user
An STM32 with at least 128KB of Flash, easy soldering, few pins, low power consumption and 2 I²C interfaces
alphonsio

The STM32L412KB MCU may be the best choice

LQFP32 vs UFQFPN32

Here are STM32 microcontrollers that meet your requirements of:

  • At least 128KB of Flash
  • Easy to solder
  • Few pins
  • Low power consumption

In the STM32L family, the L stands for Low Power.

✅ Top Candidates

1. STM32L071KB

  • Flash: 128 KB
  • Package: LQFP32, UFQFPN32 → Easy to solder, few pins
  • Core: Arm Cortex-M0+ @ 32 MHz
  • RAM: 20 KB
  • Low Power: Yes (93 µA/MHz run current)
  • I²C interfaces: 2
  • Voltage: 1.65–3.6V
  • Temperature Range: –40°C to 125°C
  • Extras: Secure Boot, Software IP Protection
  • Great for: Battery-powered, cost-sensitive applications

2. STM32L412KB

  • Flash: 128 KB
  • Package: LQFP32, UFQFPN32
  • Core: Arm Cortex-M4 @ 80 MHz with FPU
  • RAM: 40 KB
  • Low Power: Yes (70 µA/MHz run current)
  • I²C interfaces: 2
  • Voltage: 1.71–3.6V
  • Extras: USB, Quad SPI, True RNG, Security features
  • Great for: Low-power applications that also need performance and USB support

3. STM32L422KB

  • Flash: 128 KB
  • Package: LQFP32, UFQFPN32
  • Core: Arm Cortex-M4 @ 80 MHz with FPU
  • RAM: 40 KB
  • Low Power: Yes (70 µA/MHz run current)
  • I²C interfaces: 2
  • Voltage: 1.71–3.6V
  • Extras: USB, Quad SPI, AES, TRNG, Advanced security features
  • Great for: Secure IoT devices and low-power connected applications

🏆 Best Overall Recommendation

STM32L412KB — offers the best balance of low power, performance (M4 + FPU), small package, 2 I²C interfaces and USB capability.

For prototyping, you can buy a Nucleo-32 development board with STM32L412KB MCU that supports Arduino nano connectivity:
Nucleo-32 development board with STM32L412KB MCU