Ultra-Low-Power Arm Cortex-M4 with FPU-Based Microcontroller (MCU) with 2MB Flash and 256KB SRAM

DARWIN Generation U MCUs Are Perfect for Engineers Who Are Serious About Power and Performance

Please check latest availability status for a specific part variant.


DARWIN is a new breed of low-power microcontrollers built to thrive in the rapidly evolving Internet of Things (IoT). They are smart, with the biggest memories in their class and a massively scalable memory architecture. They run forever, thanks to wearable-grade power technology. They are also tough enough to withstand the most advanced cyberattacks. DARWIN microcontrollers are designed to run any application imaginable—in places where you would not dream of sending other micro controllers.

Generation U microcontrollers are perfect for wearables and IoT applications that cannot afford to compromise power or performance. The MAX32620/MAX32621 feature an Arm® Cortex®-M4 with FPU CPU that delivers high-efficiency signal processing, ultra-low power consumption and ease of use.

Flexible power modes, an intelligent PMU, and dynamic clock and power gating optimize performance and power consumption for each application. Internal oscillators run at 96MHz for high-performance or 4MHz to maximize battery life in applications requiring always-on monitoring.

Multiple SPI, UART, I2C, 1-Wire® master, and USB interfaces are provided. The four-input, 10-bit ADC with selectable references can monitor external sensors.

All versions provide a hardware AES engine. The MAX32621 is provides a secure trust protection unit (TPU) with a modular arithmetic accelerator (MAA) for fast ECDSA, a hardware PRNG entropy generator, and a secure boot loader. The MAX32620L provides a reduced 1MB of flash memory.

This data sheet applies to revision C and later. Legacy mode operation provides compatibility with revision A.

MAX32620 User's Guide

Maxim Low Power ARM Micro Toolchain (Mac)

Maxim Low Power ARM Micro Toolchain (Windows)

Arm® Cortex®-M4F Microcontroller (MCU) with 2MB Flash and 256KB SRAM Arm® Cortex®-M4F Microcontroller (MCU) with 2MB Flash and 256KB SRAM Enlarge+

Key Features

  • High-Efficiency Microcontroller for Wearable Devices
    • Internal Oscillator Operates Up to 96MHz
    • Low Power 4MHz Option for Always-On Monitoring
    • 2MB/1MB Flash Memory
    • 256KB SRAM
    • 8KB Instruction Cache
    • 1.2V Core Supply Voltage
    • 1.8V to 3.3V I/O
    • Optional 3.3V ±5% USB Supply Voltage
    • Wide Operating Temperature: -30°C to +85°C
  • Power Management Maximizes Uptime for Battery Applications
    • 122µW/MHz Active Executing from Cache
    • 62µW/MHz Active Executing from Flash
    • Wake-Up to 96MHz Clock or 4MHz Clock
    • 1.06µW Low Power Mode (LP0) Mode with RTC
    • 2.67µW Ultra-Low Power Data Retention Sleep Mode (LP1) with Fast 5µs (typ) Wakeup on 96MHz
    • 28µW/MHz Low Power Mode (LP2) Current
  • Optimal Peripheral Mix Provides Platform Scalability
    • Three SPI Masters, One SPI Slave
    • Four UARTs
    • Up to Three I2C Masters, One I2C Slave
    • 1-Wire® Master
    • Up to 49 General-Purpose I/O Pins
    • SPI Execute in Place (SPIX) Engine for Memory Expansion with Minimal Footprint
    • Full-Speed USB 2.0 with Internal Transceiver
    • Sixteen Pulse Train Engines
    • Six 32-Bit or 12 16-Bit Timers
    • Three Watchdog Timers with Independent Sources
    • Four-Input, 10-Bit Sigma-Delta ADC Operating at 7.8 kS/s, 5.5V and 1.8V Tolerant Inputs
    • AES-128, -192, -256 Hardware Engine
    • RTC Calibration Output
    • JTAG 1149.1 Compatible with Serial Wire Debug
  • Secure Valuable IP and Data with Robust Internal Hardware Security (MAX32621 Only)
    • Trust Protection Unit (TPU) Provides ECDSA and Modular Arithmetic Acceleration Support
    • True Random Number Generator (TRNG)
    • Secure Boot Loader


  • Fitness Monitors
  • Portable Medical Devices
  • Sensor Hub
  • Sport Watches
  • Wearable Medical Patches

MAX32620-EVKIT: Evaluation Kit for MAX32620 and MAX32621
MAX32621-EVKIT: Evaluation Kit for MAX32620 and MAX32621
MAX35103EVKIT2: Evaluation Kit for the MAX35103/MAX32620
MAX32620FTHR: Evaluation Kit for the MAX32620/MAX77650/MAX17055
Product Reliability Reports: MAX32621.pdf 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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Related Resources

High Reliability, Ultra-Low Power Microcontroller Powered by Arm Cortex M4 Processor with FPU for Industrial and IoT

  • High-Efficiency Microcontroller for Low Power, High Reliability Devices
  • Flexible Clocking Schemes
  • Power Management Maximizes Uptime for Battery Applications

Type ID Title
User Guide 6245 Getting Started with Eclipse
User Guide 6242 MAX32620 User's Guide