ATSAMD21J18A-AFT - 32-bit Cortex-M0+ MCU, 256KB Flash, 64-TQFP | Microchip
MPN: ATSAMD21J18A-AFT ✓ Hoạt độngATSAMD21J18A-AFT Tóm tắt
A microcontroller (MCU) is a single-chip computer containing a CPU core, program and data memory, peripherals, and I/O. The Cortex-M0+ core from ARM is the smallest and most energy-efficient ARM core, optimized for deterministic embedded control and low active power. The SAM D21J family extends this core with rich peripherals including SERCOM, ADC, DAC, and event system, placing the MCU in the broader hierarchy: microcontroller -> embedded processor -> semiconductor device.
Key features of the ATSAMD21J18A-AFT include 6 SERCOM serial communication interfaces (each configurable as UART/SPI/I2C), a 12-bit 1 MSPS ADC with up to 20 channels, a 10-bit DAC, full-speed USB device/host, and a 2-channel DMAC for low-overhead data movement. The device supports sleepwalking peripherals and idle/standby modes that drop quiescent current to single-digit microamps, enabling years of battery life in sensor applications.
The ATSAMD21J18A-AFT is functionally safety-capable (FuSa) and integrates the ARM Cortex-M0+ core with single-cycle multiplier, hardware divide, and a Nested Vectored Interrupt Controller (NVIC). A 32-channel event system allows peripherals to trigger one another without CPU intervention, reducing wake latency and energy. The device also includes a segmented LCD controller variant in the family, but the -J18A part focuses on connectivity-rich general-purpose applications.
Typical applications include home automation gateways, IoT sensor nodes with USB connectivity, industrial metering, low-end consumer HMI, smart thermostats, and wearable fitness devices. The extended -40C to +125C temperature range supports outdoor and industrial enclosures.
Designers should plan PCB layout carefully: place the 0.1 uF decoupling capacitor within 2 mm of each VDD pin, provide a solid ground pour under the device, and route the D+/D- lines as a 90-ohm differential pair with no stubs. The internal voltage regulator requires both a VDDCORE and VDDIO supply pin to be decoupled.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found in the manufacturer datasheet alone.
Bộ thay thế dễ dàng lắp đặt cho ATSAMD21J18A-AFT — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với ATSAMD21J18A-AFT (cùng hình factor và footprint) — khác nhau ở ADC, Core, DAC, USB, Operating Temperature.
ATSAMD21J18A-AU
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ATSAMD21J18A-AUT
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ATSAMD21J17A-AUT
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ATSAMD21J16B-AU
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ATSAMD21J18A-AFT Tỷ lệ tối đa & tính chất điện
| Core | ARM Cortex-M0+ (32-bit) |
| Family | SAM D21J |
| Maximum CPU Frequency | 48 MHz |
| Flash Memory | 256 KB |
| SRAM | 32 KB |
| Supply Voltage (VDD) | 1.62 V to 3.63 V |
| Nhiệt độ hoạt động | -40C to +125C |
| Hộp | 64-pin TQFP (10x10 mm) |
| Kiểu lắp đặt | Surface Mount (SMD/SMT) |
| I/O Pins | Up to 52 |
| SERCOM | 6 (each configurable as UART/SPI/I2C) |
| ADC | 12-bit, up to 20 channels, 1 MSPS |
| DAC | 10-bit, 1 channel |
| USB | Full-speed USB 2.0 device and host |
| DMAC | 12 channels |
| Functional Safety | FuSa-capable |
| Trạng thái RoHS | Compliant (Green) |
Cấu hình chân ATSAMD21J18A-AFT
| Chân 1 | PA00 — General-purpose I/O / XIN32 |
| Chân 2 | PA01 — General-purpose I/O / XOUT32 |
| Chân 3 | PA02 — General-purpose I/O / AIN0 |
| Chân 4 | PA03 — General-purpose I/O / AIN1 / VREFA |
| Chân 5 | PA04 — General-purpose I/O / AIN2 |
| Chân 6 | PA05 — General-purpose I/O / AIN3 |
| Chân 7 | PA06 — General-purpose I/O / AIN4 |
| Chân 8 | PA07 — General-purpose I/O / AIN5 |
| Chân 9 | VDD — Digital supply voltage |
| Chân 10 | GND — Ground |
| Chân 11 | PA08 — General-purpose I/O / NMI / AIN6 |
| Chân 12 | PA09 — General-purpose I/O / AIN7 |
| Chân 13 | PA10 — General-purpose I/O / AIN8 |
| Chân 14 | PA11 — General-purpose I/O / AIN9 |
| Chân 15 | PA12 — General-purpose I/O |
| Chân 16 | PA13 — General-purpose I/O |
| Chân 17 | PA14 — General-purpose I/O |
| Chân 18 | PA15 — General-purpose I/O |
| Chân 19 | PA16 — General-purpose I/O / I2S_SDI0 |
| Chân 20 | PA17 — General-purpose I/O / I2S_SDO0 |
| Chân 21 | PA18 — General-purpose I/O / I2S_FS0 |
| Chân 22 | PA19 — General-purpose I/O / I2S_SCK0 |
| Chân 23 | PA20 — General-purpose I/O |
| Chân 24 | PA21 — General-purpose I/O / AIN10 |
| Chân 25 | PA22 — General-purpose I/O / AIN11 |
| Chân 26 | PA23 — General-purpose I/O |
| Chân 27 | PA24 — General-purpose I/O / USB_DM |
| Chân 28 | PA25 — General-purpose I/O / USB_DP |
| Chân 29 | PA26 — General-purpose I/O |
| Chân 30 | PA27 — General-purpose I/O |
| Chân 31 | PA28 — General-purpose I/O |
| Chân 32 | PA29 — General-purpose I/O |
| Chân 33 | PA30 — General-purpose I/O / SWCLK |
| Chân 34 | PA31 — General-purpose I/O / SWDIO |
| Chân 35 | PB00 — General-purpose I/O |
| Chân 36 | PB01 — General-purpose I/O |
| Chân 37 | PB02 — General-purpose I/O / AIN12 |
| Chân 38 | PB03 — General-purpose I/O / AIN13 |
| Chân 39 | PB04 — General-purpose I/O / AIN14 |
| Chân 40 | PB05 — General-purpose I/O / AIN15 |
| Chân 41 | PB06 — General-purpose I/O |
| Chân 42 | PB07 — General-purpose I/O |
| Chân 43 | PB08 — General-purpose I/O |
| Chân 44 | PB09 — General-purpose I/O |
| Chân 45 | PB10 — General-purpose I/O |
| Chân 46 | PB11 — General-purpose I/O |
| Chân 47 | PB12 — General-purpose I/O |
| Chân 48 | PB13 — General-purpose I/O |
| Chân 49 | PB14 — General-purpose I/O |
| Chân 50 | PB15 — General-purpose I/O |
| Chân 51 | PB16 — General-purpose I/O |
| Chân 52 | PB17 — General-purpose I/O |
| Chân 53 | PB18 — General-purpose I/O |
| Chân 54 | PB19 — General-purpose I/O |
| Chân 55 | PB20 — General-purpose I/O |
| Chân 56 | PB21 — General-purpose I/O |
| Chân 57 | VDDIO — I/O supply voltage |
| Chân 58 | GND — Ground |
| Chân 59 | VDDCORE — Internal core voltage output (1.2V) |
| Chân 60 | GND — Ground |
| Chân 61 | VDDIN — Voltage regulator input |
| Chân 62 | RESETN — Reset input (active low) |
| Chân 63 | VREFP — ADC reference voltage positive |
| Chân 64 | VREFN — ADC reference voltage negative |
Ứng dụng tiêu biểu
ATSAMD21J18A-AFT phù hợp cho 6 Áp dụngs: Home Automation Gateway, IoT Sensor Node with USB, Industrial Metering, Consumer HMI with Display, Wearable Fitness Device, Smart Agriculture Sensor.
Home Automation Gateway
The ATSAMD21J18A-AFT fits home automation gateways by combining 256 KB Flash for Zigbee/Wi-Fi stack plus application logic with full-speed USB for dongle connectivity. Its six SERCOM ports drive multiple wireless co-processor UARTs simultaneously while the 12-bit ADC reads analog sensors. The 48 MHz Cortex-M0+ executes protocol stacks with deterministic latency, and the -40C to +125C range supports indoor attic installations. Sleepwalking peripherals and standby current under 5 uA keep always-on power budgets low for AC-powered but energy-rated designs.
Được đề xuất
IoT Sensor Node with USB
The ATSAMD21J18A-AFT is ideal for USB-connected IoT sensor nodes because its on-chip full-speed USB 2.0 device port eliminates external PHY chips. The 256 KB Flash stores application plus USB stack plus sensor drivers, while 32 KB SRAM buffers high-rate ADC samples. The 12-channel DMAC moves data without CPU wake-up, extending battery life. The 1.62-3.63 V supply range supports direct Li-ion or 2xAA battery operation with internal LDO regulation. Six SERCOM connect I2C sensors, SPI displays, and UART debug simultaneously.
Được đề xuất
Industrial Metering
Industrial metering designs use the ATSAMD21J18A-AFT because its 12-bit 1 MSPS ADC captures fast current/voltage transients while the Cortex-M0+ runs RMS and power-factor calculations in real time. The extended -40C to +125C temperature range handles outdoor cabinet environments, and the 64-pin TQFP package with 52 I/O drives segmented displays, optocouplers, and isolated serial links. The on-chip event system triggers ADC conversions from timer compare matches without CPU latency, ensuring sample-accurate metering across load variations.
Được đề xuất
Consumer HMI with Display
The ATSAMD21J18A-AFT drives consumer human-machine interfaces such as smart thermostats and appliance front panels using its six SERCOM channels to run SPI TFT displays plus I2C touch controllers plus UART wireless modules. The DAC outputs audio cues while the 32 KB SRAM buffers frame updates. The 256 KB Flash holds a full graphics library plus wireless stack. The 48 MHz Cortex-M0+ delivers responsive UI animations and the extended temperature grade tolerates kitchen or bathroom installations where humidity and heat stress components.
Được đề xuất
Wearable Fitness Device
Wearable fitness devices leverage the ATSAMD21J18A-AFT low-power standby modes that drop current below 5 uA while retaining RTC and RAM. The 12-bit ADC reads heart-rate and SpO2 photodiode signals, six SERCOM connect BLE modules, IMUs, and flash storage. The 48 MHz core handles Bluetooth Low Energy link-layer encryption while event-system wake-ups minimize active time. The 1.62 V minimum supply supports single-cell Li-ion or coin-cell designs, and the -40C to +125C rating covers skin contact and outdoor exercise conditions.
Được đề xuất
Smart Agriculture Sensor
The ATSAMD21J18A-AFT supports smart agriculture sensor endpoints with its extended -40C to +125C temperature range for outdoor field installations exposed to direct sun and frost. The 12-bit ADC reads soil moisture, temperature, and pH probes; SERCOM interfaces drive LoRa or Sub-GHz radio modules. Sleepwalking SERCOM and event system allow years of battery life on a single Li-SOCl2 cell. The 256 KB Flash stores sensor fusion algorithms and over-the-air update bootloaders. The 64-pin TQFP package simplifies hand-rework for prototyping.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho ATSAMD21J18A-AFT — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | ATSAMD21J18A-AU | ATSAMD21J18A-AUT | ATSAMD21J17A-AU | ATSAMD21J16B-AU |
|---|---|---|---|---|---|
| Brand | Microchip Technology | 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 | 64-pin TQFP (10x10 mm) - same |
| Flash Memory | 256 KB | 256 KB (same) | 256 KB (same) | 128 KB (-50%) | 64 KB (-75%) |
| SRAM | 32 KB | 32 KB (same) | 32 KB (same) | 16 KB (-50%) | 8 KB (-75%) |
| Operating Temperature | -40C to +125C | -40C to +85C | -40C to +125C (same) | -40C to +85C | -40C to +85C |
| CPU Frequency | 48 MHz | 48 MHz (same) | 48 MHz (same) | 48 MHz (same) | 48 MHz (same) |
| USB | Full-speed USB 2.0 | Full-speed USB 2.0 (same) | Full-speed USB 2.0 (same) | Full-speed USB 2.0 (same) | Full-speed USB 2.0 (same) |
| SERCOM | 6 | 6 (same) | 6 (same) | 6 (same) | 6 (same) |
Bảo phân biệt quan trọng
- Extended industrial temperature grade -40C to +125C (vsATSAMD21J18A-AU)
- Full 256 KB Flash vs reduced variants in same family (vsATSAMD21J16B-AU)
- Functional Safety (FuSa) capability (vsATSAMC21J18A)
- Six SERCOM channels vs fewer in smaller packages (vsATSAMD21E18A-AFT)
Ghi chú thiết kế
The ATSAMD21J18A-AFT requires both VDDIN (regulator input) and VDDIO (I/O supply) to be tied together through ferrite beads or directly bridged, with a 1 uF + 0.1 uF decoupling pair within 2 mm of each pin. According to the SAM D21 datasheet, VDDIN is the source for the internal 1.2 V LDO that supplies VDDCORE; bypassing VDDIN with at least 4.7 uF bulk capacitance prevents LDO dropout during ADC bursts. Estimated: a 100 mA peak ADC + core load at 3.3 V implies 330 mW peak dissipation inside the chip.
Route the USB D+ and D- pins (PA24/PA25) as a 90-ohm differential pair with no stubs and no vias within 5 mm of the device. According to the SAM D21 datasheet, the USB full-speed transceiver is integrated and does not require an external PHY, but PCB trace impedance must match the USB 2.0 spec. Place a 10 uF + 0.1 uF cap on VBUS if the design is bus-powered. Maintain a continuous ground reference plane under the pair to control common-mode impedance.
Do not configure the BOOTPROT fuse to lock the device without first programming a valid application - a misconfigured lockbit can brick the part and require a 12V high-voltage programmer to recover. According to Microchip errata documents, early SAM D21 silicon revisions had a known USB suspend behavior requiring a firmware workaround in revision A and B; verify silicon revision via the DSU DID register before production. Always set the NVMCTRL fuse to map the bootloader at 0x00000000 BEFORE enabling protected boot.
Place the 32.768 kHz crystal as close as possible to pins XIN32/XOUT32 (PA00/PA01) with short, symmetric traces and a guard ring tied to analog ground. According to the SAM D21 datasheet, stray capacitance above 5 pF on these pins detunes the crystal load and degrades RTC accuracy below 20 ppm. Estimated: a 4 mm trace plus a 2 pF pad capacitance gives 1.5 pF total stray, well within margin for an external load capacitor of 12.5 pF. Shield the crystal from digital signals crossing nearby.
Thông tin tuân thủ
Green / lead-free / RoHS compliant per Microchip ordering information. Not AEC-Q100 qualified; for automotive designs, look at SAM DA1 family.
