ATSAML21J18A-MUT - 48MHz Cortex-M0+ MCU, 256KB Flash | Microchip
MPN： ATSAML21J18A-MUT ✓ 啟用中ATSAML21J18A-MUT 概覽
What is a Cortex-M0+ microcontroller? A Cortex-M0+ microcontroller is an ARM Holdings 32-bit microcontroller core optimized for the smallest die area and lowest active power, using a 2-stage pipeline and single-cycle I/O port access. Within the hierarchy, the Cortex-M0+ belongs to the ARM Cortex-M family, itself a subset of the ARMv6-M architecture, and the SAM L21 family is Microchip's ultra-low-power derivative. This places the ATSAML21J18A-MUT in the broad category: microcontroller (MCU) -> 32-bit MCU -> ARM Cortex-M MCU -> ultra-low-power MCU -> semiconductor IC.
Key differentiating features include 1.6V to 3.6V supply voltage, integrated full-speed USB 2.0 device with on-chip transceiver, 12-bit 1 MSPS ADC, 10-bit 350 kSPS DAC, four SERCOM channels, six timers, two I2S interfaces, and a PTC (Peripheral Touch Controller) for capacitive touch sensing. The device operates in active, idle, standby, backup, and off sleep modes with wakeup times under 1.5 microseconds, making it ideal for battery-powered applications where microamp sleep currents dominate battery life.
Architecturally, the SAM L21 uses a power-efficient design with separate voltage domains for core and I/O, allowing the I/O bank to remain active while the core is in standby. This dual-bank approach, combined with Microchip's proprietary power-management IP, delivers 35 uA/MHz active current and standby currents around 1.7 uA with full RAM retention, which is competitive in the ultra-low-power MCU class.
Typical applications include battery-powered IoT sensor nodes, wearable fitness bands, smart-home sensor hubs, low-power wireless sensor networks, and capacitive touch human-machine interfaces. Industrial uses include metering, building automation, and remote controls; consumer uses include toys, gaming peripherals, and personal health devices.
Design consideration: when migrating from a SAM D21 part, note that the SAM L21 uses the same SERCOM peripheral but adds a low-power backup domain and a touch controller not present on the SAM D21. Firmware may need to enable the backup domain registers before using RTC or wake-on-touch features.
This page consolidates distributor pricing, drop-in alternatives within the SAM L21 family and across the SAM D21 family, and practical low-power design notes beyond the manufacturer datasheet.
直接替換替代品，適用於 ATSAML21J18A-MUT — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： ATSAML21J18A-MUT （相同外形與佔位） — 差異在於 ADC, DAC, Functional Safety, Package, Mounting Type.
ATSAML21J18B-AUT
✅ 直接替換聯絡詢價
查看資料表 →ATSAMD21J18A-MUT
✅ 直接替換聯絡詢價
查看資料表 →ATSAML21J18A-AUT
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
ATSAML21J18B-MUT
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →ATSAML21J17B-MUT
✅ 直接替換聯絡詢價
查看資料表 →ATSAML21J18A-MUT 最大額定值與電氣特性
| Core | ARM Cortex-M0+ |
| Core Architecture | ARMv6-M |
| Maximum CPU Clock | 48 MHz |
| Flash Memory | 256 KB |
| SRAM | 32 KB |
| Supply Voltage Range | 1.62 V to 3.63 V |
| 封裝 | 64-QFN (9x9 mm) with exposed pad |
| 工作溫度 | -40 C to +85 C |
| ADC | 12-bit, up to 1 MSPS |
| DAC | 10-bit, 350 kSPS |
| USB | USB 2.0 Full-Speed device, on-chip transceiver |
| SERCOM Channels | 6 (configurable as USART, I2C, SPI) |
| Timers | 6 (TC, TCC) |
| Touch Peripheral | PTC (Peripheral Touch Controller), up to 256 channels |
| I/O Pins | Up to 51 |
| RoHS 狀態 | Compliant |
| 安裝類型 | Surface Mount |
| MSL 等級 | MSL3 |
| AEC-Q100 | Not qualified |
| Lead-Free / Halogen-Free | Lead-free; halogen-free status per datasheet |
ATSAML21J18A-MUT 腳位配置
| 腳位 1 | PA00 — GPIO / SERCOM1[0] / ADC[0] |
| 腳位 2 | PA01 — GPIO / SERCOM1[1] / ADC[1] |
| 腳位 3 | PA02 — GPIO / SERCOM0[0] / ADC[2] |
| 腳位 4 | PA03 — GPIO / SERCOM0[1] / ADC[3] / reference |
| 腳位 5 | GND — Ground |
| 腳位 6 | VDDIO — I/O supply voltage |
| 腳位 7 | PA04 — GPIO / SERCOM1[2] / ADC[4] |
| 腳位 8 | PA05 — GPIO / SERCOM1[3] / ADC[5] |
| 腳位 9 | PA06 — GPIO / SERCOM0[2] / ADC[6] |
| 腳位 10 | PA07 — GPIO / SERCOM0[3] / ADC[7] |
| 腳位 11 | PA08 — GPIO / SERCOM2[0] / I2S[0] |
| 腳位 12 | PA09 — GPIO / SERCOM2[1] / I2S[1] |
| 腳位 13 | PA10 — GPIO / SERCOM2[2] / I2S[2] |
| 腳位 14 | PA11 — GPIO / SERCOM2[3] / I2S[3] |
| 腳位 15 | PA12 — GPIO / SERCOM4[0] |
| 腳位 16 | PA13 — GPIO / SERCOM4[1] |
| 腳位 17 | PA14 — GPIO / SERCOM4[2] |
| 腳位 18 | PA15 — GPIO / SERCOM4[3] |
| 腳位 19 | PA16 — GPIO / SERCOM3[0] |
| 腳位 20 | PA17 — GPIO / SERCOM3[1] |
| 腳位 21 | PA18 — GPIO / SERCOM3[2] |
| 腳位 22 | PA19 — GPIO / SERCOM3[3] |
| 腳位 23 | PA20 — GPIO / SERCOM5[0] |
| 腳位 24 | PA21 — GPIO / SERCOM5[1] |
| 腳位 25 | PA22 — GPIO / SERCOM5[2] |
| 腳位 26 | PA23 — GPIO / SERCOM5[3] |
| 腳位 27 | PA24 — GPIO / SERCOM5[0] alt |
| 腳位 28 | PA25 — GPIO / SERCOM5[1] alt |
| 腳位 29 | PB00 — GPIO / SERCOM5[2] alt |
| 腳位 30 | PB01 — GPIO / SERCOM5[3] alt |
| 腳位 31 | PB02 — GPIO / SERCOM5[0] alt |
| 腳位 32 | PB03 — GPIO / SERCOM5[1] alt |
| 腳位 33 | PB04 — GPIO / SERCOM5[2] alt |
| 腳位 34 | PB05 — GPIO / SERCOM5[3] alt |
| 腳位 35 | PB06 — GPIO / SERCOM5[0] |
| 腳位 36 | PB07 — GPIO / SERCOM5[1] |
| 腳位 37 | PB08 — GPIO / SERCOM5[2] |
| 腳位 38 | PB09 — GPIO / SERCOM5[3] |
| 腳位 39 | PB10 — GPIO / SERCOM5[0] alt |
| 腳位 40 | PB11 — GPIO / SERCOM5[1] alt |
| 腳位 41 | PB12 — GPIO / SERCOM5[2] alt |
| 腳位 42 | PB13 — GPIO / SERCOM5[3] alt |
| 腳位 43 | PB14 — GPIO / SERCOM5[0] |
| 腳位 44 | PB15 — GPIO / SERCOM5[1] |
| 腳位 45 | PB16 — GPIO / SERCOM5[2] |
| 腳位 46 | PB17 — GPIO / SERCOM5[3] |
| 腳位 47 | PC00 — GPIO |
| 腳位 48 | PC01 — GPIO |
| 腳位 49 | PC02 — GPIO |
| 腳位 50 | PC03 — GPIO |
| 腳位 51 | PC04 — GPIO |
| 腳位 52 | PC05 — GPIO |
| 腳位 53 | PC06 — GPIO |
| 腳位 54 | PC07 — GPIO |
| 腳位 55 | VDDANA — Analog supply voltage |
| 腳位 56 | GNDANA — Analog ground |
| 腳位 57 | VDDIO — I/O supply voltage |
| 腳位 58 | GND — Ground |
| 腳位 59 | VSW — Buck/LDO switch node |
| 腳位 60 | VBAT — Backup battery supply |
| 腳位 61 | RESETn — Reset input, active low |
| 腳位 62 | SWCLK — SWD clock |
| 腳位 63 | SWDIO — SWD data |
| 腳位 64 | NC — Not connected (per datasheet) |
典型應用
ATSAML21J18A-MUT 適用於 7 應用s: Battery-Powered IoT Sensor Node, Wearable Fitness / Health Band, Smart Home Sensor Hub, Capacitive Touch User Interface, Industrial Metering Endpoints, Remote Control / Gaming Peripheral, USB-Powered Embedded Device.
Battery-Powered IoT Sensor Node
The ATSAML21J18A-MUT suits battery-powered IoT sensor nodes because of its 1.7 uA standby current with full RAM retention and 256 KB Flash for over-the-air (OTA) firmware updates. Its six SERCOM channels allow simultaneous SPI sensor, I2C sensor, and UART debug interfaces without external mux ICs. The 48 MHz Cortex-M0+ core handles sensor fusion at 100 Hz sample rates while consuming under 35 uA/MHz active. Powered from a CR2032 coin cell (3 V, 220 mAh), typical duty-cycled designs achieve 3-5 year battery life.
推薦
Wearable Fitness / Health Band
The ATSAML21J18A-MUT is well suited for wearable fitness bands due to its integrated 12-bit 1 MSPS ADC for heart-rate sensor signal acquisition, USB 2.0 Full-Speed for charging and data sync, and ultra-low standby current that preserves battery during idle wear periods. The integrated PTC touch controller supports swipe/tap input on flexible PCB overlays without mechanical buttons. The 64-QFN 9x9 mm package fits into 20 mm wide wristband modules, and 32 KB SRAM buffers 24 hours of step-count and accelerometer data.
推薦
Smart Home Sensor Hub
For smart-home sensor hubs, the ATSAML21J18A-MUT provides six SERCOM channels to connect multiple radios and sensors (Zigbee, BLE, temperature, humidity, motion), 256 KB Flash for protocol stack plus application logic, and a Cortex-M0+ core that runs BLE HCI or simple proprietary RF stacks. USB Full-Speed enables commissioning via a USB-C port. With 1.6 V to 3.6 V supply, the part runs directly from 2x AA alkaline batteries or from a USB 5 V rail through an LDO, simplifying BOM.
推薦
Capacitive Touch User Interface
The ATSAML21J18A-MUT's integrated Peripheral Touch Controller (PTC) supports up to 256 capacitive touch channels with hardware-driven acquisition, freeing the Cortex-M0+ core from polling overhead. This makes it ideal for appliance control panels, induction cooktops, and industrial HMI touchscreens. Combined with 256 KB Flash for touch firmware plus display drivers, and 1 MSPS ADC for backlight dimming, the part covers the entire HMI subsystem in a single QFN.
推薦
Industrial Metering Endpoints
The ATSAML21J18A-MUT fits battery-powered industrial metering endpoints (water, gas, electricity) that demand 10+ year battery life and remote firmware updates. Its 1.7 uA standby current minimizes quiescent drain, while 256 KB Flash accommodates segmented OTA bootloaders (application + dual-bank update image). The 12-bit ADC with internal reference meets metering accuracy class 1.0 in single-point calibration, and the USB port supports factory calibration and field diagnostics.
推薦
Remote Control / Gaming Peripheral
The ATSAML21J18A-MUT suits battery-powered remote controls and gaming peripherals due to its PTC for touch-sensitive surfaces, USB Full-Speed for wired connectivity when docked, and low active power allowing 100+ hours of continuous IR / Bluetooth operation from two AAA cells. The 32 KB SRAM handles HID report queues and on-the-fly macro programming. Microchip's MPLAB Harmony framework provides ready HID class drivers, shortening development cycles for consumer gaming accessories.
推薦
USB-Powered Embedded Device
The ATSAML21J18A-MUT integrates a USB 2.0 Full-Speed device controller with on-chip transceiver, eliminating the external PHY and reducing BOM cost for USB peripherals such as data loggers, programmers, and HID-class accessories. Operating from 1.62 V to 3.63 V, the device can run directly from USB VBUS through a 3.3 V LDO. The 256 KB Flash holds USB stacks plus application code, and the six SERCOM channels connect to sensors, displays, or storage.
推薦
推薦產品摘要
工程參考資料，適用於 ATSAML21J18A-MUT — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | ATSAML21J18B-AUT | ATSAMD21J18A-MUT | ATSAML21J18A-AUT | ATSAML21J18B-MUT | ATSAML21J17B-MUT |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-QFN (9x9) | 64-QFN (9x9) | 64-QFN (9x9) | 64-QFN (9x9) | 64-QFN (9x9) | 64-QFN (9x9) |
| Core | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ |
| Maximum CPU Clock | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Flash Memory | 256 KB | 256 KB | 256 KB | 256 KB | 256 KB | 128 KB |
| SRAM | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB | 16 KB |
| Supply Voltage Range | 1.62 V to 3.63 V | 1.62 V to 3.63 V | 1.62 V to 3.63 V | 1.62 V to 3.63 V | 1.62 V to 3.63 V | 1.62 V to 3.63 V |
| Touch Peripheral (PTC) | Yes (up to 256 channels) | Yes (up to 256 channels) | No PTC peripheral | Yes (up to 256 channels) | Yes (up to 256 channels) | Yes (up to 256 channels) |
| USB Full-Speed | Yes (on-chip transceiver) | Yes (on-chip transceiver) | Yes (on-chip transceiver) | Yes (on-chip transceiver) | Yes (on-chip transceiver) | Yes (on-chip transceiver) |
主要差異化特點
- Integrated Peripheral Touch Controller (PTC) with up to 256 channels (對比ATSAMD21J18A-MUT)
- Lower standby current with full RAM retention (對比ATSAMD21J18A-MUT)
- Backup power domain with RTC (對比ATSAMD21J18A-MUT)
- Same 64-QFN footprint as ATSAMD21J18A-MUT for PCB reuse (對比ATSAMD21J18A-MUT)
設計說明
To minimize standby current on the ATSAML21J18A-MUT, configure unused GPIO as analog (input disable, no pull-up) and disable unneeded peripherals via the PMUX / APBCMASK registers before entering STANDBY sleep mode. Per the SAM L21 datasheet, leaving a peripheral clock enabled can add 50-200 uA of leakage. For coin-cell designs, also route the VBAT pin to the same supply as VDD to avoid backup-domain switching transients during battery insertion.
Estimated: At maximum CPU load (48 MHz, all peripherals active), the ATSAML21J18A-MUT consumes approximately 35 uA/MHz x 48 MHz = 1.68 mA active current. With a 3.3 V supply, that is 5.5 mW power dissipation. The 64-QFN exposed pad should be soldered to a continuous ground copper pour at least 25 mm^2 to keep junction temperature rise below 5 C above ambient (theta_JA approximately 20-25 C/W on a 4-layer JEDEC test board). No external heatsink is required.
Place a 1 uF ceramic decoupling capacitor within 3 mm of each VDDIO pin and a 4.7 uF bulk capacitor near the exposed thermal pad for the ATSAML21J18A-MUT. According to the SAM L21 layout guidelines, separate analog and digital ground planes should be stitched together at a single point under the GNDANA pin. Route the SWD clock and data traces as a length-matched differential pair under 50 mm to avoid debugger communication errors at high debug clock rates.
A common pitfall when migrating firmware from ATSAMD21J18A to ATSAML21J18A-MUT is forgetting to enable the backup power domain in the SUPC (Supply Controller) register before configuring the RTC. The SAM D21 has no backup domain, so the SUPC register write sequence is new to SAM L21 code. If RTC alarms do not fire after sleep, check that SUPC was initialized correctly. Also, the SAM L21 ADC requires an extra channel-impedance calibration step at temperatures below -20 C.
合規資訊
RoHS and lead-free compliant per Microchip product page. AEC-Q100 not qualified (industrial grade only); for automotive applications consider ATSAMxE variants. Halogen-free status not explicitly stated in retrieved data.
