ATSAMD20J18A-CU - 48MHz Cortex-M0+ MCU 256KB Flash | Microchip
MPN: ATSAMD20J18A-CU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.1 | $5.10 |
| 10 | $4.58 | $45.80 |
| 100 | $4.05 | $405.00 |
| 500 | $3.62 | $1,810.00 |
| 1,000 | $3.2 | $3,200.00 |
ATSAMD20J18A-CU Overview
A microcontroller (MCU) is an integrated circuit that combines a processor core, program memory (Flash), working memory (SRAM), and a rich set of peripherals on a single die. The Cortex-M0+ class of MCUs represents the most energy-efficient tier of the ARM Cortex-M family, optimized for deterministic interrupt-driven workloads and ultra-low standby power. Within Microchip's portfolio, the ATSAMD20J18 belongs to the SAM D20 family of microcontrollers, sitting in the broader category of 32-bit flash MCUs under the Microchip SMART ARM-based product line. The part is pin-compatible across the SAM D20 series, enabling identical PCB layouts for variants with differing Flash and SRAM sizes.
Key features of the ATSAMD20J18A-CU include an integrated 12-bit ADC with up to 20 channels, a 10-bit DAC, a 256-channel Peripheral Touch Controller (PTC), a full-speed USB 2.0 device interface, multiple SERCOM (serial communication) modules configurable as UART, SPI, or I2C, and a 32-bit Real-Time Clock (RTC). It also provides six 16-bit Timer/Counters, an Event System for inter-peripheral signaling without CPU intervention, and a comprehensive clock management unit with on-chip PLLs and oscillators.
Architecturally, the ATSAMD20J18A-CU is built on a low-leakage CMOS process and integrates a high-performance 32-bit core with single-cycle I/O access, hardware multiply, and a Nested Vectored Interrupt Controller (NVIC). The 2.46 CoreMark/MHz figure confirms efficient Thumb-2 instruction execution, and the wide 1.62 V to 3.63 V operating range allows direct connection to single-cell Li-ion or 3.3 V regulated rails.
Typical applications include low-power wireless sensor nodes, smart metering, home automation controllers, USB Human Interface Devices (HIDs), industrial control panels, and consumer electronics with capacitive touch user interfaces. The rich peripheral mix enables single-chip implementations of bridge, HMI, and data-acquisition products.
Designers should plan for the SERCOM peripheral mapping during firmware architecture, since each SERCOM instance can be routed to a specific set of pads. Decoupling must include a 100 nF cap per VDD pin plus a bulk 4.7 uF capacitor placed close to the package. For USB applications, the DP/DM traces require 90 ohm differential impedance and a precision 1.0 uF USB transceiver bypass capacitor.
This page synthesizes distributor pricing, drop-in alternatives within the SAM D20 family and from competing Cortex-M0+ families, and practical design notes that go beyond the manufacturer datasheet to accelerate your schematic capture and PCB layout decisions.
Drop-in alternatives for ATSAMD20J18A-CU — 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 ATSAMD20J18A-CU (same form factor and footprint) — differing in ADC, Package, Operating Temperature, USB, SRAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD20J17A-CNT
✅ Drop-In✓ In Stock
$2.61 / Unit
View Datasheet →ATSAMD20J16A-CNT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD20J15A-CU
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →ATSAMD21J18A-CU
✅ Drop-In✓ In Stock
$2.52 / Unit
View Datasheet →ATSAMD20J18A-MU
✅ Drop-In✓ In Stock
$2.69 / Unit
View Datasheet →ATSAMD20J18A-CU Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ (32-bit) |
| Maximum CPU Frequency | 48 MHz |
| Flash Memory | 256 KB |
| SRAM | 32 KB |
| Operating Voltage Range | 1.62 V to 3.63 V |
| Package | 64-ball UFBGA, 5x5 mm |
| ADC | 12-bit, up to 20 channels |
| DAC | 10-bit |
| Touch Controller (PTC) | 256 channels |
| USB | Full-Speed USB 2.0 Device |
| Serial Communication | SERCOM x6 (UART/SPI/I2C) |
| Timers | 16-bit TC x6 |
| Operating Temperature | -40C to +85C (industrial) |
| Mounting Type | Surface Mount |
| CoreMark Score | 2.46 CoreMark/MHz |
| RoHS Status | Compliant |
ATSAMD20J18A-CU Pin Configuration
| Pin A1 | VDDIO — Digital I/O supply voltage |
| Pin A2 | PA02 — GPIO / analog input |
| Pin A3 | PA03 — GPIO / analog input |
| Pin A4 | PA04 — GPIO / analog input |
| Pin A5 | PA05 — GPIO / analog input |
| Pin A6 | PA06 — GPIO / analog input |
| Pin A7 | PA07 — GPIO / analog input |
| Pin A8 | VDDANA — Analog supply voltage |
| Pin B1 | PA08 — GPIO / SERCOM / TC |
| Pin B2 | PA09 — GPIO / SERCOM / TC |
| Pin B3 | PA10 — GPIO / SERCOM / TC |
| Pin B4 | PA11 — GPIO / SERCOM |
| Pin B5 | PA14 — GPIO / SERCOM / TC |
| Pin B6 | PA15 — GPIO / SERCOM / TC |
| Pin B7 | PA16 — GPIO / SERCOM |
| Pin B8 | GND — Ground |
| Pin C1 | PA17 — GPIO / SERCOM |
| Pin C2 | PA18 — GPIO / SERCOM / TC |
| Pin C3 | PA19 — GPIO / SERCOM / TC |
| Pin C4 | PA20 — GPIO / SERCOM / TC |
| Pin C5 | PA21 — GPIO / SERCOM / TC |
| Pin C6 | PA22 — GPIO / SERCOM / TC |
| Pin C7 | PA23 — GPIO / SERCOM / TC |
| Pin C8 | PA24 — GPIO / USB SOF |
| Pin D1 | PA25 — GPIO / SERCOM / USB_NEG |
| Pin D2 | PA27 — GPIO / USB_POS |
| Pin D3 | PA28 — GPIO / Reset input |
| Pin D4 | GND — Ground |
| Pin D5 | PA30 — GPIO / SWCLK |
| Pin D6 | PA31 — GPIO / SWDIO |
| Pin D7 | PB02 — GPIO / SERCOM / ADC |
| Pin D8 | PB03 — GPIO / SERCOM / ADC |
| Pin E1 | PB04 — GPIO / SERCOM / ADC |
| Pin E2 | PB05 — GPIO / SERCOM / ADC |
| Pin E3 | PB06 — GPIO / SERCOM / ADC |
| Pin E4 | PB07 — GPIO / SERCOM / ADC |
| Pin E5 | PB08 — GPIO / SERCOM / ADC |
| Pin E6 | PB09 — GPIO / SERCOM / ADC |
| Pin E7 | PB10 — GPIO / SERCOM / ADC |
| Pin E8 | PB11 — GPIO / SERCOM / ADC |
| Pin F1 | PB12 — GPIO / SERCOM / TC |
| Pin F2 | PB13 — GPIO / SERCOM / TC |
| Pin F3 | PB14 — GPIO / SERCOM / TC |
| Pin F4 | PB15 — GPIO / SERCOM / TC |
| Pin F5 | PB16 — GPIO / SERCOM / TC |
| Pin F6 | PB17 — GPIO / SERCOM / TC |
| Pin F7 | PB18 — GPIO / SERCOM / TC |
| Pin F8 | PB19 — GPIO / SERCOM / TC |
| Pin G1 | PB20 — GPIO / SERCOM / TC |
| Pin G2 | PB21 — GPIO / SERCOM / TC |
| Pin G3 | PB22 — GPIO / SERCOM |
| Pin G4 | PB23 — GPIO / SERCOM |
| Pin G5 | PB24 — GPIO / SERCOM |
| Pin G6 | PB25 — GPIO / SERCOM |
| Pin G7 | PB26 — GPIO / SERCOM |
| Pin G8 | PB27 — GPIO / SERCOM |
| Pin H1 | PB28 — GPIO / SERCOM |
| Pin H2 | PB29 — GPIO / SERCOM |
| Pin H3 | PB30 — GPIO / SERCOM / TC |
| Pin H4 | PB31 — GPIO / SERCOM / TC |
| Pin H5 | VDDIO — Digital I/O supply voltage |
| Pin H6 | GND — Ground |
| Pin H7 | XIN — Crystal oscillator input |
| Pin H8 | XOUT — Crystal oscillator output |
Typical Applications
ATSAMD20J18A-CU is suitable for 7 applications: Low-Power Wireless Sensor Node, Smart Home Automation Controller, USB Human Interface Device (HID), Capacitive Touch HMI Panel, Industrial Metering and Data Acquisition, Portable Consumer Wearable Device, Battery-Powered IoT Edge Node.
Low-Power Wireless Sensor Node
The ATSAMD20J18A-CU is well suited for battery-powered wireless sensor nodes because its Cortex-M0+ core delivers 2.46 CoreMark/MHz while drawing as little as 70 uA/MHz active, and deep-sleep current stays below 1 uA with RTC retention. The 256 KB Flash comfortably accommodates protocol stacks such as LoRaWAN, Zigbee, or BLE application layers alongside sensor drivers and OTA update logic. The 32 KB SRAM supports multi-channel sensor buffering and radio packet handling. Designers pair the MCU with sub-GHz transceivers or BLE SoCs through SERCOM-configurable UART or SPI interfaces, leveraging the 1.62 V to 3.63 V supply range to run directly from a single CR2032 or Li-ion cell.
Recommended
Smart Home Automation Controller
In smart home automation hubs and edge controllers, the ATSAMD20J18A-CU's 256 KB Flash and 32 KB SRAM enable on-device logic for sensor fusion, rule engines, and Matter or Zigbee coordination without external memory. The 12-bit ADC with up to 20 channels accepts inputs from multiple analog sensors (temperature, humidity, light, occupancy), while the 256-channel Peripheral Touch Controller allows the same chip to drive capacitive touch keypads or sliders. USB device support simplifies commissioning and firmware update via standard USB-C ports, and the wide 1.62 V to 3.63 V supply tolerates wall-adapter ripple and battery backup transitions seamlessly.
Recommended
USB Human Interface Device (HID)
The ATSAMD20J18A-CU's integrated full-speed USB 2.0 device port makes it a cost-effective choice for USB HID peripherals such as keyboards, mice, programmable keypads, and custom control surfaces. The 48 MHz Cortex-M0+ core handles HID class drivers, debounce algorithms, and RGB lighting effects concurrently, while the 256 KB Flash holds USB stacks, HID report descriptors, and application firmware. The six 16-bit Timer/Counter channels manage key scanning matrices, and the Event System routes GPIO interrupts to the CPU without software overhead. Industrial temperature grade and 1.62 V to 3.63 V operation suit both office and rugged deployments.
Recommended
Capacitive Touch HMI Panel
The ATSAMD20J18A-CU integrates Microchip's Peripheral Touch Controller (PTC) with support for up to 256 touch channels, enabling direct drive of large capacitive touch panels without an external touch IC. The 12-bit ADC and on-chip hardware PTC scan engine handle self-capacitance and mutual-capacitance electrodes simultaneously, with noise immunity from the integrated adjacent key suppression. Designers combine the MCU with a TFT or OLED display controller over SPI or parallel 8080 interface using the SERCOM modules. The 256 KB Flash is sufficient for full GUI frameworks, and the 32 KB SRAM buffers partial-frame updates without external memory.
Recommended
Industrial Metering and Data Acquisition
In industrial metering, the ATSAMD20J18A-CU's 12-bit ADC with up to 20 channels captures analog signals from voltage, current, and temperature sensors with simultaneous sampling supported by the Event System. The 256 KB Flash stores calibration tables, metering algorithms, and communication protocol stacks (Modbus RTU, DLMS/COSEM, IEC 62056), while the 32 KB SRAM buffers instantaneous measurement windows for energy calculations. RTC with calendar mode enables accurate time-stamping of consumption records. The wide 1.62 V to 3.63 V supply range and -40C to +85C industrial temperature grade suit outdoor meter enclosures.
Recommended
Portable Consumer Wearable Device
Wearable fitness trackers and smart watches benefit from the ATSAMD20J18A-CU's ultra-low deep-sleep current under 1 uA with RTC retention, extending coin-cell life across multi-month deployments. The Cortex-M0+ at 48 MHz provides responsive UI rendering and sensor-fusion processing, while the 256 KB Flash stores Bluetooth Low Energy profiles, heart-rate algorithms, and step-count models. The 12-bit ADC digitizes pulse oximeter, heart-rate, and motion sensor outputs, and the six SERCOM modules connect to BLE SoCs, accelerometers, and PMOLED displays simultaneously. Compact 64-ball UFBGA 5x5 mm package fits wrist-worn form factors.
Recommended
Battery-Powered IoT Edge Node
The ATSAMD20J18A-CU serves as the central processor in battery-powered IoT edge nodes that aggregate data from multiple sensors before forwarding to a gateway. Its Cortex-M0+ core achieves 2.46 CoreMark/MHz while consuming only 70 uA/MHz, and six 16-bit Timer/Counters handle sensor sampling, watchdog, and time-slot scheduling without CPU wakeup overhead. The SERCOM peripherals connect to environmental sensors via I2C, to accelerometers via SPI, and to a wireless module via UART, all while maintaining sub-1 uA standby between measurement cycles. The 1.62 V to 3.63 V supply range matches lithium primary cells directly, eliminating boost converters and improving system efficiency.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD20J18A-CU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD20J17A-CNT | ATSAMD20J16A-CNT | ATSAMD20J15A-CU | ATSAMD21J18A-CU | STM32F072CBU6 |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | STMicroelectronics |
| Package | 64-ball UFBGA 5x5 mm | 64-ball UFBGA 5x5 mm (same) | 64-ball UFBGA 5x5 mm (same) | 64-ball UFBGA 5x5 mm (same) | 64-ball UFBGA 5x5 mm (same) | 48-pin QFN (different) |
| Core | ARM Cortex-M0+ 48 MHz | ARM Cortex-M0+ 48 MHz | ARM Cortex-M0+ 48 MHz | ARM Cortex-M0+ 48 MHz | ARM Cortex-M0+ 48 MHz (D21) | ARM Cortex-M0 48 MHz |
| Flash | 256 KB | 128 KB (-50%) | 64 KB (-75%) | 32 KB (-87%) | 256 KB (same) | 128 KB (-50%) |
| SRAM | 32 KB | 16 KB | 8 KB | 4 KB | 32 KB (same) | 16 KB |
| USB | FS USB 2.0 Device | FS USB 2.0 Device | FS USB 2.0 Device | FS USB 2.0 Device | FS USB 2.0 Host+Device | FS USB 2.0 Device |
| Touch (PTC) | 256 channels | 256 channels | 256 channels | 256 channels | 256 channels | TSC 24 channels (different) |
| Operating Voltage | 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 | 2.0 V to 3.6 V |
Key Differentiators
- Industry-leading 256-channel Peripheral Touch Controller (PTC) (vs STM32F072CBU6)
- Hex-compatible firmware migration across the SAM D20 family (vs ATSAMD20J17A-CNT)
- Seamless upgrade path to SAM D21 with USB host and I2S (vs ATSAMD21J18A-CU)
Design Notes
Place one 100 nF decoupling capacitor as close as physically possible to each VDDIO and VDDANA pin pair, with a 4.7 uF bulk capacitor on the same supply rail. Per Microchip SAM D20 hardware design guidelines, this decoupling scheme prevents logic-noise coupling into the analog domain and keeps the 12-bit ADC SNR within datasheet limits. For battery applications, add a 10 uF reservoir capacitor near the MCU to handle radio-transmit current spikes without VDDIO droop.
Estimated: at 48 MHz CPU clock and 1.8 V supply, the ATSAMD20J18A-CU active power is approximately 3.4 mW (70 uA/MHz * 48 MHz * 1.8 V); at 3.3 V supply, it rises to about 11 mW. The 64-ball UFBGA 5x5 mm package has an estimated theta_JA of 40 C/W on a standard 4-layer JEDEC test board, so active power dissipation of 11 mW produces only 0.4 C junction temperature rise. No external heatsink is required, but continuous active operation at 85 C ambient is well within thermal limits.
Do not assume the SERCOM peripheral pads are interchangeable across ATSAMD20 family members without consulting the device-specific pinout map, because the SERCOM instance number (0-5) is mapped to fixed pad locations on each package. According to Microchip SAM D20 migration documentation, firmware written for ATSAMD20J18 must be re-mapped (not recompiled without changes) when migrating to smaller Flash variants in the same package. Always regenerate the Atmel START or MPLAB Harmony pinout table when changing parts.
For USB applications, route DP and DM as a 90 ohm differential pair with reference to a continuous unbroken ground plane on layer 2, using microstrip topology on the top layer. Place the 1.0 uF USB transceiver bypass capacitor (USB_VBUS pin) within 2 mm of the package, and add a 48 MHz crystal with two 20 pF load capacitors within 3 mm of the XIN/XOUT pins. Microchip SAM D20 hardware checklist recommends these stack-up rules to pass USB-IF compliance testing on first prototypes.
Compliance Information
RoHS and REACH compliance per Microchip product page and SAM D20 datasheet environmental section. Industrial temperature grade (-40C to +85C) standard; AEC-Q100 automotive grade not available for this part number.
