ATSAMD21G16B-MUT - 48MHz Cortex-M0+ MCU 64KB | 48-QFN | Microchip
MPN: ATSAMD21G16B-MUT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.45 | $3.45 |
| 10 | $3.05 | $30.50 |
| 100 | $2.62 | $262.00 |
| 500 | $2.31 | $1,155.00 |
| 1,000 | $2.05 | $2,050.00 |
ATSAMD21G16B-MUT Overview
A microcontroller (MCU) is an integrated circuit that combines a CPU core, volatile and non-volatile memory, programmable I/O peripherals, and a clock system on a single die. MCUs form the lowest tier of embedded computing, sitting between discrete logic and full microprocessors. The SAM D21 family is Microchip's low-power Cortex-M0+ line, designed to give designers deterministic real-time behavior, ultra-low sleep currents, and pin-compatible migration across 32-, 48-, and 64-pin packages for hardware reuse.
Key features include a 32-bit Cortex-M0+ core with single-cycle hardware multiplier, Micro Trace Buffer for lightweight instruction trace, brown-out detection and power-on reset, and two-pin Serial Wire Debug. The SAM D21G includes a 12-bit ADC with up to 350 ksps sampling, a 10-bit DAC, up to six SERCOM modules configurable as UART/SPI/I2C, and a full-speed USB 2.0 device with embedded PHY. The device is drop-in compatible with earlier D20 peripherals in the same 48-pin QFN.
Technically, the ATSAMD21G16B-MUT is the 48-pin QFN variant of the SAM D21 series, which scales flash (32KB-256KB) and pin count across 32-, 48-, and 64-pin families. The 'B' suffix denotes the second-generation silicon revision; per Microchip application note AT04470, the L variant has a different pinout and is not drop-in compatible with A/B variants.
Typical applications include IoT sensor nodes, USB peripherals, low-power wearables, and human-machine interface (HMI) panels in industrial control. The wide 1.62V-3.63V supply, low-power sleep modes, and integrated USB make it well-suited to battery-powered or bus-powered designs. Designers should note that the 48-QFN package requires a thermal pad (EP) soldered to a ground copper pour to meet rated datasheet endurance.
Drop-in alternatives for ATSAMD21G16B-MUT — 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 ATSAMD21G16B-MUT (same form factor and footprint) — differing in RoHS Status, Debug Interface, Operating Temperature, USB, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21G16B-MFT
✅ Drop-In✓ In Stock
$1.96 / Unit
View Datasheet →ATSAMD21G15B-MUT
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →ATSAMD21G16B-MUT Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ (32-bit) |
| Family | SAM D21G |
| Silicon Revision | B (second-generation) |
| Maximum CPU Frequency | 48 MHz |
| CoreMark Score | 2.46 CoreMark/MHz |
| Program Flash | 64 KB (64K x 8) |
| SRAM | 8 KB |
| Supply Voltage (VDDIN) | 1.62 V to 3.63 V |
| Operating Temperature | -40C to +85C (industrial) |
| Package | 48-pin QFN (7x7 mm) with exposed pad |
| I/O Pins | 38 GPIO |
| ADC | 12-bit, up to 350 ksps |
| DAC | 10-bit |
| Communication | Up to 6 SERCOM (UART/SPI/I2C) |
| USB | Full-Speed USB 2.0 Device with embedded PHY |
| Debug Interface | Serial Wire Debug (SWD), Micro Trace Buffer |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
ATSAMD21G16B-MUT Pin Configuration
| Pin 1 | PA00 — GPIO / XIN (external clock input) |
| Pin 2 | PA01 — GPIO / XOUT (external clock output) |
| Pin 3 | PA02 — GPIO / AIN0 (ADC input) |
| Pin 4 | PA03 — GPIO / AIN1 / VREFA / DAC0 |
| Pin 5 | GND — Ground |
| Pin 6 | VDDANA — Analog supply voltage |
| Pin 7 | PB08 — GPIO |
| Pin 8 | PB09 — GPIO |
| Pin 9 | PA04 — GPIO / AIN2 |
| Pin 10 | PA05 — GPIO / AIN3 |
| Pin 11 | PA06 — GPIO / AIN4 |
| Pin 12 | PA07 — GPIO / AIN5 |
| Pin 13 | PA08 — GPIO / AIN6 |
| Pin 14 | PA09 — GPIO / AIN7 |
| Pin 15 | PA10 — GPIO / AIN8 |
| Pin 16 | PA11 — GPIO / AIN9 |
| Pin 17 | VDDIN — Digital supply voltage |
| Pin 18 | GND — Ground |
| Pin 19 | PB10 — GPIO |
| Pin 20 | PB11 — GPIO |
| Pin 21 | PB12 — GPIO |
| Pin 22 | PB13 — GPIO |
| Pin 23 | PB14 — GPIO |
| Pin 24 | PB15 — GPIO |
| Pin 25 | PA12 — GPIO |
| Pin 26 | PA13 — GPIO |
| Pin 27 | PA14 — GPIO |
| Pin 28 | PA15 — GPIO |
| Pin 29 | GND — Ground |
| Pin 30 | VDDIO — I/O supply voltage |
| Pin 31 | PA16 — GPIO |
| Pin 32 | PA17 — GPIO |
| Pin 33 | PA18 — GPIO |
| Pin 34 | PA19 — GPIO |
| Pin 35 | PA20 — GPIO |
| Pin 36 | PA21 — GPIO |
| Pin 37 | PA22 — GPIO / USB_DP |
| Pin 38 | PA23 — GPIO / USB_DM |
| Pin 39 | PA24 — GPIO / USB_SOF |
| Pin 40 | PA25 — GPIO / SWDIO |
| Pin 41 | RESET — Reset (active low) |
| Pin 42 | PA27 — GPIO / SWCLK |
| Pin 43 | GND — Ground |
| Pin 44 | VDDIN — Digital supply voltage |
| Pin 45 | PB00 — GPIO |
| Pin 46 | PB01 — GPIO |
| Pin 47 | PB02 — GPIO / AIN10 |
| Pin 48 | PB03 — GPIO / AIN11 |
Typical Applications
ATSAMD21G16B-MUT is suitable for 6 applications: USB Peripherals (HID, CDC, MIDI), Battery-Powered IoT Sensor Nodes, Industrial HMI Control Panels, Wearable Fitness Devices, Low-Cost Motor Control (BLDC, Stepper), Educational Development Boards (Arduino/CircuitPython).
USB Peripherals (HID, CDC, MIDI)
The ATSAMD21G16B-MUT is an excellent fit for USB peripherals because it integrates a full-speed USB 2.0 device controller with embedded PHY, eliminating the need for an external USB transceiver. With 64 KB Flash and 8 KB SRAM it supports USB HID, CDC virtual COM port, and MIDI Device Class implementations. Placed on the bus-powered rail with ESD diodes on DP/DM, it provides a compact single-chip USB solution. Unlike microcontrollers without USB, the SAMD21G16B handles USB protocol in hardware, freeing the Cortex-M0+ core for application logic. The 48-pin QFN provides enough GPIO for typical HID button/LED matrices.
Recommended
Battery-Powered IoT Sensor Nodes
The ATSAMD21G16B-MUT is well-suited for IoT sensor nodes because of its wide 1.62V-3.63V supply range, microamp-class sleep currents in BACKUP mode, and 12-bit ADC for direct sensor digitization. The 64 KB Flash accommodates typical LoRaWAN, BLE-through-SPI-coprocessor, or NB-IoT modem firmware. Compared to higher-frequency Cortex-M4 parts, the Cortex-M0+ core at 48 MHz delivers 2.46 CoreMark/MHz with lower active current, extending battery life. The 48-pin QFN enables compact wearables while supporting the 38 GPIO needed for multi-sensor boards.
Recommended
Industrial HMI Control Panels
The ATSAMD21G16B-MUT drives industrial HMI panels via its six SERCOM channels (UART/SPI/I2C configurable on demand) for display, keypad, and communication links. The 10-bit DAC generates analog reference voltages for analog front-ends, while the 12-bit ADC digitizes position feedback and sensor inputs. Placed at the heart of an HMI panel between the display driver IC and the backplane, it replaces discrete microcontrollers. Compared to ARM Cortex-M3 alternatives, the SAM D21G provides sufficient processing at lower cost and power. The -40C to +85C rating on the MUT variant covers most factory-floor installations.
Recommended
Wearable Fitness Devices
The ATSAMD21G16B-MUT powers wearable fitness devices thanks to its low-power sleep modes, 10-bit DAC for haptic feedback waveforms, and SERCOM channels for SPI displays and I2C biometric sensors (heart-rate, SpO2). With 8 KB SRAM it handles typical fitness firmware plus BLE-over-SPI link layer management. Compared to dedicated wearables MCUs, the SAMD21G16B provides a more capable Cortex-M0+ for richer UIs while staying in low-power budgets. The 48-pin QFN (7x7 mm) is small enough for wrist-form-factor designs and is widely supported by Arduino/CircuitPython for prototyping.
Recommended
Low-Cost Motor Control (BLDC, Stepper)
The ATSAMD21G16B-MUT drives low-cost BLDC and stepper motors by generating complementary PWM via its TCC (Timer/Counter for Control) peripherals with dead-time insertion and fault inputs. Six SERCOM channels handle encoder feedback (SPI or quadrature) and UART command interfaces. Compared to dedicated motor-control MCUs, the SAM D21G16B provides adequate torque-loop performance at a fraction of the cost, while the -40C to +85C rating covers most consumer/light-industrial installations. The 48-pin QFN's exposed pad also serves as the thermal dissipation path for the controller board.
Recommended
Educational Development Boards (Arduino/CircuitPython)
The ATSAMD21G16B-MUT is the microcontroller at the heart of the Arduino Zero and Adafruit Feather M0 boards, supported by the official Arduino SAMD core and CircuitPython runtime. With 64 KB Flash and 8 KB SRAM it comfortably hosts the Arduino bootloader plus user sketches, while the SWD interface allows low-level debugging. Compared to 8-bit Arduino AVR alternatives, the SAMD21G16B delivers 32-bit performance, native USB, and a modern peripheral set at a similar price point. The 48-pin QFN is the standard package exposed by virtually every Arduino-compatible SAMD21 board.
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Recommended Products Summary
Engineering reference data for ATSAMD21G16B-MUT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21G16B-MFT | ATSAMD21G15B-MUT | ATSAMD21G16B-AU | ATSAMD21E17A-MFT |
|---|---|---|---|---|---|
| Package | 48-pin QFN (7x7 mm) | 48-pin QFN (7x7 mm) - same package | 48-pin QFN (7x7 mm) - same package | 48-pin TQFP (7x7 mm) - different package | 32-pin QFN (5x5 mm) - different package |
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same |
| Flash | 64 KB | 64 KB | 32 KB (-50%) | 64 KB | 128 KB (+100%) |
| SRAM | 8 KB | 8 KB | 4 KB (-50%) | 8 KB | 16 KB (+100%) |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ |
| Max CPU Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Operating Temperature | -40C to +85C | -40C to +125C | -40C to +85C | -40C to +85C | -40C to +125C |
| USB | Full-Speed USB 2.0 Device | Full-Speed USB 2.0 Device | Full-Speed USB 2.0 Device | Full-Speed USB 2.0 Device | Full-Speed USB 2.0 Device |
| GPIO Count | 38 | 38 | 38 | 38 | 26 (-32%) |
Key Differentiators
- Integrated USB 2.0 Full-Speed with embedded PHY (vs ATSAMD20G18 (no USB))
- 48-pin QFN with 38 GPIO - more than typical 32-pin MCUs (vs ATSAMD21E18A (32-pin QFN))
- Drop-in pin compatibility with ATSAMD21G16B-MFT for higher temperature grade (vs ATSAMD21G16B-MFT)
Design Notes
The 48-pin QFN package has a large central exposed thermal pad (EP) that MUST be soldered to a PCB ground copper pour for electrical and thermal performance. Per the SAM D21 datasheet, an array of 0.3 mm thermal vias under the EP is required to meet the package's theta JA specification. Without proper EP soldering, the device may overheat at high CPU loads and GPIO switching. The EP should NOT be used as the only ground connection - multiple GND pins around the package perimeter must also be connected.
The ATSAMD21G16B-MUT has separate analog (VDDANA) and digital (VDDIN/VDDIO) supply rails that should be decoupled with 1uF + 100nF capacitors placed as close to each pin as possible. AREF requires its own 10nF decoupling if the internal voltage reference is used. USB applications need 1uF on VDDIN plus ferrite beads between VDDIN and VDDIO for noise isolation. Per Microchip SAM D21 datasheet 40001882A, all supplies must rise together within 20 ms during power-up to avoid latch-up.
Do NOT substitute ATSAMD21G16L parts for ATSAMD21G16B-MUT - the L variant has a different pinout and is not drop-in compatible per Microchip app note AT04470. Do not assume A and B silicon revisions differ in pinout - they share the same pinout but the B revision is the recommended new design choice. Do not exceed 3.63 V on VDDIN or 3.63 V on incorrect production configurations; the absolute maximum is 4.0 V per datasheet stress ratings. The 48-QFN's EP must be soldered; do not leave it floating.
Place the 32 kHz crystal as close as possible to XIN/XOUT (PA00/PA01) with short, symmetric traces to minimize load capacitance mismatch. The full-speed USB DP/DM traces (PA22/PA23) must be routed as a 90-ohm differential pair with no stubs and ground reference on the adjacent layer. SWD traces (SWDIO/SWCLK on PA25/PA27) should be kept under 10 cm to maintain signal integrity with low-cost debug probes.
Compliance Information
RoHS and REACH compliant per Microchip product page. Lead-free and halogen-free per Microchip packaging specifications. Not AEC-Q100 qualified as a stand-alone part - the MUT grade is -40C to +85C industrial, not automotive. For AEC-Q100 needs, use the ATSAMD21G16B-MFT variant (-40C to +125C).