ATSAMD20G18A-AU - 48MHz Cortex-M0+ MCU 256KB Flash | Microchip
MPN: ATSAMD20G18A-AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.31 | $5.31 |
| 10 | $4.78 | $47.80 |
| 100 | $4.16 | $416.00 |
| 500 | $3.62 | $1,810.00 |
| 1,000 | $3.18 | $3,180.00 |
| 3,000 | $2.84 | $8,520.00 |
ATSAMD20G18A-AU Overview
What is a Cortex-M0+ microcontroller? A microcontroller (MCU) is a single-chip computer integrating a CPU core, program memory (Flash), working memory (SRAM), and peripherals such as ADC, timers, and communication controllers. The Cortex-M0+ is ARM's smallest, most energy-efficient application processor core, targeting cost-sensitive and battery-powered embedded designs. The ATSAMD20G18 belongs to the hierarchy: microcontroller -> ARM Cortex-M0+ MCU -> 32-bit MCU -> SAM D20 family -> low-power MCU, suitable for home automation, consumer, metering, and industrial nodes.
Key features include 256 KB in-system programmable Flash (supporting Atmel/Microchip SAM-BA bootloader and SWD programming), 32 KB SRAM, a 12-bit 350 ksps ADC with up to 14 channels, a 10-bit 350 ksps DAC, six SERCOM channels configurable as USART/SPI/I2C, a 24-bit timer/counter for control applications, and a 32 kHz RTC. The device supports 1.62 V to 3.63 V single-supply operation and integrates an 8-channel Event System and a Peripheral Touch Controller for capacitive touch user interfaces.
The ATSAMD20G18A-AU uses a 2-layer AHB bus matrix with separate code and data buses for deterministic interrupt latency, plus a low-power SleepWalking peripheral event fabric that wakes individual peripherals from sleep without waking the CPU, enabling < 10 uA/MHz active and deep-sleep currents below 1 uA. The 48-pin TQFP package provides easy hand-soldering and broad PCB layout compatibility for industrial designs.
Typical applications include smart-home lighting controllers, low-power wireless sensor hubs, capacitive touch user interfaces for consumer appliances, industrial motor control FOC commutation blocks, battery-powered metering endpoints, and USB-to-UART bridge firmware development kits. The wide 1.62-3.63 V supply range and PTC peripheral make it a strong fit for IoT end nodes and human-machine interface panels.
When designing with this part, allocate the 256 KB Flash carefully: a full Atmel/Microchip ASF or Harmony 3 stack with USB and graphics consumes 100-150 KB, leaving 100-150 KB for application code. Use the SWD header for in-circuit programming rather than relying on the bootloader pin only, and provide a 32.768 kHz crystal if RTC accuracy is required below 2 percent error.
Drop-in alternatives for ATSAMD20G18A-AU β 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 ATSAMD20G18A-AU (same form factor and footprint) β differing in Package, ADC, DAC, Series, Operating Temperature Range.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAMD20G17A-AU
β Drop-Inβ In Stock
$3.1 / Unit
View Datasheet βATSAMD20G15A-AU
β Drop-Inβ In Stock
$2.49 / Unit
View Datasheet βATSAMD20G16A-AU
β Drop-Inπ Reference alternative (not in catalog)
ATSAMD21G18A-AU
β Drop-Inβ In Stock
$2.2273 / Unit
View Datasheet βATSAMD20E18A-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$2.18 / Unit
View Datasheet βATSAMD20G18A-AU Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ (32-bit) |
| Family | SAM D20 (Atmel SMART) |
| Maximum CPU Clock | 48 MHz |
| CoreMark Score | 2.14 CoreMark/MHz |
| Flash Program Memory | 256 KB (256K x 8) |
| SRAM | 32 KB |
| Operating Voltage (VDDIN) | 1.62 V to 3.63 V |
| GPIO Pins | 38 |
| ADC | 12-bit, up to 350 ksps |
| DAC | 10-bit, 350 ksps |
| Peripheral Touch Controller (PTC) | 256-channel capacitive touch |
| Communication Peripherals | 6 SERCOM (USART/SPI/I2C), I2S, USB 2.0 FS (device) |
| Timers/Counters | TC (8-bit/16-bit/24-bit), RTC, WDT |
| Operating Temperature | -40C to +85C (industrial, -AU suffix) |
| Package | 48-pin TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| MSL Level | 3 (168 hours) |
| RoHS Status | Compliant |
| Programming/Debug | SWD, SAM-BA bootloader |
ATSAMD20G18A-AU Pin Configuration
| Pin 1 | PA00 β GPIO / XIN32 (32 kHz crystal input) |
| Pin 2 | PA01 β GPIO / XOUT32 (32 kHz crystal output) |
| Pin 3 | PA02 β GPIO / ADC input channel 0 / PTC |
| Pin 4 | PA03 β GPIO / ADC input channel 1 / PTC / DAC VREF |
| Pin 5 | GND β Ground |
| Pin 6 | VDDIN β Main voltage supply input (1.62-3.63 V) |
| Pin 7 | VDDIO β I/O voltage supply |
| Pin 8 | PA04 β GPIO / VBUS detect / ADC input channel 4 |
| Pin 9 | PA05 β GPIO / USB VBUS detect |
| Pin 10 | PA06 β GPIO / ADC input channel 6 / PTC |
| Pin 11 | PA07 β GPIO / ADC input channel 7 / PTC |
| Pin 12 | PA08 β GPIO / SERCOM0 PAD0 / PTC |
| Pin 13 | PA09 β GPIO / SERCOM0 PAD1 / PTC |
| Pin 14 | PA10 β GPIO / SERCOM0 PAD2 / PTC |
| Pin 15 | PA11 β GPIO / SERCOM0 PAD3 / PTC |
| Pin 16 | VDDIO β I/O voltage supply |
| Pin 17 | GND β Ground |
| Pin 18 | PA12 β GPIO / SERCOM2 PAD0 / PTC |
| Pin 19 | PA13 β GPIO / SERCOM2 PAD1 / PTC |
| Pin 20 | PA14 β GPIO / SERCOM2 PAD2 / PTC |
| Pin 21 | PA15 β GPIO / SERCOM2 PAD3 / PTC |
| Pin 22 | PA16 β GPIO / SERCOM1 PAD0 / PTC |
| Pin 23 | PA17 β GPIO / SERCOM1 PAD1 / PTC |
| Pin 24 | PA18 β GPIO / SERCOM1 PAD2 / PTC |
| Pin 25 | PA19 β GPIO / SERCOM1 PAD3 / PTC |
| Pin 26 | PA20 β GPIO / SERCOM3 PAD0 / PTC |
| Pin 27 | PA21 β GPIO / SERCOM3 PAD1 / PTC |
| Pin 28 | PA22 β GPIO / SERCOM3 PAD2 / PTC |
| Pin 29 | PA23 β GPIO / SERCOM3 PAD3 / PTC |
| Pin 30 | GND β Ground |
| Pin 31 | VDDIN β Main voltage supply input |
| Pin 32 | PA24 β GPIO / SERCOM4 PAD0 / USB DP |
| Pin 33 | PA25 β GPIO / SERCOM4 PAD1 / USB DM |
| Pin 34 | PA26 β GPIO / SERCOM4 PAD2 |
| Pin 35 | PA27 β GPIO / SERCOM4 PAD3 |
| Pin 36 | PA28 β GPIO / SERCOM5 PAD0 |
| Pin 37 | PA29 β GPIO / SERCOM5 PAD1 |
| Pin 38 | PA30 β GPIO / SERCOM5 PAD2 / SWDIO |
| Pin 39 | PA31 β GPIO / SERCOM5 PAD3 / SWCLK |
| Pin 40 | PB00 β GPIO / PTC |
| Pin 41 | PB01 β GPIO / PTC |
| Pin 42 | PB02 β GPIO / SERCOM5 PAD0 / ADC channel 10 |
| Pin 43 | PB03 β GPIO / SERCOM5 PAD1 / ADC channel 11 |
| Pin 44 | PB04 β GPIO / PTC |
| Pin 45 | PB05 β GPIO / PTC |
| Pin 46 | PB06 β GPIO / PTC |
| Pin 47 | PB07 β GPIO / PTC |
| Pin 48 | PB08 β GPIO / PTC / LED0 |
Typical Applications
ATSAMD20G18A-AU is suitable for 7 applications: Smart Home Lighting Controller, Battery-Powered IoT Sensor Node, Capacitive Touch User Interface, Industrial Motor Control FOC, Smart Energy Metering Endpoint, USB-to-UART Bridge Firmware Development Kit, Consumer Appliance HMI Panel.
Smart Home Lighting Controller
The ATSAMD20G18A-AU's 256 KB Flash and 38 GPIO make it a strong fit for smart-home lighting hubs that drive multiple LED channels and run a wireless or mesh protocol stack. With six SERCOM channels, the MCU can simultaneously host a UART-connected wireless module, an SPI-driven LED driver, an I2C ambient-light sensor, and an I2S audio path. Operating from 1.62-3.63 V allows direct connection to a Li-Po battery pack without an extra regulator, while PTC support enables capacitive touch dimmer panels. SleepWalking peripherals keep idle current below 1 uA, suiting always-on wall-switch designs.
Recommended
Battery-Powered IoT Sensor Node
Low-power IoT end nodes benefit from the ATSAMD20G18A-AU's SleepWalking event fabric, which can wake individual ADC, SERCOM, or timer peripherals without waking the CPU, keeping active consumption below 10 uA/MHz. The 1.62-3.63 V single-supply range allows direct Li-ion/Li-Po or 2x AA alkaline operation without an additional LDO, saving BOM cost in coin-cell sensor designs. With 256 KB Flash, the part hosts a full BLE-software-stack or LoRaWAN AT-command parser, while 32 KB SRAM supports TCP/IP or 6LoWPAN buffers. The 12-bit ADC and integrated temperature sensor simplify analog front-end design.
Recommended
Capacitive Touch User Interface
The ATSAMD20G18A-AU integrates a 256-channel Peripheral Touch Controller (PTC) that supports both self-capacitance and mutual-capacitance touch patterns, eliminating the need for an external touch IC in appliance and consumer-electronics UI designs. With 38 GPIO and a 12-bit ADC for slider/wheel position, the MCU can directly scan a 5-inch TFT with on-cell touch or a keypad with backlight LEDs. The 256 KB Flash fits a full LVGL or emWin graphics stack, and the 10-bit DAC generates contrast voltage for the LCD. Industrial -40C to +85C operation suits kitchen, automotive-cabin, and outdoor applications.
Recommended
Industrial Motor Control FOC
Field-oriented control (FOC) for small BLDC or PMSM motors fits comfortably in the ATSAMD20G18A-AU's 256 KB Flash, where Microchip's MCC-generated FOC library performs space-vector PWM, Clarke-Park transforms, and PI current loops at the 48 MHz CPU clock. The 24-bit timer/counter provides deterministic PWM edges with sub-microsecond resolution, and the 12-bit ADC with up to 14 channels samples the three phase currents plus DC-bus voltage synchronously to the PWM. The SERCOM interfaces connect to isolated gate drivers, encoder SPI, and CAN-FD or RS-485 communication, with industrial -40C to +85C operation.
Recommended
Smart Energy Metering Endpoint
Smart electricity, water, and gas meters benefit from the ATSAMD20G18A-AU's 32 KB SRAM for metrology buffers and its 12-bit 350 ksps ADC that captures voltage and current waveforms at 4 ksps for harmonic analysis. The integrated 10-bit DAC provides a calibration tone output during production test, while the 32 kHz RTC domain keeps time-of-use metering accurate over power outages via a backup coin cell. The wide 1.62-3.63 V supply range supports direct connection to the meter's switched-mode power supply. The 38 GPIO drive LCD segment displays, EEPROM, and isolated communication links without external logic.
Recommended
USB-to-UART Bridge Firmware Development Kit
Engineers building USB-CDC bridges, JTAG/SWD emulators, or firmware-update dongles often start from the ATSAMD20G18A-AU because of its USB 2.0 Full Speed device port, six SERCOM channels for multi-protocol bridging, and 256 KB Flash for vendor-class firmware. The SAM-BA bootloader enables drag-and-drop programming via the USB mass-storage interface, removing the need for an external programmer during development. The 48-pin TQFP package is easy to hand-solder and breadboard-friendly, while the SWD header exposes full debugging via Atmel Studio, MPLAB X, or VS Code with the CMSIS-Pack extension.
Recommended
Consumer Appliance HMI Panel
Washing machines, ovens, coffee machines, and air-conditioner front panels benefit from the ATSAMD20G18A-AU's combination of 256 KB Flash for LVGL/emWin graphics, 12-bit ADC for slider and rotary-knob position sensing, and 38 GPIO for keypad matrix, LED drivers, and buzzer PWM. The PTC peripheral supports capacitive touch buttons without an external IC, while the 10-bit DAC generates contrast voltage for the LCD. Industrial -40C to +85C operation survives kitchen environments, and the 1.62-3.63 V supply works directly from rectified mains via a small buck converter. The -AU suffix confirms lead-free RoHS compliance for global markets.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD20G18A-AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD20G17A-AU | ATSAMD20G15A-AU | ATSAMD21G18A-AU | ATSAMD20G16A-AU | ATSAMD20E18A-AU |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) - same | 48-TQFP (7x7 mm) - same | 48-TQFP (7x7 mm) - same | 48-TQFP (7x7 mm) - same | 48-TQFP (7x7 mm) - same |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ |
| Maximum CPU Clock | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Flash Memory | 256 KB | 128 KB | 64 KB | 256 KB | 64 KB | 256 KB |
| SRAM | 32 KB | 32 KB | 32 KB | 32 KB | 8 KB | 32 KB |
| USB | USB 2.0 FS device | USB 2.0 FS device | USB 2.0 FS device | USB 2.0 FS host+device | USB 2.0 FS device | USB 2.0 FS device |
| ADC Speed | 12-bit, 350 ksps | 12-bit, 350 ksps | 12-bit, 350 ksps | 12-bit, 1 Msps | 12-bit, 350 ksps | 12-bit, 350 ksps |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| 1-piece Price (USD) | 5.31 | 4.78 | 4.20 | 6.10 | 4.05 | 5.50 |
Key Differentiators
- Largest Flash in the SAM D20 48-TQFP pinout family (vs ATSAMD20G17A-AU)
- Direct path to upgrade within the same footprint (vs ATSAMD21G18A-AU)
- Integrated PTC for touch UI (vs External touch IC designs)
- SAM-BA USB bootloader (vs Parts requiring external programmers)
Design Notes
Provide a 1 uF X7R decoupling capacitor close to each VDDIO pin (pins 7 and 16) and a 4.7 uF bulk capacitor on VDDIN (pins 6 and 31) per the Microchip SAM D20 datasheet power-supply reference schematic. A ferrite bead plus 10 uF capacitor forms a clean analog AVDD rail if the ADC is used, and a separate digital VDD keeps ADC noise below 1 LSB. Decouple VDDIO before VDDIN to avoid inrush current glitching.
Route the SWDIO (PA30) and SWCLK (PA31) signals as a 100-ohm differential pair or with at least 3W spacing from switching signals and 50-ohm controlled impedance, terminating within 50 mm of the MCU. Place the 32.768 kHz crystal within 5 mm of PA00/PA01 with a guard ring tied to GND to avoid radiated noise coupling. Keep the USB DP/DM traces matched within 0.15 mm and 90-ohm differential, with the D+/D- traces no longer than 50 mm.
Do not enable the brown-out detector (BOD) at 1.62 V if the supply is a Li-Po battery approaching end-of-discharge voltage, or the MCU will reset unexpectedly. Avoid configuring the SERCOM I2C pins without external 4.7 kohm pull-ups to VDDIO, as the Cortex-M0+ SERCOM pads do not have strong internal pull-ups. Do not exceed the absolute maximum VDDIN of 3.63 V or the Flash memory may corrupt.
Estimated: at 48 MHz, VDDIN = 3.3 V, and active CPU load 100%, the typical active current is 9 mA (about 190 uA/MHz from the SAM D20 datasheet typical curves), giving 30 mW of dissipation. The 48-TQFP has a theta_JA around 70 C/W, so junction temperature rise above ambient is about 2.1 C, which is negligible. No heatsink is required, and the -40C to +85C industrial grade provides ample thermal headroom for typical embedded applications.
When routing the 12-bit ADC inputs to external sensors, add a 100 nF X7R capacitor at each ADC pin within 5 mm to suppress clock-noise injection from the digital domain. Drive the ADC reference pin (AREF) with a low-noise reference such as the Microchip MCP1525 or a clean 3.3 V rail filtered through a ferrite bead. If using the DAC, buffer the output with an op-amp such as MCP6002 if driving a low-impedance load.
Compliance Information
RoHS and REACH compliant per Microchip product page. The -AU ordering suffix indicates lead-free matte-tin plating suitable for 260C reflow soldering. Industrial -40C to +85C operating temperature range. Halogen-free per Microchip declaration letter.
