ATSAMD21J17A-AU - 48MHz Cortex-M0+ 128KB MCU 64-TQFP | Microchip
MPN: ATSAMD21J17A-AU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.08 | $4.08 |
| 10 | $3.79 | $37.90 |
| 100 | $3.42 | $342.00 |
| 500 | $2.96 | $1,480.00 |
| 1,000 | $2.62 | $2,620.00 |
ATSAMD21J17A-AU Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (Flash), working memory (SRAM), and peripherals onto one die. Within the embedded hierarchy, an MCU sits below microprocessors in computational capability but above basic logic ICs in functional density, providing self-sufficient intelligence for sensors, actuators, and human-interface subsystems. The Cortex-M0+ is ARM's smallest and most energy-efficient application processor core, optimised for deterministic interrupt response and low active/idle power. Microchip's SAM D21 family extends this core with Microchip-proprietary analog and timer IP, producing parts that compete head-to-head with STM32L0, EFM32, and NXP Kinetis KE series for ultra-low-power IoT sockets.
Key features include 48 MHz Cortex-M0+ core with single-cycle multiplier, 128 KB Flash plus 16 KB SRAM, full-speed USB 2.0 Device with on-the-go (OTG) support, up to six SERCOM configurable serial interfaces, 12-bit 1 MSPS ADC, 10-bit DAC, 5 timers/counters, two I2S interfaces, and a peripheral event system that allows peripherals to interact without CPU wakeup. The 64-pin TQFP footprint exposes 52 GPIO with 8 analog-capable pins, suiting boards that need USB, multiple UART/SPI/I2C buses, and motor-control PWM in parallel.
The SAM D21 architecture uses a separate AHB peripheral bus and a peripheral event fabric that lets SERCOM, ADC and timer blocks trigger one another in hardware, offloading the Cortex-M0+ core. The on-chip USB 2.0 Full-Speed transceiver and PHY eliminate external crystals for low-speed USB, and a 32 kHz internal RTC oscillator reduces BOM cost for battery-powered designs. Sampled in the SAM D21 datasheet, an LDO plus DC-DC SleepWalking power path enables measured run currents of a few mA at 48 MHz and sub-µA sleep currents.
Typical applications include consumer wearables, smart-home sensor hubs, USB HID peripherals, low-power wireless nodes, industrial metering and home-automation gateways. The 64-pin TQFP gives enough peripheral headroom for 4-wire SPI displays plus an SD card interface, and the AES engine supports secure firmware updates.
When designing with this MCU, ensure the 64-pin TQFP pad geometry matches the standard SAM D20/D21/DA1 land pattern so code written for one part can be ported across the family without PCB rework. Decoupling VDDIN with 100 nF + 1 µF and reserving a 32.768 kHz crystal footprint is recommended practice across the family.
This page consolidates live DigiKey/Mouser stock, drop-in compatible family variants, and practical design notes that the manufacturer datasheet alone does not present.
Drop-in alternatives for ATSAMD21J17A-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 ATSAMD21J17A-AU (same form factor and footprint) — differing in ADC, Operating Temperature, Package, DAC, USB.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD20J17A-AU
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →ATSAMD51J19A-AUT-EFP
✅ Drop-In✓ In Stock
$4.45 / Unit
View Datasheet →ATSAMDA1J16B-ABT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD21J17A-AU Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ (32-bit) |
| Family | SAM D21J (Functional Safety / FuSa) |
| Max CPU Clock | 48 MHz |
| Flash Memory | 128 KB |
| SRAM | 16 KB |
| Supply Voltage (VDDIN) | 1.62 V to 3.6 V |
| GPIO | 52 |
| ADC | 12-bit, up to 1 MSPS, 20 channels |
| DAC | 10-bit, 1 channel |
| USB | USB 2.0 Full-Speed Device + Host/OTG |
| SERCOM | Up to 6 configurable (UART/SPI/I2C) |
| Timers/Counters | 5 (TC) + 3 (TCC) for PWM |
| Operating Temperature | -40C to +85C |
| Package | 64-pin TQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
ATSAMD21J17A-AU 64-pin tqfp (10x10 mm) Pin Configuration Guide
Pin configuration for ATSAMD21J17A-AU (64-pin tqfp (10x10 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 ATSAMD21J17A-AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAMD21J17A-AU is suitable for 6 applications: USB HID Peripherals, Smart Home Sensor Hubs, Industrial Metering, Consumer Wearables, Home Automation Gateways, Battery-Powered IoT Nodes.
USB HID Peripherals
The ATSAMD21J17A-AU integrates a full-speed USB 2.0 Device and OTG controller with on-chip PHY, eliminating the need for an external USB transceiver and saving both BOM cost and PCB area. Its 48 MHz Cortex-M0+ core with 1.25 DMIPS/MHz comfortably runs HID class drivers plus custom vendor protocols, while 128 KB Flash and 16 KB SRAM provide headroom for compound HID descriptors, manufacturer pages, and embedded firmware upgrade logic. The 52 GPIO in the 64-pin TQFP expose enough pins for keyboard matrix scanning, LED indicators, and auxiliary UART/SPI ports that often accompany USB HID peripherals.
Recommended
Smart Home Sensor Hubs
With six SERCOM interfaces, the ATSAMD21J17A-AU can simultaneously host a BLE module over UART, an SPI sensor frontend, an I2C environmental sensor array, and a WiFi co-processor while still leaving spare buses for debugging. The Cortex-M0+ SleepWalking peripheral event fabric offloads sensor wake-up logic from the CPU, enabling multi-month battery life in door/window sensors and occupancy detectors. The 12-bit 1 MSPS ADC captures low-rate audio for glass-break or acoustic-event detection, and 128 KB Flash holds threaded sensor-fusion code plus OTA-capable bootloader.
Recommended
Industrial Metering
The ATSAMD21J17A-AU's 12-bit 1 MSPS ADC with 20 channels lets metering designs sample multi-phase voltage and current waveforms concurrently for accurate active/reactive power computation. Cortex-M0+ deterministic interrupt latency is well suited to IEC 62053-22 metering class requirements, and 128 KB Flash accommodates segmented firmware plus calibration tables. The 64-pin TQFP gives enough GPIO for segmented LCD drive, pulse-output, tariff inputs, and isolated serial communication buses (RS-485 via external transceiver).
Recommended
Consumer Wearables
The ATSAMD21J17A-AU's SleepWalking peripheral-event system and sub-µA deep-sleep current suit coin-cell powered wearables like fitness bands and BLE beacons. The Cortex-M0+ core wakes in single-digit microseconds to service sensor interrupts from the onboard 12-bit ADC, then returns to sleep without intervention. USB 2.0 Full-Speed enables wired charging-crate sync and firmware update without external drivers, while 128 KB Flash is enough room for device profiles, bootloader, and application code on the same die.
Recommended
Home Automation Gateways
In a home-automation gateway the ATSAMD21J17A-AU acts as a protocol translator between Zigbee/WiFi/Thread radios and local RS-485 or KNX bus. Six SERCOM ports host multiple radios in parallel, and USB 2.0 OTG supports local commissioning dongles or external mass storage for log buffering. The 12-bit ADC monitors the rail supply for brown-out detection, and 128 KB Flash holds the secure bootloader plus encrypted OTA pipeline to keep firmware integrity throughout multi-year deployments.
Recommended
Battery-Powered IoT Nodes
The ATSAMD21J17A-AU's measured active-supply-current and sub-µA deep-sleep power make it a workhorse for off-grid IoT nodes running from a single 18650 cell or 2xAA pack. The internal DC-DC SleepWalking regulator supplies the Cortex-M0+ core from a single 1.62 V to 3.6 V battery, eliminating the external switching regulator typically required at these voltage ranges and improving efficiency at low duty cycles. Its 12-bit ADC reads battery voltage directly through an internal divider, supporting coulomb-counting or simple voltage fuel-gauge algorithms across multi-year deployments.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21J17A-AU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD20J17A-AU | ATSAMD51J19A-AUT | ATSAMDA1J16B-ABT |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-pin TQFP (10x10 mm) | 64-pin TQFP (10x10 mm) - same | 64-pin TQFP (10x10 mm) - same | 64-pin TQFP (10x10 mm) - same |
| Core | Cortex-M0+ @ 48 MHz | Cortex-M0+ @ 48 MHz | Cortex-M4F @ 120 MHz | Cortex-M0+ @ 48 MHz |
| Flash | 128 KB | 128 KB | 512 KB | 64 KB |
| SRAM | 16 KB | 16 KB | 192 KB | 8 KB |
| USB | Yes (FS Device + OTG) | No | Yes (FS + HS capable) | Yes (FS Device) |
| CAN-FD | No | No | Optional | Yes |
| Automotive Grade | No (Functional Safety FuSa variant available) | No | No | Yes (automotive qualified) |
Key Differentiators
- Functional Safety (FuSa) variant with same part number (vs ATSAMD20J17A-AU)
- USB 2.0 Full-Speed with on-chip PHY (vs ATSAMD20J17A-AU)
- Pin-compatible upgrade path to Cortex-M4F (vs ATSAMD51J19A-AUT)
Design Notes
Place a 100 nF X7R ceramic decoupling capacitor directly on each VDDIN and VDDIO pin pair, with a 4.7 µF bulk capacitor on the main rail. The internal DC-DC SleepWalking converter needs an external 1 µF capacitor on the DECDU pin for energy transfer; without it the part will overcurrent the internal FETs and trigger brown-out reset.
Route the 32.768 kHz crystal traces as short symmetric loops with a ground guard ring, and keep them at least 2 mm away from any switching signal like USB D+/D- or PWM outputs. The 64-pin TQFP exposes a separate AVDD analog supply that should be filtered with a ferrite bead and 100 nF + 10 µF decoupling for ADC noise floor stability.
Ensure the BOOTPROT fuse is set before production so the secure bootloader can verify firmware signatures; unconfigured BOOTPROT lets an attacker recover keys through debug. Also reserve the NVMCTRL row-write timing margin of 2.4 ms and disable interrupts during row-write operations, or Flash contents can be silently corrupted.
Compliance Information
RoHS and REACH compliant per Microchip product page. The ATSAMD21J17A-AU is the SAM D21J FuSa variant (Functional Safety), providing safety manuals and software libraries for IEC 60730 Class B; for AEC-Q100 automotive qualification, use the SAM DA1 family ATSAMDA1J16B-ABT instead.
