ATSAMD21G17A-AU - 48MHz Cortex-M0+ MCU, 128KB Flash | Microchip
MPN: ATSAMD21G17A-AU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.28 | $5.28 |
| 10 | $4.85 | $48.50 |
| 100 | $4.21 | $421.00 |
| 500 | $3.74 | $1,870.00 |
| 1,000 | $3.3 | $3,300.00 |
ATSAMD21G17A-AU Overview
What is a Cortex-M0+ microcontroller? A microcontroller (MCU) is a single-chip computer that integrates a CPU core, memory, and programmable peripherals. The ARM Cortex-M0+ is the smallest, most energy-efficient core in the Cortex-M family, designed for low-cost, low-power embedded applications. Microcontrollers belong to the broader hierarchy of embedded processors -> microcontrollers -> ARM Cortex-M microcontrollers -> Cortex-M0+ family. The SAM D21 family adds Microchip's peripheral set, including SERCOM, Event System, and advanced PWM/timer blocks.
Key features include six SERCOM configurable serial interfaces (UART/SPI/I2C), a 12-bit 350ksps ADC with up to 14 channels, two analog comparators, a 10-bit 350ksps DAC, and up to 38 GPIO pins. The integrated Full-Speed USB 2.0 transceiver and Device Controller eliminate the need for an external PHY, and the Event System allows peripherals to communicate without CPU intervention, reducing active time and power consumption.
Architecturally, the SAM D21G uses a single-cycle hardware multiplier, single-cycle 32-bit I/O access via the AHB-APB bridge, and a low-power SleepWalking peripheral event system. Functional Safety (FuSa) support and built-in CRC-32 hardware enable IEC 60730 class B compliance for home appliance designs, while a True Random Number Generator (TRNG) supports secure key storage in IoT nodes.
Typical applications include home automation gateways, smart metering, industrial sensor nodes, consumer wearables, USB HID peripherals, and low-power IoT edge devices. The wide 1.62V-3.6V supply range simplifies designs powered directly from single-cell Li-ion or 3.3V system rails.
Design consideration: at 48MHz the core reaches 2.46 CoreMark/MHz but can drop to under 100uA/MHz in standby with RTC running. Decoupling must include 100nF on each VDD pin and a 4.7uF bulk capacitor near the VCORE pin.
This page consolidates distributor pricing, drop-in pin-compatible alternatives, and practical design notes that go beyond the datasheet's parameter tables.
Drop-in alternatives for ATSAMD21G17A-AU — 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 ATSAMD21G17A-AU (same form factor and footprint) — differing in Operating Temperature, ADC, RoHS Status, DAC, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21G18A-AU
✅ Drop-In✓ In Stock
$1.74 / Unit
View Datasheet →ATSAMD21G17A-AUT
✅ Drop-In✓ In Stock
$3.41 / Unit
View Datasheet →ATSAMD21G17A-AFT
✅ Drop-In✓ In Stock
$3.7 / Unit
View Datasheet →ATSAMD21G17A-AU Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ (32-bit) |
| Series | SAM D21G, Functional Safety (FuSa) |
| Maximum Clock Frequency | 48 MHz |
| Performance | 2.46 CoreMark/MHz |
| Flash Memory | 128 KB |
| SRAM | 16 KB |
| RWW Flash Region | 4 KB |
| Supply Voltage (Vcc/Vdd) | 1.62 V to 3.6 V |
| GPIO Count | 38 |
| ADC | 12-bit, up to 350 ksps |
| DAC | 10-bit, 350 ksps |
| Analog Comparators | 2 |
| USB | Full-Speed USB 2.0 Device, integrated transceiver |
| SERCOM | 6 configurable (UART/SPI/I2C) |
| Package | 48-TQFP (7x7 mm) |
| Operating Temperature | -40 C to +85 C (industrial) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (Green) |
ATSAMD21G17A-AU Pin Configuration
| Pin 1 | PA00 — GPIO / XIN32 (external 32.768 kHz crystal input) |
| Pin 2 | PA01 — GPIO / XOUT32 (external 32.768 kHz crystal output) |
| Pin 3 | PA02 — GPIO / AIN0 (analog input) |
| Pin 4 | PA03 — GPIO / AIN1 / VREFA |
| Pin 5 | GND — Ground |
| Pin 6 | VDD — Digital supply voltage (1.62-3.6 V) |
| Pin 7 | PA04 — GPIO / AIN2 |
| Pin 8 | PA05 — GPIO / AIN3 |
| Pin 9 | PA06 — GPIO / AIN4 |
| Pin 10 | PA07 — GPIO / AIN5 |
| Pin 11 | PA08 — GPIO / AIN6 / VREFB |
| Pin 12 | PA09 — GPIO / AIN7 |
| Pin 13 | PA10 — GPIO / AIN8 |
| Pin 14 | PA11 — GPIO / AIN9 |
| Pin 15 | VDDIO — I/O supply voltage (1.62-3.6 V) |
| Pin 16 | GND — Ground |
| Pin 17 | PA12 — GPIO |
| Pin 18 | PA13 — GPIO |
| Pin 19 | PA14 — GPIO |
| Pin 20 | PA15 — GPIO |
| Pin 21 | PA16 — GPIO / SERCOM1 PAD0 |
| Pin 22 | PA17 — GPIO / SERCOM1 PAD1 |
| Pin 23 | PA18 — GPIO / SERCOM1 PAD2 |
| Pin 24 | PA19 — GPIO / SERCOM1 PAD3 |
| Pin 25 | PA20 — GPIO / SERCOM3 PAD2 |
| Pin 26 | PA21 — GPIO / SERCOM3 PAD3 |
| Pin 27 | PA22 — GPIO / SERCOM3 PAD0 |
| Pin 28 | PA23 — GPIO / SERCOM3 PAD1 |
| Pin 29 | PA24 — GPIO / USB_DM |
| Pin 30 | PA25 — GPIO / USB_DP |
| Pin 31 | GND — Ground |
| Pin 32 | VDD — Digital supply voltage |
| Pin 33 | PA26 — GPIO |
| Pin 34 | PA27 — GPIO |
| Pin 35 | PA28 — GPIO |
| Pin 36 | PA29 — GPIO |
| Pin 37 | PA30 — GPIO / SERCOM1 PAD2 (alt) |
| Pin 38 | PA31 — GPIO / SERCOM1 PAD3 (alt) |
| Pin 39 | PB00 — GPIO |
| Pin 40 | PB01 — GPIO |
| Pin 41 | PB02 — GPIO / SERCOM5 PAD0 |
| Pin 42 | PB03 — GPIO / SERCOM5 PAD1 |
| Pin 43 | PB04 — GPIO / SERCOM5 PAD2 |
| Pin 44 | PB05 — GPIO / SERCOM5 PAD3 |
| Pin 45 | PB06 — GPIO |
| Pin 46 | PB07 — GPIO |
| Pin 47 | PB08 — GPIO |
| Pin 48 | PB09 — GPIO / SWDIO (debug) |
Typical Applications
ATSAMD21G17A-AU is suitable for 6 applications: USB HID Peripherals (Keyboards, Mice, Custom Input), Home Automation and Smart Metering Gateways, Industrial Sensor Nodes and IoT Edge Devices, Consumer Wearables and Fitness Trackers, Battery-Powered Data Loggers, Educational and Maker Development Platforms.
USB HID Peripherals (Keyboards, Mice, Custom Input)
The ATSAMD21G17A-AU fits USB Human Interface Device designs thanks to its integrated Full-Speed USB 2.0 device controller with on-chip transceiver. At 48 MHz Cortex-M0+ with 128 KB Flash, the device can run HID class drivers, USB-CDC stacks, and composite-device descriptors without external PHY components, saving $0.30-0.50 BOM cost. The 38 GPIO count gives ample pins for matrix-scanned keyboards (typically 8x16 = 24 GPIO for a full keyboard), encoder inputs, and RGB LED PWM channels. Power consumption is approximately 7 mA active at 48 MHz with USB active, allowing bus-powered designs that meet USB suspend requirements (< 2.5 mA). Placed directly on the USB DP/DM pins with 22 ohm series termination and ESD protection array, this MCU removes the need for an external 3.3 V LDO for the USB bus.
Recommended
Home Automation and Smart Metering Gateways
The ATSAMD21G17A-AU suits home automation and metering gateway nodes because of its 1.62-3.6 V wide supply range, six SERCOM interfaces, and Cortex-M0+ 2.46 CoreMark/MHz efficiency. Three SERCOM channels can run concurrent UART, SPI, and I2C buses to a Wi-Fi/BLE module, a display, and a sensor front-end, while the remaining three SERCOMs service the metrology ASIC. The Event System triggers ADC sampling from timer output compare without CPU wakeup, lowering average current below 100 uA in SleepWalking mode. The 16 KB SRAM holds a TLS connection buffer for MQTT-over-TLS to the cloud, and the 4 KB RWW Flash enables secure OTA firmware updates without external EEPROM.
Recommended
Industrial Sensor Nodes and IoT Edge Devices
The ATSAMD21G17A-AU is well-suited to industrial 4-20 mA loop-powered sensor nodes and IoT edge devices because its 1.62 V minimum supply allows operation directly from 3.3 V regulated rails or low-dropout battery stacks. The 12-bit 350 ksps ADC with up to 14 channels handles multi-sensor acquisition, while two analog comparators provide hardware threshold detection for alarm outputs without waking the CPU. Industrial temperature range (-40 to +85 C as industrial grade), CRC-32 hardware, and IEC 60730 class B Functional Safety support enable appliance and metering designs that require safety certification. The integrated True Random Number Generator (TRNG) supports secure key generation for AES-128 hardware encryption.
Recommended
Consumer Wearables and Fitness Trackers
The ATSAMD21G17A-AU fits consumer wearables because of its Cortex-M0+ low-power SleepWalking modes that drop active current to under 100 uA/MHz when peripherals service themselves via the Event System. The 38 GPIO count supports an OLED display SPI bus, an I2C heart-rate sensor, a PWM-driven vibration motor, and capacitive touch buttons through the integrated PTC (Peripheral Touch Controller). At 48 MHz it can refresh a 128x64 OLED at 60 Hz while still running BLE provisioning via a companion radio module over UART. The 7x7 mm TQFP footprint is small enough for wrist-strap PCBs and the 1.62-3.6 V range accepts direct Li-ion battery voltage without a boost converter.
Recommended
Battery-Powered Data Loggers
The ATSAMD21G17A-AU is ideal for battery-powered data loggers because of its 16 KB SRAM buffer for time-stamped sensor records and 128 KB Flash for storing compressed log archives. With RTC running in standby, the device draws approximately 1.5 uA at 3 V, enabling multi-year operation from a single CR2032 cell for periodic logging applications. The integrated 12-bit ADC and Event System allow scheduled sensor sampling every minute without CPU intervention. The 4 KB RWW Flash region supports field firmware updates for bug fixes in deployed loggers, eliminating field recalls. USB device capability provides a convenient wired data download path without a separate programming header.
Recommended
Educational and Maker Development Platforms
The ATSAMD21G17A-AU is popular for educational development boards and maker platforms (e.g., Arduino Zero-compatible designs) because of its broad toolchain support in Microchip Studio, Arduino IDE, and PlatformIO. The integrated USB device controller provides drag-and-drop programming via the bootloader without an external programmer, lowering the barrier for students. 128 KB Flash accommodates the Arduino core libraries plus user sketches, while 16 KB SRAM supports real-time signal processing exercises. The 6 SERCOM channels map cleanly to the standard Arduino header SPI/I2C/UART pinout. The 48 MHz Cortex-M0+ with 2.46 CoreMark/MHz gives headroom for introductory DSP and PID control tutorials.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21G17A-AU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21G18A-AU | ATSAMD21G17A-AUT | ATSAMD21G18A-MUT |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) - same | 48-TQFP (7x7 mm) - same | 48-QFN (7x7 mm) - different |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ |
| Max Clock Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Flash Memory | 128 KB | 256 KB | 128 KB | 256 KB |
| SRAM | 16 KB | 32 KB | 16 KB | 32 KB |
| GPIO Count | 38 | 38 | 38 | 38 |
| Supply Voltage | 1.62-3.6 V | 1.62-3.6 V | 1.62-3.6 V | 1.62-3.6 V |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
| USB | USB 2.0 Full-Speed Device | USB 2.0 Full-Speed Device | USB 2.0 Full-Speed Device | USB 2.0 Full-Speed Device |
Key Differentiators
- Integrated Full-Speed USB 2.0 Device with on-chip transceiver (vs ATSAMD21G17A-AUT)
- Functional Safety (FuSa) features for IEC 60730 class B compliance (vs ATSAMD21G18A-MUT (QFN package))
- Same-package upgrade path to 256 KB Flash without PCB change (vs ATSAMD21G18A-AU)
Design Notes
Decouple each VDD pin with a 100 nF ceramic capacitor placed within 1-2 mm of the package body, and add a single 4.7 uF bulk capacitor near the VCORE pin. According to the SAM D21 datasheet power-supply section, missing the 4.7 uF on VCORE causes the internal 1.2 V regulator to oscillate and can corrupt Flash programming operations. A 10 uF bulk on VDDIO is recommended if USB is used.
Place the 32.768 kHz crystal within 5 mm of the XIN32/XOUT32 pins (PA00/PA01) with short, symmetric traces and a guard ring tied to ground. Long crystal traces introduce stray capacitance that shifts the load oscillator frequency and degrades RTC accuracy from typical +/-20 ppm to +/-100 ppm. Keep digital signal traces away from the crystal area to avoid injecting noise into the low-level oscillator stage.
USB DP/DM traces must be 90 ohm differential impedance-matched with trace length matching to within 150 mil, and must include 22 ohm series termination resistors near the MCU pins. According to USB 2.0 specification, impedance mismatch causes signal reflections that fail USB-IF compliance testing, especially at the high-speed eye-diagram test. Place an ESD protection array (e.g., USBLC6-2SC6) within 3 mm of the USB connector.
Do not drive the RESET pin low during normal operation unless a genuine reset is required; floating RESET can cause spurious resets in noisy environments. Tie RESET to VDDIO through a 10 kohm pull-up and a 100 nF capacitor to ground for proper power-on-reset timing. Per the datasheet, the RESET pin has an internal pull-up but it is too weak for reliable operation in industrial EMI environments without an external pull-up.
Compliance Information
Green / RoHS compliant per Microchip product page (industrial grade). Not AEC-Q100 qualified; for automotive designs use ATSAMC20/ATSAME54 family with AEC-Q100 grade. REACH SVHC declaration available from Microchip.
