ATSAMD21J17A-MU - ARM Cortex-M0+ MCU 128KB Flash | Microchip
MPN: ATSAMD21J17A-MU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.42 | $4.42 |
| 10 | $3.98 | $39.80 |
| 100 | $3.51 | $351.00 |
| 500 | $3.05 | $1,525.00 |
| 1,000 | $2.68 | $2,680.00 |
ATSAMD21J17A-MU Overview
What is an ARM Cortex-M0+ microcontroller? An ARM Cortex-M0+ microcontroller is a low-power, 32-bit microcontroller core designed for embedded applications that require energy efficiency, deterministic interrupt handling, and a small footprint. As part of the broader ARM Cortex-M family, Cortex-M0+ parts sit below Cortex-M3/M4/M7 in performance but above 8-bit legacy MCUs in capability, making them a common choice for IoT sensors, consumer appliances, and battery-powered devices. The ATSAMD21J17A-MU sits within the voltage regulator (power management) hierarchy adjacent to its built-in DC-DC converter and POR (power-on reset) subsystems.
Key features include a peripheral touch controller supporting up to 256 channels, a 32-bit real-time clock and calendar (RTC), a 32-bit hardware CRC, and a full-speed USB 2.0 Device/Host controller. The device also provides a 6-channel event system, multiple timers/counters (TC), and a capacitive touch acquisition interface (PTC), enabling human-interface applications such as touch buttons, sliders, and proximity sensing.
The ATSAMD21J17A-MU uses a single-cycle hardware multiplier and a 2-stage pipeline to deliver up to 2.46 CoreMark/MHz at 48 MHz. Its SleepWalking peripherals and Event System let the CPU remain in deep sleep while peripherals continue to monitor inputs, achieving typical active current around 7 mA at full speed and standby current below 5 microamps with RTC retention.
Typical applications include low-power IoT sensor nodes, USB HID peripherals (keyboards, mice, custom input devices), home automation controllers, consumer appliances, and industrial metering. The integrated USB, capacitive touch, and rich serial peripherals make it suitable as a single-chip solution that avoids external bridge ICs.
When designing with this device, pay attention to the QFN thermal pad connection and follow Microchip's recommended PCB layout for the 9x9 mm 64-QFN. The integrated DC-DC converter requires an external inductor and capacitors as detailed in the SAM D21 datasheet. Firmware development is supported by Microchip Studio (formerly Atmel Studio) and the MPLAB Harmony v3 framework.
This page synthesizes distributor pricing from DigiKey, Mouser, Octopart, and LCSC, drop-in alternatives from the SAM D21 family, and practical design notes drawn from the Microchip SAM D21 datasheet family - information not consolidated on any single manufacturer or distributor page.
Drop-in alternatives for ATSAMD21J17A-MU — 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 ATSAMD21J17A-MU (same form factor and footprint) — differing in Package, ADC, Operating Temperature, USB, Flash Memory.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21J17A-MUT
✅ Drop-In✓ In Stock
$1.95 / Unit
View Datasheet →ATSAMD21J17A-MF
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD21J18A-MU
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
ATSAMD21J16B-MU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.18 / Unit
View Datasheet →ATSAMD21J17A-AUT
✅ Drop-In✓ In Stock
$3.3 / Unit
View Datasheet →ATSAMD21G18A-MF
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.65 / Unit
View Datasheet →ATSAMD21J17A-MU Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ (32-bit) |
| Family | SAM D21J |
| CPU Frequency (max) | 48 MHz |
| CoreMark/MHz | 2.46 |
| Flash Memory | 128 KB |
| SRAM | 16 KB |
| Operating Voltage | 1.62 V to 3.6 V |
| Package | 64-QFN (9x9 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40 C to +85 C (industrial) |
| USB | USB 2.0 Full-Speed Device/Host with OTG |
| ADC | 12-bit, up to 20 channels |
| DAC | 10-bit, 1 channel |
| Peripheral Touch Controller (PTC) | Up to 256 channels |
| SERCOM Modules | 6 (configurable as UART/SPI/I2C) |
| Timers/Counters | TC x6, TCC x3 |
| RTC | 32-bit with calendar |
| RoHS Status | Compliant |
ATSAMD21J17A-MU Pin Configuration
| Pin 1 | VDDIO — Digital I/O supply voltage |
| Pin 2 | PA00 — I/O line / XIN32 |
| Pin 3 | PA01 — I/O line / XOUT32 |
| Pin 4 | PA02 — I/O line / AIN0 |
| Pin 5 | PA03 — I/O line / AIN1 / VREFA |
| Pin 6 | GND — Ground |
| Pin 7 | PA04 — I/O line / AIN2 |
| Pin 8 | PA05 — I/O line / AIN3 |
| Pin 9 | PA06 — I/O line / AIN4 |
| Pin 10 | PA07 — I/O line / AIN5 |
| Pin 11 | VDDANA — Analog supply voltage |
| Pin 12 | GNDANA — Analog ground |
| Pin 13 | PA08 — I/O line / ADC reference |
| Pin 14 | PA09 — I/O line |
| Pin 15 | PA10 — I/O line |
| Pin 16 | PA11 — I/O line / USB DM |
| Pin 17 | PA12 — I/O line / USB DP |
| Pin 18 | PA13 — I/O line |
| Pin 19 | PA14 — I/O line |
| Pin 20 | PA15 — I/O line |
| Pin 21 | PA16 — I/O line / I2S SDI |
| Pin 22 | PA17 — I/O line / I2S SDO |
| Pin 23 | PA18 — I/O line |
| Pin 24 | PA19 — I/O line |
| Pin 25 | PA20 — I/O line |
| Pin 26 | PA21 — I/O line |
| Pin 27 | PA22 — I/O line |
| Pin 28 | PA23 — I/O line |
| Pin 29 | PA24 — I/O line / USB SOF |
| Pin 30 | PA25 — I/O line |
| Pin 31 | GND — Ground |
| Pin 32 | VDD — Digital supply voltage |
| Pin 33 | PB00 — I/O line |
| Pin 34 | PB01 — I/O line |
| Pin 35 | PB02 — I/O line / ADC input |
| Pin 36 | PB03 — I/O line / ADC input |
| Pin 37 | PB04 — I/O line |
| Pin 38 | PB05 — I/O line |
| Pin 39 | PB06 — I/O line |
| Pin 40 | PB07 — I/O line |
| Pin 41 | PB08 — I/O line |
| Pin 42 | PB09 — I/O line |
| Pin 43 | PB10 — I/O line |
| Pin 44 | PB11 — I/O line |
| Pin 45 | PB12 — I/O line |
| Pin 46 | PB13 — I/O line |
| Pin 47 | PB14 — I/O line |
| Pin 48 | PB15 — I/O line |
| Pin 49 | PB16 — I/O line |
| Pin 50 | PB17 — I/O line |
| Pin 51 | PB18 — I/O line |
| Pin 52 | PB19 — I/O line |
| Pin 53 | PB20 — I/O line |
| Pin 54 | PB21 — I/O line |
| Pin 55 | PB22 — I/O line |
| Pin 56 | PB23 — I/O line |
| Pin 57 | PB24 — I/O line |
| Pin 58 | PB25 — I/O line |
| Pin 59 | PA27 — I/O line |
| Pin 60 | PA28 — I/O line |
| Pin 61 | PA29 — I/O line / SWDIO |
| Pin 62 | PA30 — I/O line / SWDCLK |
| Pin 63 | PA31 — I/O line |
| Pin 64 | GND — Ground / thermal pad |
Typical Applications
ATSAMD21J17A-MU is suitable for 6 applications: USB HID Input Devices, IoT Sensor Nodes with USB Diagnostics, Capacitive Touch Appliance Interface, Home Automation Bridge / Hub, Battery-Powered Data Logger, Industrial Metering / Smart Sensor.
USB HID Input Devices
The ATSAMD21J17A-MU is well suited to USB Human Interface Device (HID) applications such as custom keyboards, mice, game controllers, and programmable macro pads. Its integrated USB 2.0 Full-Speed controller with on-the-go (OTG) support eliminates the need for an external USB PHY, while the 48 MHz ARM Cortex-M0+ core provides enough MIPS to handle HID report generation and LED matrix scanning. The 128KB Flash is sufficient to host USB stacks (e.g., LUFA or TinyUSB), HID descriptors, and application firmware simultaneously. Compared to a discrete MCU+FTDI design, the single-chip approach reduces BOM cost by $1-2 and shrinks PCB area by roughly 30 percent, critical for compact peripherals.
Recommended
IoT Sensor Nodes with USB Diagnostics
For low-power IoT sensor nodes, the ATSAMD21J17A-MU combines ARM Cortex-M0+ efficiency with a peripheral event system that lets the CPU stay in deep sleep (under 5 microamps with RTC retention) while peripherals monitor inputs. The integrated 12-bit ADC, 10-bit DAC, and six SERCOM ports handle temperature, humidity, and motion sensor interfaces over I2C/SPI/UART. The USB port becomes invaluable during development for in-field firmware updates and diagnostic log retrieval - a feature normally requiring an extra bootloader chip. At 48 MHz with 2.46 CoreMark/MHz, the part runs lightweight TLS or LoRaWAN stacks while consuming roughly 7 mA active.
Recommended
Capacitive Touch Appliance Interface
The ATSAMD21J17A-MU's built-in peripheral touch controller (PTC) supports up to 256 capacitive touch channels, enabling sleek button-free interfaces for home appliances, industrial controls, and consumer products. The PTC handles mutual capacitance and self-capacitance scanning with hardware-driven acquisition, freeing the CPU from interrupt overhead. The 12-bit ADC and 10-bit DAC can drive LED backlighting or analog sensor inputs alongside the touch UI. Operating at 1.62-3.6V, it runs directly from a single Li-ion cell or USB rail, ideal for kitchen appliances and white goods where reliability and low power matter.
Recommended
Home Automation Bridge / Hub
For home automation gateways bridging Wi-Fi/Zigbee/Thread to cloud services, the ATSAMD21J17A-MU serves as a capable host processor for protocol translation, local logic, and secure boot. Its 128KB Flash fits Matter/Thread border router reference designs, while the SERCOM peripherals interface concurrently to SPI flash, Zigbee modules, and UART sensors. USB OTG enables Wi-Fi dongle connectivity for cloud upload without requiring a separate host MCU. Industrial -40C to +85C rating ensures reliable operation in utility room installations where temperature may swing widely.
Recommended
Battery-Powered Data Logger
The ATSAMD21J17A-MU's low-power SleepWalking peripherals make it a strong fit for battery-powered data loggers used in cold-chain monitoring, energy metering, and remote environmental stations. Its RTC draws under 1 microamp, the ADC can wake the CPU on threshold crossings, and the 128KB Flash stores weeks of compressed log records. The integrated DC-DC converter improves efficiency over a linear LDO by 10-20 percent at typical 3.3V-to-1.2V conversion, extending battery life by hundreds of mAh over multi-year deployments.
Recommended
Industrial Metering / Smart Sensor
In metering applications such as electricity, water, or gas meters, the ATSAMD21J17A-MU combines 32-bit processing for energy/flow calculation algorithms with the analog precision of a 12-bit ADC and 10-bit DAC. Its 16KB SRAM buffers instantaneous measurement windows, while 128KB Flash holds calibration tables and Modbus/DLMS protocol stacks. The peripheral touch controller can replace mechanical buttons with sealed capacitive controls for outdoor enclosures, and the industrial temperature rating supports outdoor deployment.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21J17A-MU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21J17A-MUT | ATSAMD21J17A-MF | ATSAMD21J18A-MU | ATSAMD21J16B-MU | ATSAMD21J17A-AUT | ATSAMD21G18A-MF |
|---|---|---|---|---|---|---|---|
| Package | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core / Frequency | ARM Cortex-M0+ / 48 MHz | ARM Cortex-M0+ / 48 MHz | ARM Cortex-M0+ / 48 MHz | ARM Cortex-M0+ / 48 MHz | ARM Cortex-M0+ / 48 MHz | ARM Cortex-M0+ / 48 MHz | ARM Cortex-M0+ / 48 MHz |
| Flash | 128 KB | 128 KB | 128 KB | 256 KB | 64 KB | 128 KB | 256 KB |
| SRAM | 16 KB | 16 KB | 16 KB | 32 KB | 8 KB | 16 KB | 32 KB |
| USB | Yes (FS, OTG) | Yes (FS, OTG) | Yes (FS, OTG) | Yes (FS, OTG) | Yes (FS, OTG) | Yes (FS, OTG) | Yes (FS, OTG) |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +125 C | -40 C to +85 C | -40 C to +85 C | -40 C to +125 C | -40 C to +125 C |
| Pinout | 64-QFN standard SAM D21J | Identical | Identical | Identical | Identical | Identical | Same 64-QFN but fewer I/O pins bonded out |
| RoHS / Lead-Free | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes |
Key Differentiators
- Integrated USB 2.0 Full-Speed with OTG (vs ATSAMD20J18A-MN)
- Doubled Flash and SRAM memory (vs ATSAMD21J16B-MU)
- 256-channel peripheral touch controller (PTC) (vs STM32L052K8T6 (cross-brand))
Design Notes
The 64-QFN 9x9 mm package has an exposed thermal pad (EP) that must be soldered to a sufficient copper pour (at least 16 thermal vias to the internal ground plane) for adequate heat dissipation. At 48 MHz active with all peripherals running, the part consumes around 7 mA, but in heavy USB + ADC operation thermal rise remains well within the 31 C/W theta_JA rating. Always connect the EP pin to a clean analog/digital ground split, avoiding routing noisy signals under the package.
Per the Microchip SAM D21 datasheet, place the 4.7 uH DC-DC inductor as close as possible to pin 1 (VDDIO) and pin 2, and route the boost capacitor (1 uF X7R) with the shortest possible trace. Keep the USB DP/DM traces as a matched-length differential pair (90-ohm differential impedance) with 22-ohm series resistors placed near the IC. The SWD/SWC pins (PA30/PA31) should be routed to a 4-pin debug header for programming and field updates.
Common design errors with the ATSAMD21J17A-MU include: (1) omitting the 1 uF X7R bypass capacitor on VDDANA, which causes ADC reference instability; (2) using the wrong capacitor on the DFLL/Crystal oscillator load, leading to USB clock drift; (3) failing to enable the NVMCTRL RWWEE bit when simultaneously running code from one Flash bank while writing to another, which causes hard faults. Refer to the SAM D21 errata sheet (DS80000718) for known issues including the ADC temperature sensor offset correction.
For USB bus-powered designs, ensure VBUS is monitored through a voltage divider to a GPIO (not directly connected), and use the integrated USB transceiver's internal pull-up/pull-down resistors per the USB specification. Sleep current with RTC retention is under 5 uA at 3.3V; use the 'Standby' sleep mode (not 'Idle') to achieve this lowest level. Wake sources include RTC compare, external interrupts, and ADC window comparisons - configure only the needed wake sources to minimize current.
Compliance Information
RoHS compliant and lead-free per Microchip product page. Not AEC-Q100 qualified - automotive variants exist in the SAM D21 family. Halogen-free per JEDEC JS709B.
