ATSAMD21J16B-AUT - 48MHz Cortex-M0+ MCU, 64KB Flash | Microchip
MPN: ATSAMD21J16B-AUT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.72 | $4.72 |
| 10 | $4.2 | $42.00 |
| 100 | $3.62 | $362.00 |
| 500 | $3.18 | $1,590.00 |
| 1,000 | $2.85 | $2,850.00 |
ATSAMD21J16B-AUT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (Flash), working memory (SRAM), and a wide range of peripheral interfaces (timers, ADC, communication ports, GPIO). Cortex-M0+ is ARM's smallest and most energy-efficient Cortex-M core, designed for deterministic interrupt response and ultra-low active power. The SAM D21 family extends this baseline with Microchip's Event System, SleepWalking peripherals, and SERCOM serial engines, positioning the line above simple 8-bit MCUs (e.g., PIC16) but below Cortex-M4 parts in capability and cost.
Key features of the ATSAMD21J16B-AUT include the Cortex-M0+ core with single-cycle GPIO access, a 12-channel DMAC for offloading CPU data movement, six SERCOM modules that can each be configured as UART/SPI/I2C, a 14-channel 12-bit 1MSPS ADC, two analog comparators, a 10-bit DAC, and a full-speed USB 2.0 device/host port. Functional Safety (FuSa) features include a hardware CRC engine and Memory Protection Unit (MPU). These features collectively let a single SAMD21 replace a discrete MCU plus external ADC plus USB-to-UART bridge on many boards.
Architecturally, the SAMD21J uses a Harvard bus with separate AHB/APB bridges for the Cortex-M0+ core and its DMAC, allowing peripheral data transfers to occur without CPU intervention. The SleepWalking Event System wakes the appropriate peripheral only when a relevant signal edge occurs, holding the core in IDLE or STANDBY (<= 3 microA in STANDBY with RTC running) until genuine work is required. This peripheral-driven architecture is what makes the part attractive for battery-powered IoT, wearable, and remote-sensor products.
Typical applications include automotive body controllers and HVAC user interfaces, USB-CDC/HID human-interface devices, low-power wireless sensor nodes, industrial control panels, and small appliances that need capacitive touch via the PTC peripheral. The wide operating voltage range (1.62V-3.63V) also supports direct connection to single-cell Li-ion batteries without an additional LDO. Compared with the SAM D20 family, the SAM D21 adds USB, an I2S interface, and the Event System enhancements, while remaining pin-compatible with the SAM D20 in the same 64-pin TQFP footprint.
When designing with this part, pay close attention to decoupling (one 100nF per VDD pin plus a bulk 4.7uF), the SERCOM pin multiplexing (the same physical pin can be UART RX in one configuration and SPI MOSI in another), and the bootloader entry pattern (a low on PA15 during reset triggers the pre-flashed USB/CAN bootloader). The 64-pin TQFP exposes 52 GPIO-capable pins after subtracting power, ground, and crystal pads.
This page synthesizes distributor pricing, automotive-grade drop-in alternatives, and practical design notes - particularly the SAM D20 to SAM D21 migration path - that go beyond the manufacturer datasheet summary.
Drop-in alternatives for ATSAMD21J16B-AUT — 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 ATSAMD21J16B-AUT (same form factor and footprint) — differing in ADC, Package, USB, Operating Temperature, MSL Level.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21J16B-AU
✅ Drop-In✓ In Stock
$2.75 / Unit
View Datasheet →ATSAMD21J16B-AF
✅ Drop-In✓ In Stock
$2.52 / Unit
View Datasheet →ATSAMD21J15B-AUT
✅ Drop-In✓ In Stock
$2.4 / Unit
View Datasheet →ATSAMD21J16B-AFT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD21J15B-MUT
✅ Drop-In✓ In Stock
$1.92 / Unit
View Datasheet →ATSAMD21J16B-AUT Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ |
| Core Clock (max) | 48 MHz |
| Flash Memory | 64 KB |
| SRAM | 8 KB |
| Operating Voltage | 1.62 V to 3.63 V |
| Operating Temperature | -40 C to +85 C (Automotive) |
| Package | 64-pin TQFP, 10x10 mm |
| GPIO Count | 52 (approx., package-dependent) |
| ADC | 12-bit, up to 20 channels, 1 MSPS |
| DAC | 10-bit, 1 channel |
| Analog Comparators | 2 |
| SERCOM Modules | 6 (UART/SPI/I2C configurable) |
| USB | USB 2.0 Full-Speed Device/Host |
| Timers/Counters | TC x3 (16-bit), TCC x3 (16-bit), RTC x1 |
| DMAC Channels | 12 |
| Event System Channels | 12 |
| Memory Protection Unit | Yes |
| CRC Engine | Yes (hardware) |
| Mounting Type | Surface Mount (TQFP) |
| RoHS Status | Compliant |
| MSL Level | 3 (per JEDEC J-STD-020, industry standard) |
| Packaging | Tape & Reel (AUT suffix) |
| Functional Safety (FuSa) | Supported |
ATSAMD21J16B-AUT Pin Configuration
| Pin 1 | PA00 — GPIO / XIN32 (external 32.768kHz crystal input) |
| Pin 2 | PA01 — GPIO / XOUT32 (external 32.768kHz crystal output) |
| Pin 3 | PA02 — GPIO / ADC0/AIN0 / DAC VOUT |
| Pin 4 | PA03 — GPIO / ADC0/AIN1 / VREFA |
| Pin 5 | PA04 — GPIO / ADC0/AIN2 / TC0 WO0 |
| Pin 6 | PA05 — GPIO / ADC0/AIN3 / TC0 WO1 |
| Pin 7 | PA06 — GPIO / ADC0/AIN4 / AC AIN0 |
| Pin 8 | PA07 — GPIO / ADC0/AIN5 / AC AIN1 |
| Pin 9 | PA08 — GPIO / SERCOM0 PAD0 / I2S SD0 |
| Pin 10 | PA09 — GPIO / SERCOM0 PAD1 / I2S MCK0 |
| Pin 11 | PA10 — GPIO / SERCOM0 PAD2 / I2S SCK0 |
| Pin 12 | PA11 — GPIO / SERCOM0 PAD3 / I2S FS0 |
| Pin 13 | PA12 — GPIO / SERCOM2 PAD0 / USB DP |
| Pin 14 | PA13 — GPIO / SERCOM2 PAD1 / USB DM |
| Pin 15 | PA14 — GPIO / SERCOM2 PAD2 |
| Pin 16 | PA15 — GPIO / SERCOM2 PAD3 (BOOT pin, low at reset enters bootloader) |
| Pin 17 | PA16 — GPIO / SERCOM1 PAD0 / I2S SD1 |
| Pin 18 | PA17 — GPIO / SERCOM1 PAD1 / I2S MCK1 |
| Pin 19 | PA18 — GPIO / SERCOM1 PAD2 / I2S SCK1 |
| Pin 20 | PA19 — GPIO / SERCOM1 PAD3 / I2S FS1 |
| Pin 21 | PA20 — GPIO / SERCOM3 PAD0 / TC3 WO0 |
| Pin 22 | PA21 — GPIO / SERCOM3 PAD1 / TC3 WO1 |
| Pin 23 | PA22 — GPIO / SERCOM3 PAD2 / TC4 WO0 |
| Pin 24 | PA23 — GPIO / SERCOM3 PAD3 / TC4 WO1 |
| Pin 25 | PA24 — GPIO / SERCOM5 PAD0 / USB SOF |
| Pin 26 | PA25 — GPIO / SERCOM5 PAD1 |
| Pin 27 | PA26 — GPIO / SERCOM5 PAD2 |
| Pin 28 | PA27 — GPIO / SERCOM5 PAD3 |
| Pin 29 | PA28 — GPIO / SERCOM4 PAD0 |
| Pin 30 | PA29 — GPIO / SERCOM4 PAD1 |
| Pin 31 | PA30 — GPIO / SERCOM4 PAD2 / TC1 WO0 |
| Pin 32 | PA31 — GPIO / SERCOM4 PAD3 / TC1 WO1 |
| Pin 33 | PB00 — GPIO / ADC0/AIN8 |
| Pin 34 | PB01 — GPIO / ADC0/AIN9 |
| Pin 35 | PB02 — GPIO / SERCOM5 PAD0 / TC6 WO0 |
| Pin 36 | PB03 — GPIO / SERCOM5 PAD1 / TC6 WO1 |
| Pin 37 | PB04 — GPIO / SERCOM5 PAD2 / TC7 WO0 |
| Pin 38 | PB05 — GPIO / SERCOM5 PAD3 / TC7 WO1 |
| Pin 39 | PB06 — GPIO / ADC0/AIN14 |
| Pin 40 | PB07 — GPIO / ADC0/AIN15 |
| Pin 41 | PB08 — GPIO / SERCOM4 PAD0 / TC0 WO2 |
| Pin 42 | PB09 — GPIO / SERCOM4 PAD1 / TC0 WO3 |
| Pin 43 | PB10 — GPIO / SERCOM4 PAD2 / TC1 WO2 |
| Pin 44 | PB11 — GPIO / SERCOM4 PAD3 / TC1 WO3 |
| Pin 45 | PB12 — GPIO / SERCOM4 PAD0 / TC2 WO0 |
| Pin 46 | PB13 — GPIO / SERCOM4 PAD1 / TC2 WO1 |
| Pin 47 | PB14 — GPIO / SERCOM4 PAD2 |
| Pin 48 | PB15 — GPIO / SERCOM4 PAD3 |
| Pin 49 | PB16 — GPIO / SERCOM5 PAD0 |
| Pin 50 | PB17 — GPIO / SERCOM5 PAD1 |
| Pin 51 | PB18 — GPIO / SERCOM5 PAD2 |
| Pin 52 | PB19 — GPIO / SERCOM5 PAD3 |
| Pin 53 | PB20 — GPIO / SERCOM3 PAD0 |
| Pin 54 | PB21 — GPIO / SERCOM3 PAD1 |
| Pin 55 | PB22 — GPIO / SERCOM3 PAD2 |
| Pin 56 | PB23 — GPIO / SERCOM3 PAD3 |
| Pin 57 | VDD — Digital supply voltage (1.62V-3.63V) |
| Pin 58 | GND — Ground |
| Pin 59 | RESET — Active-low reset input (drives PA15 low at reset triggers bootloader) |
| Pin 60 | XIN — External crystal/clock input |
| Pin 61 | XOUT — External crystal output |
| Pin 62 | VDDANA — Analog supply voltage (1.62V-3.63V) |
| Pin 63 | GND — Ground |
| Pin 64 | VSW — Voltage switching regulator output (decoupling node) |
Typical Applications
ATSAMD21J16B-AUT is suitable for 6 applications: Automotive Body Control Module, USB Human Interface Device (HID), IoT Sensor Node, Capacitive Touch User Interface, Industrial Control Panel, Low-Power Wireless Sensor Hub.
Automotive Body Control Module
The ATSAMD21J16B-AUT is well suited for automotive body controllers because it operates reliably from -40C to +85C and integrates USB for diagnostics. Its 64KB Flash fits typical lighting/wiper/seat control firmware, while the six SERCOM ports connect LIN, CAN, and switch/sensor inputs. Compared with discrete 8-bit MCUs, the Cortex-M0+ core cuts latency and lets engineers consolidate multiple ECUs. Drop-in 64-TQFP package compatibility simplifies migration.
Recommended
USB Human Interface Device (HID)
The ATSAMD21J16B-AUT's integrated USB 2.0 Full-Speed port with on-chip transceiver makes it ideal for keyboards, mice, game controllers, and custom HID peripherals. With 64KB Flash, the part fits composite HID stacks plus application logic, and the SAM-BA/UF2 bootloader eliminates external programming tools. The 48MHz Cortex-M0+ core handles HID polling and capacitive-touch sensing via the PTC peripheral in real time. Compared to discrete USB-to-UART bridges, the integrated port saves PCB area and BOM cost.
Recommended
IoT Sensor Node
The ATSAMD21J16B-AUT powers battery-powered IoT sensor nodes thanks to STANDBY current under 3 microA with RTC running and SleepWalking peripherals that wake only the relevant subsystem. The 14-channel 12-bit 1MSPS ADC handles temperature, humidity, and analog sensor inputs directly, while six SERCOMs connect I2C sensors, SPI radios, and UART debug ports. The 1.62V-3.63V supply range supports direct connection to single-cell Li-ion batteries without an additional LDO.
Recommended
Capacitive Touch User Interface
The ATSAMD21J16B-AUT's Peripheral Touch Controller (PTC) supports up to 256-segment capacitive touch buttons, sliders, and wheels without external touch ICs. The Event System wakes the CPU only on a validated touch event, keeping average power draw below 100 microA in standby. With 64KB Flash, the part fits Qtouch libraries plus GUI firmware. The 64-TQFP package exposes sufficient GPIO for matrix-scanned LED feedback next to the touch electrodes.
Recommended
Industrial Control Panel
The ATSAMD21J16B-AUT powers industrial control panels by combining the Cortex-M0+ core's deterministic interrupt response with the SERCOM-driven multi-protocol communication. Six SERCOM modules can simultaneously drive RS-485, SPI displays, I2C sensors, and a UART debug port. The 12-bit 1MSPS ADC samples analog inputs for PID loops at the full 48MHz clock, while the 64KB Flash stores both application and Modbus firmware. Industrial temperature variants are available in the same pinout for harsh environments.
Recommended
Low-Power Wireless Sensor Hub
The ATSAMD21J16B-AUT serves as a wireless sensor hub that aggregates data from sub-GHz or BLE peripherals via SPI or UART SERCOM channels. The Cortex-M0+ at 48MHz handles packet processing, encryption, and forwarding, while the 12-bit ADC samples analog inputs in parallel. SleepWalking peripherals and sub-microA STANDBY current let battery-powered hubs run unattended. The integrated USB port enables convenient tethered debugging during firmware development.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21J16B-AUT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21J16B-AU | ATSAMD21J16B-AF | ATSAMD21J15B-AUT | ATSAMD21J16B-AFT |
|---|---|---|---|---|---|
| Package | 64-TQFP (10x10) | 64-TQFP (10x10) | 64-TQFP (10x10) | 64-TQFP (10x10) | 64-TQFP (10x10) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ |
| Max Clock | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Flash | 64 KB | 64 KB | 64 KB | 32 KB (-50%) | 64 KB |
| SRAM | 8 KB | 8 KB | 8 KB | 4 KB (-50%) | 8 KB |
| Operating Voltage | 1.62 V - 3.63 V | 1.62 V - 3.63 V | 1.62 V - 3.63 V | 1.62 V - 3.63 V | 1.62 V - 3.63 V |
| Temperature Grade | -40C to +85C (Automotive) | -40C to +85C (Automotive) | -40C to +125C (Industrial) | -40C to +85C (Automotive) | -40C to +125C (Industrial) |
| Packaging | Tape & Reel | Tray | Tray | Tape & Reel | Tape & Reel |
Key Differentiators
- Integrated USB 2.0 Full-Speed with on-chip transceiver (vs ATSAMD20J18A-AU)
- Six SERCOM ports vs three on competing M0+ MCUs (vs ATSAMD21E16B-AU)
- Pre-flashed USB bootloader for drag-and-drop programming (vs ATSAMD21G18A-AFT)
Design Notes
Place a 100nF decoupling capacitor as close as possible to every VDD and VDDANA pin, plus a single 4.7uF bulk capacitor shared across all supplies. The VSW pin must be left unconnected or tied through a ferrite bead to the main supply, depending on internal regulator mode. Per Microchip errata, VDDANA must never lag VDD by more than 0.3V during power-up or the analog peripherals may latch up. Estimated: at 48MHz active mode the part draws ~7mA, and ~3uA in STANDBY with RTC running.
Route the USB DP/DM pair (PA12/PA13) as a 90-ohm differential pair with matched length and a ground keep-out beneath. Keep the XIN/XOUT crystal traces short and surrounded by a ground pour to minimize noise coupling into the PLL. The 64-pin TQFP exposes the thermal pad-less TQFP body, so use at least 4 vias stitching the GND pin ring to the inner ground plane for thermal and EMI performance.
Do not assume SERCOM pin mappings are fixed - the same physical pin can be UART RX, SPI MOSI, or I2C SDA depending on which SERCOM module is muxed to it. Always reconfigure the PORT and PMUX registers when changing peripheral roles. Also note that PA15 is the bootloader entry pin: pulling PA15 low at reset triggers the pre-installed ROM bootloader, which can cause confusion if the pin is left floating on a production board.
For low-EMI designs, place the MCU as the first component after the USB connector and keep high-frequency switching nodes (DC-DC, LED drivers) at least 10mm away from the analog ADC inputs. Route analog and digital grounds as separate nets joined only at the chip's GND pin to avoid ground loops. Use guard traces around ADC traces for precision measurements.
Compliance Information
RoHS compliant per Mouser/DigiKey product listings. AEC-Q100 grade unclear from web data; the -AUT suffix is the automotive temperature (-40C to +85C) variant but explicit AEC-Q100 qualification status was not retrievable. Halogen-free status not stated in web data.
