SiLabs claims low power for ARM Cortex-M3 MCU

Called Precision32 SiM3L1xx, the MCUs are said to be able to run at 175µA/MHz in active mode, and under 250nA in sleep with the real-time clock (RTC) enabled at 3.6 V.

The top clock rate is 50MHz, and intended applications include smart metering, utility monitoring, home automation, wireless security, asset tracking and personal medical devices.

Dynamic voltage scaling adjusts the internal device voltage in response to changing conditions, and there is a integrated buck converter.

“Dedicated peripherals such as a data transfer manager, AES encryption block and run-time encoder accelerate the processing of RF protocol for wireless applications without CPU intervention, reducing system power,” said the firm. “Enhanced DMA can reduce protocol-related power, and RAM and register state retention enables 4µs wake-up time.”

Claimed to be another power-saving feature, the LCD controller has “a charge redistribution architecture”, said the firm.

The charge pump generates an input voltage for the device circuits in sleep mode, which is said to cut both analogue and digital sleep currents.

Also supported are a multi-alarm RTC for clocking and interrupts, a sleep-mode UART, and an integrated sensor interface that provides sensor stimulus and measurement while the MCU sleeps. “The autonomous sensor interface continues to count in sleep mode and can wake the MCU after a count overflow or when the count reaches a programmable threshold,” said SiLabs.

“Configuring the output voltage to the lowest acceptable setting of the other IC components connected to the MCU minimises overall power consumption.” added the firm. “This technique is especially useful in battery-powered applications such as smart meters where it can extend battery lifetime to 20 years.”

The Eclipse-based integrated development environment (IDE) estimates power consumption and provides figures and a pie chart of the total supply current and additive currents for enabled peripherals as they are configured.

It also provides power-saving tips when the cursor hovers over a configurable setting.

Production quantities are available now in QFN and TQFP packages down to 5.5×5.5mm with 32 to 256kbyte flash, and development boards are available.

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