STMicroelectronics has launched the STM32L4 series of ultra-low-power MCUs for next-generation energy-conscious consumer, industrial, medical, and metering applications.The first two microcontrollers in the series, the STM32L476 and STM32L486 , feature the 80MHz ARM Cortex-M4 core with DSP and floating-point unit (FPU). With the added advantage of the ST ART Accelerator, which allows zero-wait execution from Flash, the devices achieve up to 100 DMIPS at just 100µA/MHz active power consumption. Up to 1MB of dual-bank Flash supports sophisticated applications and read-while-write capability in addition to 128KB of SRAM.
STM32L4 microcontrollers leverage ST’s low-power technologies, including dynamic voltage scaling to balance power consumption with processing demand, smart architecture with FlexPowerControl, and seven power-management modes with sub-mode options. These include Stop, Standby, and Shutdown with current as low as 30nA. ST’s Batch Acquisition Mode (BAM) allows efficient data exchange with communication peripherals while in low-power mode.
The STM32L4 benefits from a smart architecture and peripherals to maximize efficiency and performance while ensuring low power consumption. Digital peripherals include USB OTG full speed with a dedicated supply that allows customers to maintain USB communication even when the system is powered at 1.8V. There is also a Digital Filter for Sigma-Delta Modulators (DFSDM) peripheral for connecting external sigma-delta modulators or PDM (Pulse Density Modulation) microphones.
Analog peripherals include three 12-bit/5MSps ADCs featuring smart operation that allows sample acquisition at low speed drawing only few tens of μA to limit maximum current, or at maximum speed so as to return quickly to ultra-low-power mode. The ADCs can provide up to 16-bit resolution with hardware oversampling. There is also a voltage-reference buffer that provides a reference for ADCs, DACs, or for external components through the VREF+ pin. In addition there are two 12-bit DACs with sample and hold capability, which can operate during the MCU’s deep power-saving modes when overall current is reduced to a few hundred nA. Other analog peripherals include two ultra low-power comparators that draw as little as 300nA, as well as two op-amps with external or internal feedback routing and Programmable Gain Amplifier (PGA) capability.