The NuMicro® M2U51 / M2U54 ultra-low power series is based on Arm^® Cortex^®-M23 core at Armv8-M architecture with a single-cycle hardware multiplier/divider. It runs up to 40 MHz and features 32K to 256 Kbytes Flash Memory, 6K to 32 Kbytes SRAM, 1.75V to 5.5V operating voltage, and -40°C to +105°C wide operating temperature. Designed for energy-sensitive, battery-powered, and battery-less applications, the M2U51 offers flexible power modes that balance performance and power consumption across active, sensing, and long-standby workloads. It consumes 67.5 μA/MHz in Normal Run mode with the LDO and only 36 μA/MHz with the DC-DC converter. For low-power operation, it consumes less than 4 μA in Normal Power-down mode with the LCD charge pump fully operational and only 0.4 μA in Standby Power-down mode with RAM retention, helping extend battery life without compromising essential system functions. Auto Operation Mode further reduces power consumption by allowing low power peripherals and the PDMA controller to acquire and store sensor data while minimizing CPU intervention. This combination of flexible power management, ultra-low standby current, and auto operation mode delivers outstanding power-performance efficiency, demonstrated by the M2U51 / M2U54’s achievement in the ULPMark™-PP benchmark. These capabilities make the M2U51 / M2U54 well suited for fire security systems, industrial and smart-building devices, medical devices, smart meters, energy-harvesting systems, smart-home products, and IoT devices.

Ultra Low Power Technology

In addition to providing ultra-low current consumptions across multiple power modes, the M2U51 / M2U54 series offers Normal run mode with power consumption 67 μA/MHz in LDO mode and 36 μA/MHz in DC-DC mode, and equipped with different ultra-low-power modes. The current consumption of Normal Power-down mode with full with LCD charge pump operation is lower than 4 µA; with RAM retention consumes only 0.4 µA in Standby Power-down mode. The M2U51 / M2U54 series offers Auto-operation mechanism, which means to proceed the sensor data through low power serial interface with low power DMA without interrupting CPU.

Enhanced Analog Features

The M2U51 / M2U54 series is integrated with 8 x 42 segment LCD, providing one 16-ch 1 Msps 12-bit Low Power SAR ADC; multiple levels of internal voltage reference, two sets of rail-to-rail Low Power analog comparator, high precision temperature sensor, low voltage reset (LVR) and brown-out detector (BOD) to enhance product performance, reduce external components and form factor simultaneously.

Rich peripherals

The M2U51 / M2U54 series integrates a rich set of low-power peripherals designed to support Auto Operation Mode, allowing sensor data acquisition and processing without continuous CPU intervention. Through the internal bus matrix and PDMA engine, peripherals such as ADC, SPI, I²C, UART, and GPIO can automatically transfer data to SRAM while the CPU remains in low-power sleep mode, and wake up only when required through events such as data count match, timer/RTC triggers, or PDMA interrupts, effectively reducing system power consumption.

Supported packages include TSSOP 20-pin, TSSOP 28-pin, QFN 33-pin, QFN 48-pin, LQFP 64-pin, QFN 88-pin, and LQFP 128-pin. Package is Halogen-free, RoHS-compliant and TSCA-compliant.

For the development, Nuvoton provides the NuMaker evaluation board and Nuvoton Nu-Link-pro debugger. Recommended to use Nu-Link-Pro. The 3rd Party IDE such as Keil MDK, IAR EWARM, VS Code are also supported.

Target Application:

• Fire Security System
• Industrial and Smart Building Devices
• Medical Devices
• Smart Metering
• Energy Harvesting
• Smart Home
• IoT Device

Key Features:

•   96-bit Unique ID (UID)

•   128-bit Unique Customer ID (UCID)

•   IEC60730 Class B Compliance Safety Library

Development Environment:

Evaluation Board