ATSAMD21J17D-AF - ARM Cortex-M0+ 48MHz MCU, 128KB Flash, TQFP-64 | Microchip
MPN: ATSAMD21J17D-AF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.2 | $6.20 |
| 10 | $5.55 | $55.50 |
| 100 | $4.92 | $492.00 |
| 500 | $4.4 | $2,200.00 |
| 1,000 | $3.95 | $3,950.00 |
ATSAMD21J17D-AF Overview
The ARM Cortex-M0+ is the smallest and most energy-efficient member of the Cortex-M family, designed for deeply embedded 8/16-bit replacement workloads. A microcontroller (MCU) integrates a CPU core, non-volatile program memory (Flash), volatile working memory (SRAM), and a mix of analog and digital peripherals onto a single die. Compared with classic 8051 or PIC microcontrollers, Cortex-M0+ parts deliver a modern 32-bit Thumb-2 instruction set, deterministic nested-vector interrupts, and a vendor-neutral AMBA peripheral bus, while retaining ultra-low standby current. The SAMD21 family specifically adds Microchip's Event System (inter-peripheral signalling without CPU wake) and SleepWalking peripherals that remain clocked while the core sleeps.
Key specifications of the ATSAMD21J17D-AF include 48 MHz maximum CPU clock, 128 KB Flash with 4 KB read-while-write region, 16 KB SRAM, six SERCOM channels configurable as UART/SPI/I2C, one full-speed USB 2.0 device port, up to 6 communication interfaces, and up to 52 programmable I/O pins. The integrated 12-bit ADC delivers up to 350 ksps, the 10-bit DAC up to 350 ksps, and the peripheral event system supports 12 channels. Operating voltage spans 1.62 V to 3.63 V with multiple low-power sleep modes down to sub-microamp standby.
Architecturally, the ATSAMD21J17D-AF uses a single-cycle hardware multiplier, separate Flash and SRAM AHB-Lite buses, and a peripheral bridge that decouples SERCOM and event traffic from the CPU. The Full-Speed USB device controller includes an on-chip transceiver and internal pull-up, eliminating external components for HID, CDC, or vendor-class USB applications. The integrated SERCOM blocks can be reassigned at runtime, providing design flexibility when moving pins between UART, SPI, and I2C.
Typical applications include home automation controllers (Zigbee/Matter bridges, smart thermostats), consumer products (USB HID peripherals, wearables), metering (gas/water/electricity counters with LCD), and industrial sensor hubs (Modbus nodes, 4-20 mA loop replacements). The extended 125°C temperature rating also supports automotive aftermarket and outdoor industrial use cases.
When designing with this MCU, allocate at least one SERCOM channel for UART debug console, plan the USB DP/DN trace impedance for 90 ohm differential, and use the Event System to wake the CPU on peripheral triggers instead of polling. The 128 KB Flash and 16 KB SRAM are sufficient for an RTOS kernel plus an application, but compiler -Os and a memory pool allocator are recommended for production builds.
Drop-in alternatives for ATSAMD21J17D-AF — 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-AF (same form factor and footprint) — differing in MSL Level, Package, ADC, DAC, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21J17A-AF
✅ Drop-In✓ In Stock
$2.75 / Unit
View Datasheet →ATSAMD21J17A-AUT
✅ Drop-In✓ In Stock
$3.3 / Unit
View Datasheet →ATSAMD21J18D-AF
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD21J16D-AF
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD21J17D-AF Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Series | SAM D21J, Functional Safety (FuSa) |
| Core | ARM Cortex-M0+ |
| Core Size | 32-Bit |
| Maximum CPU Clock | 48 MHz |
| Program Memory Size | 128 KB Flash (128K x 8) |
| Program Memory Type | Flash |
| RAM Size | 16 KB |
| Read-While-Write Region | 4 KB |
| Number of I/O Pins | 52 (maximum, package-dependent) |
| Supply Voltage | 1.62 V to 3.63 V |
| Operating Temperature | -40 °C to +125 °C (extended) |
| Package | 64-TQFP (10 x 10 mm) |
| Mounting Type | Surface Mount |
| ADC | 12-bit, up to 20 channels |
| DAC | 10-bit, 1 channel |
| USB | Full-Speed USB 2.0 Device with on-chip transceiver |
| Communication Interfaces | Up to 6 SERCOM (UART/SPI/I2C), I2S, USB |
| Timers | TC x 3, TCC x 2, RTC x 1 |
| MSL Level | 3 (168 hours, JEDEC J-STD-020) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
ATSAMD21J17D-AF Pin Configuration
| Pin 1 | VDDIO — Digital I/O supply voltage (1.62V to 3.63V) |
| Pin 2 | PA02 — General-purpose I/O / ADC AIN[0] |
| Pin 3 | PA03 — General-purpose I/O / ADC AIN[1] / REF positive reference |
| Pin 4 | PA04 — General-purpose I/O / ADC AIN[2] |
| Pin 5 | PA05 — General-purpose I/O / ADC AIN[3] |
| Pin 6 | PA06 — General-purpose I/O / ADC AIN[4] |
| Pin 7 | PA07 — General-purpose I/O / ADC AIN[5] |
| Pin 8 | VDDANA — Analog supply voltage |
| Pin 9 | GND — Ground |
| Pin 10 | PA08 — General-purpose I/O / ADC AIN[6] (NMI - non-maskable interrupt) |
| Pin 11 | PA09 — General-purpose I/O / ADC AIN[7] |
| Pin 12 | PA10 — General-purpose I/O / ADC AIN[8] / SERCOM2 PAD[2] |
| Pin 13 | PA11 — General-purpose I/O / ADC AIN[9] |
| Pin 14 | PA12 — General-purpose I/O / ADC AIN[10] |
| Pin 15 | PA13 — General-purpose I/O / ADC AIN[11] |
| Pin 16 | PA14 — General-purpose I/O / SERCOM2 PAD[2] |
| Pin 17 | PA15 — General-purpose I/O / SERCOM2 PAD[3] |
| Pin 18 | PA16 — General-purpose I/O / SERCOM1 PAD[0] / I2S FS |
| Pin 19 | PA17 — General-purpose I/O / SERCOM1 PAD[1] / I2S SCK |
| Pin 20 | PA18 — General-purpose I/O / SERCOM1 PAD[2] / I2S MCK |
| Pin 21 | PA19 — General-purpose I/O / SERCOM1 PAD[3] / I2S SD |
| Pin 22 | PA20 — General-purpose I/O / SERCOM5 PAD[2] |
| Pin 23 | PA21 — General-purpose I/O / SERCOM5 PAD[3] |
| Pin 24 | PA22 — General-purpose I/O / SERCOM3 PAD[0] |
| Pin 25 | PA23 — General-purpose I/O / SERCOM3 PAD[1] |
| Pin 26 | PA24 — General-purpose I/O / SERCOM3 PAD[2] |
| Pin 27 | PA25 — General-purpose I/O / SERCOM3 PAD[3] |
| Pin 28 | VDDCORE — Internal core voltage regulator output (1.2V) - decouple |
| Pin 29 | GND — Ground |
| Pin 30 | PA27 — General-purpose I/O |
| Pin 31 | PA28 — General-purpose I/O / Reset input |
| Pin 32 | PA30 — General-purpose I/O / SWCLK (programming/debug) |
| Pin 33 | PA31 — General-purpose I/O / SWDIO (programming/debug) |
| Pin 34 | PB00 — General-purpose I/O |
| Pin 35 | PB01 — General-purpose I/O |
| Pin 36 | PB02 — General-purpose I/O / SERCOM5 PAD[0] |
| Pin 37 | PB03 — General-purpose I/O / SERCOM5 PAD[1] |
| Pin 38 | PB04 — General-purpose I/O |
| Pin 39 | PB05 — General-purpose I/O |
| Pin 40 | PB06 — General-purpose I/O |
| Pin 41 | PB07 — General-purpose I/O |
| Pin 42 | PB08 — General-purpose I/O / SERCOM4 PAD[0] |
| Pin 43 | PB09 — General-purpose I/O / SERCOM4 PAD[1] |
| Pin 44 | PB10 — General-purpose I/O / SERCOM4 PAD[2] |
| Pin 45 | PB11 — General-purpose I/O / SERCOM4 PAD[3] |
| Pin 46 | PB12 — General-purpose I/O / SERCOM0 PAD[0] |
| Pin 47 | PB13 — General-purpose I/O / SERCOM0 PAD[1] |
| Pin 48 | PB14 — General-purpose I/O / SERCOM0 PAD[2] |
| Pin 49 | PB15 — General-purpose I/O / SERCOM0 PAD[3] |
| Pin 50 | PB16 — General-purpose I/O / SERCOM1 PAD[0] |
| Pin 51 | PB17 — General-purpose I/O / SERCOM1 PAD[1] |
| Pin 52 | PB18 — General-purpose I/O / SERCOM1 PAD[2] |
| Pin 53 | PB19 — General-purpose I/O / SERCOM1 PAD[3] |
| Pin 54 | PB20 — General-purpose I/O / SERCOM3 PAD[0] |
| Pin 55 | PB21 — General-purpose I/O / SERCOM3 PAD[1] |
| Pin 56 | PB22 — General-purpose I/O / SERCOM3 PAD[2] |
| Pin 57 | PB23 — General-purpose I/O / SERCOM3 PAD[3] |
| Pin 58 | USB_DM — USB Full-Speed data minus (D-) |
| Pin 59 | USB_DP — USB Full-Speed data plus (D+) |
| Pin 60 | VDDIO — Digital I/O supply voltage (1.62V to 3.63V) |
| Pin 61 | GND — Ground |
| Pin 62 | GND — Ground |
| Pin 63 | PA01 — General-purpose I/O / DAC VOUT |
| Pin 64 | PA00 — General-purpose I/O / XIN (32.768 kHz crystal) |
Typical Applications
ATSAMD21J17D-AF is suitable for 6 applications: Home Automation Hub, USB HID Peripheral, Smart Metering End Point, Industrial Sensor Hub, Consumer Wearable Device, Automotive Aftermarket Module.
Home Automation Hub
The ATSAMD21J17D-AF fits home automation hubs where 128 KB Flash fits Zigbee/Matter bridge firmware, 16 KB SRAM serves TLS session buffers, and 48 MHz Cortex-M0+ handles message routing with deterministic interrupt latency. The 6 SERCOM channels map directly to UART for debug console, SPI for the radio module, I2C for sensors, and I2S for audio chime features, while USB enables firmware upgrade via PC tether. The 1.62-3.63 V range supports 3.3 V wall-adapter and battery-backup topologies simultaneously.
Recommended
USB HID Peripheral
The ATSAMD21J17D-AF's integrated full-speed USB 2.0 device controller with on-chip transceiver and internal pull-up removes the external 5 V-tolerant buffer normally required for keyboards, mice, and custom HID devices. The 48 MHz core plus 128 KB Flash easily fits USB stacks from TinyUSB or LUFA, leaving headroom for product firmware. The 52 programmable I/Os support 22+ key matrix or 64 mechanical-key scanning with room for RGB underglow LED drivers.
Recommended
Smart Metering End Point
The ATSAMD21J17D-AF suits gas, water, and electricity metering end points where its low-power SleepWalking peripherals enable ADC sampling of sensor signals while the core sleeps, drawing sub-microamp standby current on battery-only installations. The 128 KB Flash stores metrology algorithms, calibration tables, and DLMS/COSEM protocol stacks; the 16 KB SRAM buffers burst consumption data. The extended -40 to +125 °C rating matches outdoor or basement meter enclosures without derating.
Recommended
Industrial Sensor Hub
For industrial sensor hubs aggregating Modbus RTU, 4-20 mA loop, and discrete I/O channels, the ATSAMD21J17D-AF's 48 MHz core plus 6 SERCOM channels map cleanly to multiple UART/SPI/I2C buses without external transceivers. The 12-bit ADC handles 4-20 mA loop measurements with external current-sense resistors, while the 10-bit DAC generates excitation signals for bridge sensors. The extended temperature rating covers factory-floor enclosures and outdoor cabinet installations.
Recommended
Consumer Wearable Device
Wearable designs (fitness bands, smart watches, medical patches) benefit from the ATSAMD21J17D-AF's 1.62-3.63 V supply range (single Li-ion / coin cell support), Cortex-M0+ efficiency, and SleepWalking peripherals that wake the CPU only on heart-rate sensor events. The integrated 12-bit ADC captures bioimpedance and PPG signals, the 10-bit DAC drives LED bias, and the SERCOM I2C connects the IMU and heart-rate sensor with no external glue logic.
Recommended
Automotive Aftermarket Module
Although not AEC-Q100 qualified, the ATSAMD21J17D-AF's extended 125 °C temperature rating and rugged 64-TQFP package suit aftermarket automotive accessories (telematics dongles, OBD-II adapters, GPS loggers) where cost is primary. The full-speed USB device port emulates a serial port for OBD-II pass-through, the Cortex-M0+ runs the CAN-to-USB bridge, and the 128 KB Flash stores trip data. For OEM automotive designs, use the ATSAMDA1J17D-AF AEC-Q100 variant instead.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21J17D-AF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21J17A-AF | ATSAMD21J17A-AUT | ATSAMD21J18D-AF | ATSAMD21J16D-AF |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-TQFP (10x10 mm) | 64-TQFP (10x10 mm) - same | 64-TQFP (10x10 mm) - same | 64-TQFP (10x10 mm) - same | 64-TQFP (10x10 mm) - same |
| Core / Architecture | ARM Cortex-M0+ 32-bit | ARM Cortex-M0+ 32-bit | ARM Cortex-M0+ 32-bit | ARM Cortex-M0+ 32-bit | ARM Cortex-M0+ 32-bit |
| Maximum CPU Clock | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Flash Memory | 128 KB | 128 KB | 128 KB | 256 KB | 64 KB |
| SRAM | 16 KB | 16 KB | 16 KB | 32 KB | 8 KB |
| USB 2.0 FS Device | Yes (on-chip transceiver) | Yes | Yes | Yes | Yes |
| Silicon Revision | Rev D (latest) | Rev A (older) | Rev A (older) | Rev D | Rev D |
| Operating Temperature | -40 °C to +125 °C (extended) | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C | -40 °C to +125 °C |
Key Differentiators
- Latest silicon revision (Rev D) with errata fixes (vs ATSAMD21J17A-AF)
- More Flash and SRAM headroom in pin-compatible upgrade (vs ATSAMD21J18D-AF)
- Lowest cost pin-compatible downgrade (vs ATSAMD21J16D-AF)
Design Notes
Decoupling: Place a 0.1 µF ceramic capacitor within 3 mm of every VDD, VDDIO, and VDDANA pin, with a 1 µF bulk capacitor on the VDD rail. The on-chip core regulator requires a 1 µF decoupling cap on VDDCORE (pin 28). Estimated: at 48 MHz active and 3.3 V supply, the MCU draws ~9 mA active and ~2 µA in backup mode (sleep with full SRAM retention). Routing AVDD separately from VDDIO via a ferrite bead is recommended when ADC measurements must reject digital switching noise.
USB trace layout: Route USB DP (pin 59) and USB DM (pin 58) as a 90 ohm differential pair on the top layer with continuous reference ground plane beneath. Match lengths to within 150 mil, keep series in-line components to a minimum, and avoid stubs. The TQFP-64 thermal pad (GND pins 9, 29, 61, 62) should be soldered to a continuous copper pour to reduce theta-JA for hot-temperature applications. For JTAG/SWD programming, route PA30 (SWCLK) and PA31 (SWDIO) together with the reset pin to a 10-pin Cortex Debug header.
Clock configuration: GCLK0 must be configured for the CPU before any peripheral clock distribution is enabled, otherwise peripherals may lock up. ADC readings can drift if the analog reference source is unstable - use the internal 1.0 V bandgap with the 1/2 VDDANA reference for ratiometric measurements. The 32.768 kHz crystal (XIN/XOUT on PA00/PA01) must use a low-ESR crystal with the recommended load capacitors; otherwise the GCLK failure detection will trigger a system reset. Estimated: full chip erase at 3.3 V takes ~80 ms via the NVMCTRL.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - use ATSAMDA1J17D-AF variant for automotive OEM. Extended 125 °C operating temperature (AF suffix).