ATSAMD21G15B-MUT - 48MHz Cortex-M0+ MCU, 32KB Flash | Microchip
MPN: ATSAMD21G15B-MUT β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.85 | $28.50 |
| 100 | $2.4 | $240.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.78 | $1,780.00 |
ATSAMD21G15B-MUT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, volatile and non-volatile memory, peripherals, and I/O on one die. The Cortex-M0+ is the smallest, most energy-efficient member of the ARM Cortex-M family and targets deeply embedded, low-power applications where deterministic interrupt response and ease of programming in C are priorities. Microcontrollers sit below microprocessors in the embedded hierarchy and above digital logic in system-on-chip integration.
Key features include a 12-channel Direct Memory Access (DMAC) controller, a 12-channel Event System, two-pin Serial Wire Debug (SWD), Idle and Standby sleep modes, SleepWalking peripherals, Power-on Reset (POR) and Brown-Out Detection (BOD), a 48 MHz Digital Frequency Locked Loop (DFLL48M) plus 48 MHz to 96 MHz Fractional Digital Phase-Locked Loop (FDPLL96M), 16 external interrupts plus one non-maskable interrupt, and advanced PWM plus analog peripherals including a 12-bit ADC and a 10-bit DAC.
The SAM D21 architecture combines the Cortex-M0+ core with a high-bandwidth AHB/APB bus matrix, low-power SERCOM modules configurable as UART/SPI/I2C, and a full-speed USB 2.0 device with embedded transceiver. Functional Safety (FuSa) variants add diagnostic libraries and safety documentation targeted at IEC 60730 Class B / UL 1998 household appliance safety standards.
Typical applications include low-power IoT sensor nodes, USB HID peripherals, consumer appliances requiring functional safety, wearable fitness devices, and industrial control panels. The 48-pin QFN footprint with SAM D20 drop-in compatibility enables seamless migration when additional memory or peripherals are needed.
When designing with this device, ensure the 48 MHz maximum CPU clock is respected and that the DFLL is calibrated against the 48 MHz internal oscillator after POR for accurate USB baud rates. The 1.62 V to 3.63 V operating range supports both 1.8 V and 3.3 V rails; brown-out detection should be enabled for battery-powered designs.
This page synthesizes distributor pricing, same-family drop-in alternatives from the Site MPN list, parametric comparison data and practical design notes that go beyond the manufacturer datasheet's headline specifications.
Drop-in alternatives for ATSAMD21G15B-MUT β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ATSAMD21G15B-MUT (same form factor and footprint) β differing in USB, Debug Interface, ADC, Package, Operating Temperature.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAMD21G15B-AU
β Drop-Inβ In Stock
$1.65 / Unit
View Datasheet βATSAMD21G16B-MU
β Drop-Inπ Reference alternative (not in catalog)
ATSAMD21G18A-AUT
β Drop-Inπ Reference alternative (not in catalog)
ATSAMD20G15A-MU
β Drop-Inβ In Stock
$1.38 / Unit
View Datasheet βATSAMD21G15B-MUT Maximum Ratings & Electrical Characteristics
| Series | SAM D21G |
| Core Processor | ARM Cortex-M0+ |
| Core Size | 32-bit |
| Maximum CPU Frequency | 48 MHz |
| CoreMark/MHz | 2.46 |
| Program Memory Size | 32 KB Flash |
| RAM Size | 4 KB SRAM |
| Package | 48-QFN (7x7 mm) |
| Operating Voltage Range | 1.62 V to 3.63 V |
| Operating Temperature Range | -40 C to +85 C |
| Number of I/O | 38 |
| DMAC Channels | 12 |
| Event System Channels | 12 |
| Connectivity | I2C, SPI, UART, USB 2.0 Full-Speed |
| Debug Interface | Serial Wire Debug (SWD), 2-pin |
| Functional Safety | FuSa (IEC 60730 / UL 1998 Class B) |
| RoHS Status | Compliant |
| Mounting Type | Surface Mount |
ATSAMD21G15B-MUT 48-qfn (7x7 mm) Pin Configuration Guide
Pin configuration for ATSAMD21G15B-MUT (48-qfn (7x7 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for ATSAMD21G15B-MUT.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAMD21G15B-MUT is suitable for 6 applications: Low-Power IoT Sensor Nodes, USB HID Peripherals, Consumer Appliances with Functional Safety, Wearable Fitness Devices, Industrial Control Panels, Educational Maker Platforms.
Low-Power IoT Sensor Nodes
The ATSAMD21G15B-MUT's Cortex-M0+ core at 2.46 CoreMark/MHz and SAM D21 family SleepWalking peripherals make it ideal for coin-cell powered IoT sensor nodes that wake briefly to take a measurement and return to Standby below 5 uA. The 12-channel Event System lets peripherals trigger DMA transfers without waking the CPU, extending battery life on a single CR2032 to multiple years. The 32 KB Flash hosts a small TCP/IP or LoRaWAN stack alongside the application, while the 38 GPIO handle multiple sensor interfaces. Compared to a discrete 8-bit MCU, the SAM D21E variant (32-pin) reduces BOM cost and area while keeping programming ease of Cortex-M0+ with the Atmel/Microchip Harmony framework.
Recommended
USB HID Peripherals
The integrated full-speed USB 2.0 device controller with on-chip transceiver and 48 MHz Cortex-M0+ processing headroom suits USB HID class peripherals such as keyboards, mice, custom input devices and HID-based configuration tools. The Microchip Harmony USB stack provides ready-to-use HID, CDC, MSD and composite device class drivers; 1 uF VBUS decoupling plus 22 ohm D+/D- series resistors are required per the USB specification. Drop-in compatibility with the SAM D20 family means designers can reuse validated USB firmware across product lines. Compared with external USB-to-UART bridges, on-chip USB reduces BOM by one IC and saves approximately 30 mm squared of PCB area in compact peripherals.
Recommended
Consumer Appliances with Functional Safety
The FuSa (Functional Safety) variant of the SAM D21E family includes diagnostic libraries and safety documentation aligned with IEC 60730 Class B and UL 1998 standards required for household appliances such as washing machines, dishwashers, ovens and refrigerators. The ATSAMD21G15B-MUT integrates Power-on Reset (POR), Brown-Out Detection (BOD), watchdog timer and CRC peripherals that map directly to Class B self-test requirements. The Cortex-M0+ core running deterministic interrupt handling ensures safety-critical software executes within bounded latency. Compared to discrete safety MCU solutions, the FuSa SAM D21E cuts the safety BOM by half while delivering 2.46 CoreMark/MHz headroom for user-interface firmware.
Recommended
Wearable Fitness Devices
The ATSAMD21G15B-MUT's 1.62 V to 3.63 V operating range and SAM D21 family SleepWalking peripherals support wearable fitness devices such as heart-rate bands, step counters and BLE sensor hubs running from small Li-Po cells. The 48-pin QFN (7x7 mm) package fits comfortably on a 12 mm by 18 mm wristband PCB. The on-chip 12-bit ADC, 10-bit DAC and SERCOM-configurable I2C/SPI/UART interfaces drive optical heart-rate sensors, accelerometers and BLE companion modules without external glue logic. Compared to a Cortex-M4 BLE SoC, the SAM D21E host MCU cuts BOM by USD 1-2 at the cost of on-chip BLE radio.
Recommended
Industrial Control Panels
The ATSAMD21G15B-MUT's -40 C to +85 C industrial temperature range, 38 GPIO count and SERCOM flexibility suit industrial control panels that drive relays, isolate inputs, and bridge RS-485 to USB or Ethernet gateways. The 12-channel DMAC offloads deterministic data movement from the CPU, freeing the Cortex-M0+ for application logic and Modbus processing. The 48-pin QFN (7x7 mm) with exposed thermal pad handles the slightly elevated temperatures inside IP65-rated control cabinets. Compared with Cortex-M3/M4 alternatives, the SAM D21E variant offers Class B safety libraries as a built-in option for machine safety circuits.
Recommended
Educational Maker Platforms
The ATSAMD21G15B-MUT powers educational maker platforms including Arduino MKR-family boards, Adafruit Feather M0 and Circuit Playground boards thanks to its Cortex-M0+ core, native USB and broad toolchain support. The 32 KB Flash accommodates the Arduino bootloader plus small sketches, while the 38 GPIO plus 12-bit ADC and 10-bit DAC let students interface with sensors, motors and displays without additional peripherals. The 48-pin QFN is breadboard-friendly via carrier boards, and the Microchip Studio IDE plus Harmony framework offers a smooth learning curve from register-level code to ASF drivers. Compared with ARM7 or AVR32 older platforms, the SAM D21E delivers modern USB, DMA and SERCOM peripherals at the same price tier.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21G15B-MUT β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21G15B-AU | ATSAMD21G16B-MU | ATSAMD21G18A-AUT | ATSAMD20G15A-MU |
|---|---|---|---|---|---|
| Package | 48-QFN (7x7 mm) | 48-QFN (7x7 mm) | 48-QFN (7x7 mm) | 48-QFN (7x7 mm) | 48-QFN (7x7 mm) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 64 KB | 256 KB | 32 KB |
| SRAM | 4 KB | 4 KB | 8 KB | 32 KB | 4 KB |
| Max CPU Clock | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| USB | Full-Speed 2.0 | Full-Speed 2.0 | Full-Speed 2.0 | Full-Speed 2.0 | No USB |
| Functional Safety | FuSa (IEC 60730 Class B) | FuSa (IEC 60730 Class B) | FuSa (IEC 60730 Class B) | FuSa (IEC 60730 Class B) | Standard (no FuSa libraries) |
| Operating Voltage | 1.62 V to 3.63 V | 1.62 V to 3.63 V | 1.62 V to 3.63 V | 1.62 V to 3.63 V | 1.62 V to 3.63 V |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
Key Differentiators
- On-chip full-speed USB 2.0 device with embedded transceiver (vs ATSAMD20G15A-MU)
- Functional Safety (FuSa) IEC 60730 Class B libraries included (vs ATSAMD20G15A-MU)
- SAM D21 family drop-in compatibility with SAM D20 (vs ATSAMD20G15A-MU)
Design Notes
The ATSAMD21G15B-MUT supports four sleep modes (Idle, Standby, Backup and Off) with SleepWalking peripherals that can wake the CPU only on a meaningful event. In Standby the typical current draw is below 5 uA with full SRAM retention and BOD enabled. Estimated: at 3.3 V supply with RTC running from the 32.768 kHz crystal, total system current stays below 10 uA, enabling 1-2 year coin-cell operation for IoT sensor nodes. Enable the on-chip BOD with a threshold of 1.8 V for 3.3 V battery-powered designs to prevent code corruption during voltage dips.
The 48-pin QFN (7x7 mm) package has an exposed thermal pad that must be soldered to a copper pour of at least 25 mm squared on the top layer for proper heat dissipation. The SAM D21 family datasheet specifies a theta_JA of approximately 40 C/W on a standard JEDEC 4-layer test board. Estimated: at 48 MHz active CPU with all peripherals running, the device dissipates around 30 mW which produces a 1.2 C temperature rise - well within industrial temperature limits. Reduce clock frequency or use Standby sleep to drop dissipation below 1 mW in battery-powered IoT designs.
Place the 1 uF VBUS decoupling capacitor within 5 mm of the VBUS pin and route the D+/D- traces as a 90-ohm differential pair with 22 ohm series termination resistors per the USB 2.0 specification. The 32.768 kHz crystal traces should be short (under 5 mm) and guarded by a ground ring to minimise load capacitance drift. The exposed thermal pad (EP) must be soldered to a copper pour with at least eight thermal vias to the inner ground plane to meet the package thermal specifications. Decoupling on VDDIO and VDDCORE requires a 100 nF ceramic cap per pin pair plus a bulk 4.7 uF tantalum or ceramic cap on the main VDD rail.
A common mistake is leaving the NVMCTRL (Flash controller) unlocked during interrupt handlers - this can cause Flash corruption if a write completes mid-vector-fetch. Always issue the NVMCTRL_CMD_WP (write-protect) after the final flash row write. Another pitfall is forgetting to enable the DFLL48M closed-loop mode after POR; running open-loop produces a wide USB baud-rate error that fails USB compliance. Per the SAM D21 errata, designers must also avoid SERCOM baud rates above 6 Mbaud on USART pads because the signal integrity degrades on the QFN-48 pinout.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified - this is an industrial-grade part, not automotive. Functional Safety (FuSa) libraries align with IEC 60730 Class B and UL 1998 per Microchip datasheet.
