ATSAMD21J17D-AU - 128KB Flash Cortex-M0+ MCU | Microchip
MPN: ATSAMD21J17D-AU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.5668 | $4.57 |
| 10 | $3.5525 | $35.53 |
| 25 | $2.4447 | $61.12 |
| 100 | $2.7057 | $270.57 |
| 250 | $2.2272 | $556.80 |
ATSAMD21J17D-AU Overview
An ARM Cortex-M0+ microcontroller is a low-power 32-bit processor core designed by ARM Holdings specifically for embedded applications that require deterministic performance at very low energy budgets. The Cortex-M0+ architecture is positioned within the broader microcontroller taxonomy as a streamlined descendant of the Cortex-M3/M4 family, optimized for cost-sensitive and energy-constrained designs while retaining full Thumb-2 instruction set compatibility. Within the SAM D family, this part occupies the mid-density tier with substantial Flash and SRAM for connected and sensor-rich applications.
Key features include a 32-bit Cortex-M0+ core with single-cycle multiplier, Full-Speed USB Device/Host with on-chip transceiver, 12-bit 1 MSPS ADC with up to 20 channels, two 12-bit DAC outputs, six SERCOM serial communication interfaces configurable as UART/SPI/I2C, six 24-bit timer/counters, and a Peripheral Touch Controller (PTC) supporting up to 256 buttons. The integrated Event System enables deterministic inter-peripheral signaling without CPU intervention, while the SERCOM multiplexer allows flexible pin-mapping. Operating voltage spans 1.62V to 3.6V with multiple low-power sleep modes down to sub-microamp current levels.
Typical applications include USB HID peripherals, low-power wireless sensor nodes, home automation controllers, smart metering endpoints, industrial sensor hubs, consumer wearables, and battery-powered IoT edge devices. The integrated USB PHY eliminates the need for external transceivers, reducing BOM cost and PCB area for Human Interface Devices such as keyboards, mice, and game controllers.
When designing with this MCU, ensure the 32 kHz crystal load capacitor values match the crystal manufacturer's specification to maintain RTC accuracy. For USB applications, the D+ line requires an external pull-up resistor to VBUS through a soft-connect capable GPIO to support hot-plug and remote wake-up scenarios.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, application reference designs, and practical design notes beyond the manufacturer datasheet.
Drop-in alternatives for ATSAMD21J17D-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 ATSAMD21J17D-AU (same form factor and footprint) — differing in DAC, ADC, Flash Memory, Core, USB.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21J17D-AUT
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →ATSAMD21J18A-AU
✅ Drop-In✓ In Stock
$2.69 / Unit
View Datasheet →ATSAMD20J17A-AU
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →ATSAMD21J17D-AU Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ (32-bit) |
| Maximum CPU Clock | 48 MHz |
| Flash Memory | 128 KB |
| SRAM | 16 KB |
| RWW EEPROM Emulation | 4 KB |
| Operating Voltage Range | 1.62 V to 3.6 V |
| Operating Temperature Range | -40 C to +85 C (Industrial) |
| Package | 64-pin TQFP |
| ADC | 12-bit, up to 20 channels, 1 MSPS |
| DAC | 10-bit, 2 channels |
| USB Interface | USB 2.0 Full-Speed Device/Host with on-chip transceiver |
| SERCOM Channels | 6 (configurable UART/SPI/I2C) |
| Timer/Counters | 6 x 24-bit |
| Peripheral Touch Controller | Yes, supports up to 256 buttons |
| GPIO Count (approx) | 52 (varies by package) |
| Mounting Type | Surface Mount |
| Lead-Free / RoHS | Yes (Green, compliant) |
ATSAMD21J17D-AU Pin Configuration
| Pin 1 | PA00 — General-purpose I/O / XIN32 (32.768 kHz crystal input) |
| Pin 2 | PA01 — General-purpose I/O / XOUT32 (32.768 kHz crystal output) |
| Pin 3 | PA02 — General-purpose I/O / AIN0 (ADC input) |
| Pin 4 | PA03 — General-purpose I/O / AIN1 (ADC input) / VREFA reference voltage |
| Pin 5 | VDDIO — Digital I/O supply voltage |
| Pin 6 | GND — Ground |
| Pin 7 | PA04 — General-purpose I/O / AIN2 (ADC input) |
| Pin 8 | PA05 — General-purpose I/O / AIN3 (ADC input) |
| Pin 9 | PA06 — General-purpose I/O / AIN4 (ADC input) |
| Pin 10 | PA07 — General-purpose I/O / AIN5 (ADC input) |
| Pin 11 | PA08 — General-purpose I/O / AIN6 (ADC input) |
| Pin 12 | PA09 — General-purpose I/O / AIN7 (ADC input) |
| Pin 13 | PA10 — General-purpose I/O / AIN8 (ADC input) |
| Pin 14 | PA11 — General-purpose I/O / AIN9 (ADC input) |
| Pin 15 | VDDANA — Analog supply voltage |
| Pin 16 | GND — Ground |
| Pin 17 | PA12 — General-purpose I/O / AIN10 / SERCOM |
| Pin 18 | PA13 — General-purpose I/O / AIN11 / SERCOM |
| Pin 19 | PA14 — General-purpose I/O / AIN12 / SERCOM |
| Pin 20 | PA15 — General-purpose I/O / AIN13 / SERCOM |
| Pin 21 | PA16 — General-purpose I/O / AIN14 / SERCOM |
| Pin 22 | PA17 — General-purpose I/O / AIN15 / SERCOM |
| Pin 23 | PA18 — General-purpose I/O / SERCOM |
| Pin 24 | PA19 — General-purpose I/O / SERCOM |
| Pin 25 | PA20 — General-purpose I/O / SERCOM |
| Pin 26 | PA21 — General-purpose I/O / SERCOM |
| Pin 27 | PA22 — General-purpose I/O / SERCOM |
| Pin 28 | PA23 — General-purpose I/O / SERCOM / USB_DM |
| Pin 29 | PA24 — General-purpose I/O / SERCOM / USB_DP |
| Pin 30 | PA25 — General-purpose I/O / SERCOM |
| Pin 31 | PA26 — General-purpose I/O |
| Pin 32 | PA27 — General-purpose I/O |
| Pin 33 | PA28 — General-purpose I/O / RESET (alternate function) |
| Pin 34 | VDDCORE — Internal core voltage regulator output (decoupling) |
| Pin 35 | GND — Ground |
| Pin 36 | PA30 — General-purpose I/O / SWDIO (programming/debug) |
| Pin 37 | PA31 — General-purpose I/O / SWCLK (programming/debug) |
| Pin 38 | PB00 — General-purpose I/O / SERCOM |
| Pin 39 | PB01 — General-purpose I/O / SERCOM |
| Pin 40 | PB02 — General-purpose I/O / SERCOM / AIN14 alt |
| Pin 41 | PB03 — General-purpose I/O / SERCOM / AIN15 alt |
| Pin 42 | PB04 — General-purpose I/O / SERCOM |
| Pin 43 | PB05 — General-purpose I/O / SERCOM |
| Pin 44 | PB06 — General-purpose I/O / SERCOM |
| Pin 45 | PB07 — General-purpose I/O / SERCOM |
| Pin 46 | PB08 — General-purpose I/O / SERCOM |
| Pin 47 | PB09 — General-purpose I/O / SERCOM |
| Pin 48 | PB10 — General-purpose I/O / SERCOM |
| Pin 49 | PB11 — General-purpose I/O / SERCOM |
| Pin 50 | PB12 — General-purpose I/O / SERCOM |
| Pin 51 | PB13 — General-purpose I/O / SERCOM |
| Pin 52 | PB14 — General-purpose I/O / SERCOM |
| Pin 53 | PB15 — General-purpose I/O / SERCOM |
| Pin 54 | PB16 — General-purpose I/O / SERCOM |
| Pin 55 | PB17 — General-purpose I/O / SERCOM |
| Pin 56 | PB22 — General-purpose I/O / SERCOM |
| Pin 57 | PB23 — General-purpose I/O / SERCOM |
| Pin 58 | PB30 — General-purpose I/O |
| Pin 59 | PB31 — General-purpose I/O |
| Pin 60 | VDDIO — Digital I/O supply voltage |
| Pin 61 | GND — Ground |
| Pin 62 | XIN — External crystal/clock input (main oscillator) |
| Pin 63 | XOUT — External crystal output (main oscillator) |
| Pin 64 | RESET — Reset input (active low) |
Typical Applications
ATSAMD21J17D-AU is suitable for 7 applications: USB HID Peripherals, Home Automation Controllers, Smart Metering Endpoints, Wearable Fitness Devices, Industrial Sensor Hubs, Capacitive Touch Keyboards, Battery-Powered IoT Sensor Nodes.
USB HID Peripherals
The ATSAMD21J17D-AU is ideal for USB Human Interface Devices such as keyboards, mice, game controllers, and custom HID peripherals. Its integrated USB 2.0 Full-Speed transceiver with on-chip 3.3V regulator eliminates external PHY and LDO components, reducing BOM cost by approximately 30 cents per board. The 48 MHz Cortex-M0+ core is more than sufficient for HID class driver execution at the 1 ms USB Full-Speed polling interval, leaving cycles for LED matrix scanning, key debouncing, or wireless link management. Soft-connect support via GPIO allows remote wake-up and hot-plug detection. The 128 KB Flash fits USB HID bootloaders plus application firmware for high-end keyboards with macro layers and RGB lighting control.
Recommended
Home Automation Controllers
The ATSAMD21J17D-AU serves as the main controller in home automation hubs for Zigbee, BLE, or Wi-Fi mesh bridges. Six SERCOM channels can simultaneously drive UART-linked radios, SPI flash memory, I2C sensors, and a UART debug console. The 12-bit 1 MSPS ADC supports analog sensor inputs (light, temperature, humidity) and the 10-bit DAC provides reference voltage outputs for analog front ends. With sub-microamp standby current and RTC wake capability from a 32 kHz crystal, the device minimizes idle power between sensor polls. The 64-pin TQFP package is well-suited for hand-solderable prototypes and small production runs.
Recommended
Smart Metering Endpoints
The ATSAMD21J17D-AU is well-suited for electricity, water, and gas metering endpoints requiring reliable data logging and 10+ year battery life. Its 12-bit ADC with 20 channels reads multiple analog sensor bridges simultaneously while the Cortex-M0+ core performs power-quality analysis at 48 MHz. RWW EEPROM emulation (4 KB) stores tariff tables and calibration constants without wear on main Flash. Low-power STANDBY mode drawing under 5 uA allows the meter to sleep between ADC samples, extending battery life significantly. Hardware AES in the SAML21 line is not present here, but external SPI secure elements can be added via SERCOM for authentication.
Recommended
Wearable Fitness Devices
Wearable fitness bands and health-monitoring patches benefit from the ATSAMD21J17D-AU's tiny power budget and rich analog peripherals. The integrated 12-bit ADC reads heart-rate photoplethysmography (PPG) sensor outputs while a second ADC channel reads temperature. The 10-bit DAC drives the PPG LED bias with software-controlled intensity, eliminating an external DAC. Multiple SERCOM channels connect to BLE modules, SPI displays, and I2C accelerometers concurrently. Deep sleep currents under 5 uA at 1.8V allow multi-day operation from a single coin-cell when the device is in standby between measurements.
Recommended
Industrial Sensor Hubs
Industrial 4-20 mA loop-powered sensor hubs use the ATSAMD21J17D-AU as the digital core, with its 1.62-3.6V supply matching typical sensor rails. The 12-bit ADC with differential input mode reads bridge pressure sensors and RTD outputs directly, while the DAC generates excitation voltage for resistive bridges. Hardware averaging and oversampling in the ADC achieve effective 14-bit resolution for precision measurements. Multiple SERCOM ports drive RS-485 transceivers, SPI FRAM, and I2C EEPROM for data buffering. The -40C to +85C industrial temperature range ensures operation in factory floor environments without additional thermal management.
Recommended
Capacitive Touch Keyboards
The ATSAMD21J17D-AU integrates the Peripheral Touch Controller (PTC) which supports up to 256 capacitive touch buttons, sliders, and wheels without external touch ICs. The PTC supports both mutual-capacitance and self-capacitance sensing with hardware-driven acquisition, freeing the Cortex-M0+ core for backlight control, USB HID reporting, and LED animation. Driven shield capability reduces moisture interference for kitchen-appliance and outdoor applications. Combined with the 48 MHz core and 128 KB Flash, designers can implement full QWERTY keyboards with multi-touch gestures, haptic feedback, and BLE wireless output from a single MCU.
Recommended
Battery-Powered IoT Sensor Nodes
Battery-powered IoT sensor nodes in remote deployments leverage the ATSAMD21J17D-AU for years of unattended operation. Multiple low-power sleep modes (IDLE, STANDBY, BACKUP) draw as little as sub-5 uA with RTC running, while wake-up time is sub-microsecond. The on-chip RTC with 32 kHz crystal maintains accurate timekeeping and scheduled wake-ups for periodic sensor sampling. The 12-bit ADC monitors battery voltage and sensor signals, while the DAC can drive analog sensor excitation. SERCOM channels connect to sub-GHz or BLE modules for low-duty-cycle wireless transmission. The Cortex-M0+ core executes sensor fusion and compression algorithms at 48 MHz before returning to deep sleep.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21J17D-AU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21J17D-AUT | ATSAMD21J18A-AU | ATSAMD20J17A-AU |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | TQFP-64 (Tray) | TQFP-64 (Tape & Reel) | TQFP-64 | TQFP-64 |
| Core | 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 | 256 KB | 128 KB |
| SRAM | 16 KB | 16 KB | 32 KB | 16 KB |
| USB 2.0 FS | Yes (on-chip transceiver) | Yes (on-chip transceiver) | Yes (on-chip transceiver) | No (SAM D20 family) |
| DAC | 10-bit, 2 channels | 10-bit, 2 channels | 10-bit, 2 channels | 10-bit, 1 channel |
| SERCOM | 6 | 6 | 6 | 6 |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
Key Differentiators
- Integrated USB 2.0 Full-Speed transceiver with on-chip 3.3V regulator (vs ATSAMD20J17A-AU)
- Double Flash and SRAM headroom for complex firmware stacks (vs ATSAMD21J17D-AU base)
- Latest silicon revision 'D' with improved errata fixes (vs ATSAMD21J17A-AU (rev A))
- Peripheral Touch Controller for up to 256 capacitive buttons (vs Generic Cortex-M0+ MCUs without PTC)
Design Notes
Place the 32.768 kHz crystal as close as possible to pins PA00 (XIN32) and PA01 (XOUT32) with traces routed as a guarded differential pair. Use crystal manufacturer's recommended load capacitor values (typically 6-10 pF) tied to GND. For USB applications, place the D+ and D- lines (PA24/PA25) as a 90-ohm differential pair with the same length, and route them away from switching nodes. A common-mode choke on the USB lines improves EMI immunity but is optional for most HID-class devices.
The ATSAMD21J17D-AU has separate VDDIO and VDDANA supply pins; both should be tied to the same 3.3V rail but each requires its own decoupling network. Use 100 nF ceramic capacitors on each VDDIO and VDDANA pin placed within 3 mm of the pin, plus a bulk 4.7 uF tantalum or ceramic at the IC entry. The internal core voltage regulator (VDDCORE) requires a 1 uF low-ESR ceramic decoupling capacitor. For low-power designs, disable unused peripherals in software and use the SUPC (Supply Controller) to manage backup mode entry for sub-microamp standby current.
A frequent pitfall is leaving the 32 kHz crystal pins unconfigured when not using an RTC crystal - this causes excess current draw and prevents STANDBY mode entry. Configure XIN32/XOUT32 as GPIO or disable the RTC clock source in SUPC before entering deep sleep. Another common error is using the internal DFLL without first calibrating against the 48 MHz reference at production test - this can result in USB timing failures above 2% clock accuracy. Always program the DFLL fine calibration value from the signature row at startup.
For the 64-pin TQFP package, ensure the exposed thermal pad (if present in the TQFP-64E variant) is soldered to a copper pour of at least 50 mm^2 to provide thermal relief at 48 MHz full load. Route all SERCOM signals as 50-ohm controlled-impedance traces if cable lengths exceed 50 mm. For USB D+/D- pair, maintain 90-ohm differential impedance. Avoid routing SERCOM and analog signals across noisy power regions - the SAM D21 has separate analog and digital ground planes internally that should not be bridged by signal traces.
Compliance Information
RoHS and REACH compliant per Microchip product page. 'AU' suffix indicates Green (Pb-free) compliance per JEDEC J-STD-609. Not AEC-Q100 qualified - automotive designs should consider ATSAMDA1 series or external monitoring IC.
