64 MHz Cortex-M0+ in a 20-pin TSSOP — the memory and peripheral budget
The STM32G031F4P3 is an entry-level member of the STM32G0 series, built around a 32-bit ARM Cortex-M0+ core clocked at 64 MHz. The 16 KB of on-chip flash and 8 KB of SRAM set the application envelope — enough for a single-loop control task, a sensor hub polling I²C and SPI peripherals, or a LIN-bus node in an automotive sub-system, but tight for a full RTOS with a heavy TCP/IP stack.
Peripheral set and connectivity — what the 18 I/O pins serve
The 18 general-purpose I/O pins multiplex onto the standard STM32G0 peripheral set: two I²C interfaces, two SPI ports, two UART/USARTs with LINbus and IrDA support, plus a SmartCard interface. The 17-channel 12-bit SAR ADC resolves 1 mV steps on a 3.3 V reference — enough for reading thermistors, potentiometers, or current-sense resistors without an external ADC. Built-in brown-out detect (BOD), power-on reset (POR), and a watchdog timer (WDT) reduce the external supervisor IC count. The DMA controller moves ADC results or serial data without CPU intervention, which matters when the 64 MHz core is servicing multiple peripheral interrupts. The oscillator block accepts both an external crystal and the internal RC oscillator — the internal RC is trimmed to ±1% accuracy across temperature, sufficient for UART baud-rate generation without an external resonator for most applications.
Lifecycle and sourcing — active, no NRND flag
No stock-holding claim — each order is quoted to the BOM line.
Package and board-fit — 20-TSSOP footprint checklist
The 20-TSSOP body is 4.40 mm wide with a 0.65 mm pin pitch. The recommended land pattern uses 0.30 mm pad width and 1.00 mm pad length, with a 4.40 mm pad row spacing. The package has no exposed thermal pad — the junction-to-ambient thermal resistance (RthJA) is dominated by the copper area on the top and bottom layers under the body. The supply decoupling should place a 100 nF capacitor within 5 mm of each VDD/VSS pair, with a 4.7 µF bulk capacitor near the MCU.