ATSAMD21J15B-MUT - 48MHz Cortex-M0+ 32KB Flash MCU
MPN: ATSAMD21J15B-MUT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $3.07 | $30.70 |
| 100 | $2.71 | $271.00 |
| 500 | $2.44 | $1,220.00 |
| 1,000 | $2.18 | $2,180.00 |
| 3,000 | $1.92 | $5,760.00 |
ATSAMD21J15B-MUT Overview
An ARM Cortex-M0+ microcontroller is a 32-bit RISC processor core optimized for energy-efficient embedded applications, commonly used in IoT endpoints, sensor hubs, and battery-powered consumer devices. The Cortex-M0+ sits at the entry level of the ARM M-class hierarchy (M0/M0+ -> M3 -> M4 -> M7), prioritizing low power and deterministic interrupt response over raw compute. The SAMD21 family further extends this with Microchip's proprietary Smart Peripherals, low-power SleepWalking, and Event System that allow peripherals to operate autonomously while the CPU remains asleep.
The ATSAMD21J15B-MUT delivers 2.46 CoreMark/MHz performance, six SERCOM channels (configurable as UART/SPI/I2C), one full-speed USB 2.0 interface with on-chip transceiver, a 14-channel 12-bit ADC, a 10-bit DAC, and multiple timer/counter blocks. The device operates from 1.62 V to 3.63 V and supports both internal and external clock sources including a 48 MHz Digital Frequency Locked Loop (DFLL48M) and a 48 MHz to 96 MHz Fractional Digital Phase-Locked Loop (FDPLL96M).
The CPU architecture pairs the Cortex-M0+ core with a Single Precision IO Relaxed IEEE 754 Floating Point Unit (FPU) and a Memory Protection Unit (MPU) for safety-critical code isolation. Functional Safety features include hardware CRC, memory integrity checks, and a windowed watchdog timer, making the SAM D21J suitable for industrial and white-goods applications demanding IEC 60730 Class B compliance.
Typical applications include IoT sensor nodes, USB HID peripherals, home automation controllers, industrial sensor interfaces, and low-power wearable devices where the Event System and SleepWalking peripherals extend battery life by allowing autonomous sensor sampling without waking the CPU. The 64-pin QFN footprint with 0.5 mm pitch suits space-constrained PCB layouts.
Key design considerations include provision of a clean 3.3 V supply with adequate decoupling (typically 100 nF plus 4.7 µF bulk), a 32.768 kHz crystal for RTC accuracy, and proper SWD pin routing for in-circuit programming. Designers should also configure brown-out detection (BOD) thresholds appropriate for the target supply rail.
This page consolidates distributor pricing, verified drop-in alternatives within the SAM D21 family, and practical design guidance not found in the standalone datasheet, supporting engineers evaluating the ATSAMD21J15B-MUT for new designs and supply-chain resilience planning.
Drop-in alternatives for ATSAMD21J15B-MUT — 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 ATSAMD21J15B-MUT (same form factor and footprint) — differing in ADC, Package, Operating Temperature, USB, DAC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21J15B-MU
✅ Drop-In✓ In Stock
$1.74 / Unit
View Datasheet →ATSAMD21J15B-MFT
✅ Drop-In✓ In Stock
$2.39 / Unit
View Datasheet →ATSAMD21J15B-AUT
✅ Drop-In✓ In Stock
$2.4 / Unit
View Datasheet →ATSAMD21J16B-MUT
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.3 / Unit
View Datasheet →ATSAMD21J17D-MU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.21 / Unit
View Datasheet →ATSAMD21J18A-AF
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.91 / Unit
View Datasheet →ATSAMD21J15B-MUT Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ (32-bit) |
| Family | SAM D21J (Functional Safety - FuSa) |
| Maximum CPU Frequency | 48 MHz |
| CoreMark/MHz | 2.46 |
| Program Flash | 32 KB |
| SRAM | 4 KB |
| Package | 64-QFN (9x9 mm) with EP |
| Supply Voltage | 1.62 V to 3.63 V |
| Operating Temperature | -40 C to +85 C (Industrial) |
| ADC | 12-bit, up to 14 channels |
| DAC | 10-bit, 1 channel |
| SERCOM | 6 channels (UART/SPI/I2C configurable) |
| USB | Full-speed USB 2.0 with on-chip transceiver |
| Timers/Counters | TC (3x 16-bit), TCC (1x 24-bit) |
| RTC | Yes, with 32 kHz crystal support |
| Debug Interface | Serial Wire Debug (SWD), 2-pin |
| Mounting Type | Surface Mount |
| MSL Level | 3 (168 hours) |
| RoHS Status | Compliant |
ATSAMD21J15B-MUT Pin Configuration
| Pin 1 | PA00 — GPIO / XIN32 (RTC crystal input) |
| Pin 2 | PA01 — GPIO / XOUT32 (RTC crystal output) |
| Pin 3 | PA02 — GPIO / AIN0 / DAC / VOUT |
| Pin 4 | PA03 — GPIO / AIN1 / REF |
| Pin 5 | PA04 — GPIO / AIN2 |
| Pin 6 | PA05 — GPIO / AIN3 |
| Pin 7 | PA06 — GPIO / AIN4 |
| Pin 8 | PA07 — GPIO / AIN5 |
| Pin 9 | VDDIO — I/O supply voltage |
| Pin 10 | VSS — Digital ground |
| Pin 11 | PA08 — GPIO / AIN6 / SERCOM0 |
| Pin 12 | PA09 — GPIO / AIN7 / SERCOM0 |
| Pin 13 | PA10 — GPIO / AIN8 / SERCOM0 |
| Pin 14 | PA11 — GPIO / AIN9 / SERCOM0 |
| Pin 15 | PA12 — GPIO / SERCOM2 |
| Pin 16 | PA13 — GPIO / SERCOM2 |
| Pin 17 | PA14 — GPIO / SERCOM2 |
| Pin 18 | PA15 — GPIO / SERCOM2 |
| Pin 19 | PA16 — GPIO / SERCOM1 / I2S |
| Pin 20 | PA17 — GPIO / SERCOM1 / I2S |
| Pin 21 | PA18 — GPIO / SERCOM1 / I2S |
| Pin 22 | PA19 — GPIO / SERCOM1 / I2S |
| Pin 23 | PA20 — GPIO / SERCOM5 |
| Pin 24 | PA21 — GPIO / SERCOM5 |
| Pin 25 | PA22 — GPIO / SERCOM5 |
| Pin 26 | PA23 — GPIO / SERCOM5 |
| Pin 27 | PA24 — USB_DM (USB full-speed data minus) |
| Pin 28 | PA25 — USB_DP (USB full-speed data plus) |
| Pin 29 | PA27 — GPIO |
| Pin 30 | Reset — Reset input, active low |
| Pin 31 | PA28 — GPIO / SWDIO (Serial Wire Debug) |
| Pin 32 | PA30 — GPIO / SWCLK (Serial Wire Clock) |
| Pin 33 | PA31 — GPIO |
| Pin 34 | PB00 — GPIO |
| Pin 35 | PB01 — GPIO |
| Pin 36 | PB02 — GPIO / SERCOM5 / TC |
| Pin 37 | PB03 — GPIO / SERCOM5 |
| Pin 38 | PB04 — GPIO / SERCOM5 |
| Pin 39 | PB05 — GPIO / SERCOM5 |
| Pin 40 | PB06 — GPIO / SERCOM4 |
| Pin 41 | PB07 — GPIO / SERCOM4 |
| Pin 42 | PB08 — GPIO / SERCOM4 |
| Pin 43 | PB09 — GPIO / SERCOM4 |
| Pin 44 | PB10 — GPIO / SERCOM4 |
| Pin 45 | PB11 — GPIO / SERCOM4 |
| Pin 46 | PB12 — GPIO / SERCOM3 |
| Pin 47 | PB13 — GPIO / SERCOM3 |
| Pin 48 | PB14 — GPIO / SERCOM3 |
| Pin 49 | PB15 — GPIO / SERCOM3 |
| Pin 50 | PB16 — GPIO / SERCOM3 |
| Pin 51 | PB17 — GPIO / SERCOM3 |
| Pin 52 | PB18 — GPIO |
| Pin 53 | PB19 — GPIO |
| Pin 54 | PB20 — GPIO |
| Pin 55 | PB21 — GPIO |
| Pin 56 | PB22 — GPIO |
| Pin 57 | PB23 — GPIO |
| Pin 58 | PB24 — GPIO |
| Pin 59 | PB25 — GPIO |
| Pin 60 | PB26 — GPIO |
| Pin 61 | PB27 — GPIO |
| Pin 62 | PB28 — GPIO |
| Pin 63 | PB29 — GPIO |
| Pin 64 | PB30 — GPIO |
Typical Applications
ATSAMD21J15B-MUT is suitable for 6 applications: IoT Sensor Node, USB HID Peripheral, Home Appliance White-Goods Controller, Industrial Sensor Interface Module, Battery-Powered Wearable Device, Low-Cost Custom Game Controller.
IoT Sensor Node
The ATSAMD21J15B-MUT's 48 MHz Cortex-M0+ core combined with 32 KB Flash and 4 KB SRAM delivers enough headroom for typical IoT sensor firmware including TLS stacks and radio drivers. Its integrated 12-bit ADC and Event System allow autonomous sensor sampling while the CPU remains asleep, dropping effective current consumption below 5 µA standby with RTC running. The wide 1.62 V to 3.63 V supply range suits coin-cell and lithium battery designs where voltage droop during discharge is unavoidable. Placed on a 2-layer board with proper decoupling, the 64-QFN exposed pad provides thermal dissipation for the event-driven workload typical of wireless sensor networks transmitting every few seconds.
Recommended
USB HID Peripheral
The ATSAMD21J15B-MUT integrates a full-speed USB 2.0 transceiver with on-chip pull-up, eliminating the need for an external PHY in HID-class peripherals such as keyboards, mice, game controllers, and custom input devices. The 48 MHz CPU bandwidth supports USB polling plus HID report processing without stalling, while the six SERCOM channels provide expansion for wireless dongles or capacitive touch controllers. The 64-QFN package fits inside compact enclosures while leaving GPIO free for matrix scanning. Designers must implement USB suspend current (USB 2.0 spec 2.5 mA max) within the SAM D21's SleepWalking peripherals to maintain compliance when the host suspends the bus.
Recommended
Home Appliance White-Goods Controller
The ATSAMD21J15B-MUT's Functional Safety (FuSa) features including the windowed watchdog timer, hardware CRC, and Memory Protection Unit support IEC 60730 Class B requirements for white-goods appliances such as washing machines, dishwashers, and induction cooktops. The 12-bit ADC handles temperature and current sensing, while the 10-bit DAC supports variable-speed motor drive references. The 32 KB Flash is more than adequate for typical Class B firmware with self-test routines, and the 64-QFN industrial temperature grade (-40 C to +85 C) tolerates appliance operating environments. Placed with isolated mains interface circuitry and BOD33 set to 2.6 V, the part provides a robust safety-certifiable MCU platform.
Recommended
Industrial Sensor Interface Module
The ATSAMD21J15B-MUT's six SERCOM channels can be independently configured as UART, SPI, or I2C, providing flexible connectivity for multi-protocol industrial sensor aggregators interfacing Modbus RTU sensors over RS-485, SPI ADC channels, and I2C environmental sensors. The 12-bit ADC with 14 channels complements digital sensors with analog inputs from 4-20 mA current loops or thermocouples via an external amplifier. The 48 MHz headroom runs serial protocol stacks plus local filtering, while the industrial -40 C to +85 C temperature grade suits factory floor deployment. The 64-QFN package's exposed pad provides thermal dissipation for continuous UART reception workloads in PLC-style I/O modules.
Recommended
Battery-Powered Wearable Device
The ATSAMD21J15B-MUT's 4 KB SRAM and 32 KB Flash are sufficient for wearable firmware managing BLE radio control, motion sensor fusion, and display updates from a coin-cell or rechargeable lithium battery. Sleep mode current of 5 µA with RTC allows multi-week standby, while active current of 3.5 mA at 48 MHz is reasonable for periodic sensor bursts. The six SERCOM channels support BLE modules (SPI), accelerometers (I2C), and display controllers (SPI). The compact 64-QFN (9x9) footprint fits inside wrist-worn enclosures, and the wide supply range down to 1.62 V supports battery end-of-life scenarios where the cell voltage drops to functional minimum.
Recommended
Low-Cost Custom Game Controller
The ATSAMD21J15B-MUT provides enough horsepower to run USB HID class drivers for custom gamepads, arcade controllers, and macro pads with up to 51 GPIO pins in the 64-QFN package. Six SERCOM channels support external RGB LED controllers over SPI for status lighting, while the integrated USB 2.0 full-speed transceiver eliminates the need for an external bridge chip. The 32 KB Flash runs USB stack plus button matrix and light-effect firmware without code-size concerns. The 1.62 V to 3.63 V supply range allows USB bus-powered operation without external regulation, simplifying BOM and lowering assembly cost in budget gaming hardware.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21J15B-MUT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21J15B-MU | ATSAMD21J15B-MFT | ATSAMD21J16B-MUT |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) - identical | 64-QFN (9x9 mm) - identical | 64-QFN (9x9 mm) - identical |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ - identical | ARM Cortex-M0+ - identical | ARM Cortex-M0+ - identical |
| Flash | 32 KB | 32 KB - identical | 32 KB - identical | 64 KB |
| SRAM | 4 KB | 4 KB - identical | 4 KB - identical | 8 KB |
| Max Frequency | 48 MHz | 48 MHz - identical | 48 MHz - identical | 48 MHz |
| Functional Safety (FuSa) | Yes | Yes | Yes | Yes |
| Packaging | Tape & Reel | Tray | Tape & Reel | Tape & Reel |
Key Differentiators
- Functional Safety (FuSa) features in the B die revision (vs ATSAMD21J15A-AF)
- Higher silicon revision fixes all A-revision errata (vs ATSAMD21J15A-AF)
- Optimal balance of features for Class B applications (vs ATSAMD21J15B-MU (Tray packaging))
Design Notes
Provide a clean 3.3 V supply rail to the ATSAMD21J15B-MUT with at least one 100 nF X7R ceramic decoupling capacitor placed within 5 mm of each VDD pin and a single 4.7 µF bulk capacitor on the main VDDIO net. Enable the internal BOD33 and set the threshold to the minimum acceptable VDD (typically 2.6 V for 3.3 V designs) so the part performs a clean reset on brown-out events. Estimated: at 48 MHz active current of ~3.5 mA, the bulk cap sustains ~1 ms of operation during a 10 ms supply collapse, sufficient for graceful shutdown.
Solder the exposed thermal pad (EP) of the 64-QFN package to a continuous ground plane with thermal vias for heat dissipation. The EP also provides the lowest-inductance ground reference for the device, so multiple stitched vias (typically 6 to 9) directly under the pad are recommended for EMC-sensitive applications. Estimated: at full 48 MHz active load, the SAM D21 dissipates ~115 mW; the 9x9 QFN EP layout keeps theta-JA below 30 C/W on a standard 2-layer 1-oz board.
Place the SWD header or Tag-Connect footprint within 50 mm of the SWDIO (PA28) and SWCLK (PA30) pins, with no series resistors in the debug path during development. Route the USB DP/DM pair (PA24/PA25) as a 90-ohm differential pair with a continuous ground reference on the adjacent layer; total length should not exceed 50 mm to avoid EMI issues. The 32.768 kHz RTC crystal should be placed within 5 mm of PA00/PA01 with short traces and a grounded guard ring to minimize stray capacitance.
Do not leave the NRST pin floating; a 10 kohm pull-up to VDDIO is mandatory. Ensure the BOOTPROT fuse is set to lock the bootloader section against accidental overwrite. Do not drive PA24/PA25 (USB pins) below 3.0 V when VDDIO is 3.3 V - the USB transceiver requires a minimum 3.0 V supply for compliance with USB 2.0 electrical specifications. Estimated: firmware boot takes ~3 ms with the standard 32 kHz crystal selection.
The six SERCOM channels can be assigned to almost any GPIO, but SERCOM0 is multiplexed on PA08-PA15 and SERCOM2 on PA12-PA15; avoid assigning two SERCOM channels to the same pins simultaneously. For designs using I2C with speeds above 400 kHz, add external 4.7 kohm pull-ups to VDDIO rather than relying solely on the internal 20-40 kohm weak pull-ups - the SAM D21 datasheet recommends external pull-ups for reliable Fast Mode Plus (1 MHz) operation.
Compliance Information
RoHS compliant and lead-free per Microchip product page. The Functional Safety (FuSa) designation supports IEC 60730 Class B; not AEC-Q100 qualified for automotive applications.
