ST has built a new architecture to reach best-in-class ultra-low-power figures thanks to its high flexibility. STM32L4 MCUs have scored 150 (world record) in the standardized EEMBC™ ULP Bench® tests that compare the efficiency of ultra-low-power microcontrollers. Moreover, the STM32L4 series shatters performance limits in the ultra-low-power world. It delivers 100 DMIPS based on its ARM® Cortex®-M4 core with FPU and ST ART Accelerator™ at 80 MHz.
Speaking to Electronics Maker, Mr. Vinay Thapliya, MCU Marketing and Technical Manager, STMicroelectronics India said, ‘’STM32L4 microcontrollers offer dynamic voltage scaling to balance power consumption with processing demand, low-power peripherals (LP UART, LP timers) available in Stop mode, safety and security features, smart and numerous peripherals, advanced and low-power analog peripherals such as op amps, comparators, LCD, 12-bit DACs and 16-bit ADCs (hardware oversampling).’’
In addition to the combination of low-power technologies, the STM32L4 also 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 isalso 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.
Speaking on the target segments, Mr. Thapliyal asserted that STM32L4 is most suited for wearable devices. For applications like fitness band, smart watchetc, STM32L4 offers TFT display interface, analog interface such as op amp, ADC and DAC, USB, audio interface. And to ensure wireless connectivity STM32L4 offers 4x SPI ports, USART, LIN, IrDA, modem and 1xSDIO. For ensuring security STM32L4 supports 128/256 bit AES key encryption hardware accelerator.
The STM32L4 smart architecture gives a further boost to performance and efficiency by enabling concurrent transfers between the core, DMA controllers, memories, and peripherals. Flex Power Control is another aspect of the smart architecture that assists power-saving design by retaining I/O levels when the device is in low-power mode, keeping SRAM in standby, and managing independent power supplies for specific peripherals and I/Os.
The STM32L486 integrates a hardware cryptographic co-processor (AES 256-bit). Combined with other STM32L4 features such as an independent battery-backup domain and tamper inputs, this provides a strong platform for security-oriented applications such as smart meters.
For applications where heat dissipation is a challenge, such as when used in confined environments or high ambient temperatures, high-temperature grade devices specified up to 125°C are available.
