ATSAMD20G18A-MU - ARM Cortex-M0+ 48MHz 256KB MCU | Microchip
MPN: ATSAMD20G18A-MU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.42 | $5.42 |
| 10 | $4.92 | $49.20 |
| 100 | $4.41 | $441.00 |
| 500 | $3.95 | $1,975.00 |
| 1,000 | $3.51 | $3,510.00 |
ATSAMD20G18A-MU Overview
An ARM Cortex-M0+ microcontroller (MCU) is a low-power, energy-efficient 32-bit processor core designed by ARM Holdings, commonly used in embedded systems that require deterministic real-time performance at low cost. The Cortex-M0+ sits in the hierarchy microcontroller -> embedded processor -> SoC -> semiconductor IC, and the SAM D20 series extends it with Microchip's peripheral mix and event system for low-power IoT and industrial designs.
Key features of the ATSAMD20G18A-MU include six SERCOM interfaces configurable as USART, I2C, or SPI; a 12-bit 350 ksps ADC with up to 14 channels; a 10-bit 350 ksps DAC; a 16-bit timer/counter; an RTC with calendar mode; and a full-speed USB 2.0 device interface. The device operates from 1.62V to 3.63V and supports Sleep, Idle, Standby, and Backup low-power modes with typical active current under 3 mA at 48 MHz.
The ATSAMD20G18A-MU uses a Harvard-bus architecture with single-cycle I/O access and an integrated Peripheral Event System that allows peripherals to communicate without CPU intervention, reducing latency and power. The 256 KB Flash is organized in two banks for in-application programming, supporting live firmware updates. The SAM D20 family is code-compatible with SAM D10 and SAM D21, easing migration.
Typical applications include IoT sensor nodes, smart home automation, industrial metering and HMI, consumer electronics, BLE beacons (paired with external transceivers), and low-power motor control. The combination of Cortex-M0+ efficiency, generous memory, and flexible SERCOM peripherals addresses cost-sensitive yet feature-rich designs.
Designers should pay attention to the 1.62V minimum supply for full-speed USB operation, the need for proper decoupling on each VDD pin, and the use of Microchip's Atmel Studio / MPLAB X IDE with the ASF or Harmony 3 frameworks. Programming is supported via SWD using tools such as Atmel-ICE or MPLAB PICkit 4.
This page consolidates distributor pricing, verified drop-in SAM D20 alternatives, and practical design notes for the ATSAMD20G18A-MU that are not directly listed in the manufacturer datasheet, helping engineers select and source the part efficiently.
Drop-in alternatives for ATSAMD20G18A-MU 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-MU (same form factor and footprint) β differing in Package, ADC, Operating Temperature, DAC, SRAM.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAMD20G18A-MUT
β Drop-Inπ Reference alternative (not in catalog)
ATSAMD20G17A-MU
β Drop-Inβ In Stock
$1.93 / Unit
View Datasheet βATSAMD20G18A-AU
β Drop-Inβ In Stock
$2.84 / Unit
View Datasheet βATSAMD20G18A-MU Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Series | SAM D20 |
| Core | ARM Cortex-M0+ |
| Data Bus Width | 32 bit |
| Maximum Clock Frequency | 48 MHz |
| Program Memory Size (Flash) | 256 KB (256K x 8) |
| RAM Size | 32 KB |
| Operating Supply Voltage | 1.62 V to 3.63 V |
| Package | 48-QFN (7x7 mm) |
| Mounting Type | Surface Mount |
| Number of I/O Pins | 38 |
| ADC | 12-bit, up to 14 channels, 350 ksps |
| DAC | 10-bit, 350 ksps |
| Communication Interfaces | 6x SERCOM (USART/I2C/SPI), USB 2.0 FS |
| Timers | 16-bit TC, 32-bit TC, RTC |
| CoreMark/MHz | 2.14 |
| Operating Temperature Range | -40C to +85C (industrial) |
| RoHS Status | Compliant |
ATSAMD20G18A-MU Pin Configuration
| Pin 1 | PA00 β GPIO / XIN |
| Pin 2 | PA01 β GPIO / XOUT |
| Pin 3 | PA02 β GPIO / ADC[0] |
| Pin 4 | PA03 β GPIO / ADC[1] |
| Pin 5 | GND β Ground |
| Pin 6 | VDD β Digital supply voltage |
| Pin 7 | PA04 β GPIO / ADC[2] |
| Pin 8 | PA05 β GPIO / ADC[3] |
| Pin 9 | PA06 β GPIO / ADC[4] |
| Pin 10 | PA07 β GPIO / ADC[5] |
| Pin 11 | PA08 β GPIO / ADC[6] |
| Pin 12 | PA09 β GPIO / ADC[7] |
| Pin 13 | PA10 β GPIO / ADC[8] |
| Pin 14 | PA11 β GPIO / ADC[9] |
| Pin 15 | PA12 β GPIO |
| Pin 16 | PA13 β GPIO |
| Pin 17 | PA14 β GPIO / XIN32 |
| Pin 18 | PA15 β GPIO / XOUT32 |
| Pin 19 | PA16 β GPIO / I2S SCK |
| Pin 20 | PA17 β GPIO / I2S FS |
| Pin 21 | PA18 β GPIO / I2S MCK |
| Pin 22 | PA19 β GPIO / I2S SDO |
| Pin 23 | PA20 β GPIO / I2S SDI |
| Pin 24 | PA21 β GPIO / USB_DP |
| Pin 25 | PA22 β GPIO / USB_DM |
| Pin 26 | PA23 β GPIO |
| Pin 27 | PA24 β GPIO / USB_SOF |
| Pin 28 | PA25 β GPIO |
| Pin 29 | GND β Ground |
| Pin 30 | VDD β Digital supply voltage |
| Pin 31 | PB00 β GPIO |
| Pin 32 | PB01 β GPIO |
| Pin 33 | PB02 β GPIO / ADC[10] |
| Pin 34 | PB03 β GPIO / ADC[11] |
| Pin 35 | PB04 β GPIO / ADC[12] |
| Pin 36 | PB05 β GPIO / ADC[13] |
| Pin 37 | PB06 β GPIO |
| Pin 38 | PB07 β GPIO |
| Pin 39 | PB08 β GPIO |
| Pin 40 | PB09 β GPIO |
| Pin 41 | PB10 β GPIO |
| Pin 42 | PB11 β GPIO |
| Pin 43 | PB12 β GPIO |
| Pin 44 | PB13 β GPIO |
| Pin 45 | PB14 β GPIO |
| Pin 46 | PB15 β GPIO |
| Pin 47 | RESETN β Reset input (active low) |
| Pin 48 | GND β Exposed pad / thermal pad ground |
Typical Applications
ATSAMD20G18A-MU is suitable for 6 applications: IoT Sensor Nodes, Smart Home Automation, Industrial Metering and HMI, Consumer Electronics, Low-Power Motor Control, USB HID Devices.
IoT Sensor Nodes
The ATSAMD20G18A-MU fits IoT sensor node designs because its ARM Cortex-M0+ core draws low active current while running at 48 MHz, and its Sleep and Standby modes with RTC wake-up enable multi-year coin-cell life. With 256 KB Flash, designers can host LoRaWAN or BLE stack libraries alongside application logic, while the 32 KB SRAM supports sensor buffering. Six configurable SERCOM interfaces (USART/SPI/I2C) connect to common sensors such as temperature, humidity, and accelerometers.
Recommended
Smart Home Automation
The ATSAMD20G18A-MU powers smart-home hubs, thermostats, and lighting controllers thanks to its Cortex-M0+ efficiency and generous peripheral mix. The six SERCOM ports handle Wi-Fi or BLE module SPI/UART links, the 12-bit ADC reads analog sensors like NTC thermistors, and the 10-bit DAC drives LED dimming outputs. Low-power Standby with RTC wake-up ensures battery-powered door and window sensors can run for years.
Recommended
Industrial Metering and HMI
The ATSAMD20G18A-MU suits industrial metering and HMI panels because its 256 KB Flash stores complex UI and calibration routines, while the 12-bit ADC measures analog sensors at up to 350 ksps. The Peripheral Event System allows timer-driven ADC sampling without CPU intervention, freeing Cortex-M0+ cycles for HMI rendering on SPI-connected LCDs. Industrial -40C to +85C temperature range covers factory environments.
Recommended
Consumer Electronics
The ATSAMD20G18A-MU drives consumer electronics such as wearables, toys, and remote controls due to its Cortex-M0+ cost-effectiveness and Microchip's mature peripheral ecosystem. USB 2.0 full-speed device support enables HID-class peripherals without an external bridge chip, and 38 GPIO accommodate key matrices and LED arrays. The Harmony 3 software framework shortens development of BLE-enabled consumer products.
Recommended
Low-Power Motor Control
The ATSAMD20G18A-MU handles low-power motor control loops in BLDC drivers, fans, and small pumps. Its 16-bit and 32-bit timer/counters provide PWM generation at frequencies suitable for sensorless trapezoidal commutation, while the 12-bit ADC samples back-EMF or current sense. Cortex-M0+ efficiency and fast interrupt response keep torque ripple low. The 256 KB Flash holds state-machine control algorithms.
Recommended
USB HID Devices
The ATSAMD20G18A-MU is ideal for USB HID-class devices such as keyboards, mice, custom input controllers, and HID-mouse dongles. The integrated USB 2.0 full-speed device port eliminates external bridge ICs and supports both Bus-powered and Self-powered designs. The 256 KB Flash hosts HID descriptors, macro logic, and BLE-coexistence code. The QFN-48 package and small BOM suit compact peripherals.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD20G18A-MU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD20G18A-MUT | ATSAMD20G17A-MU | ATSAMD20G18A-AU |
|---|---|---|---|---|
| Package | 48-QFN (7x7) | 48-QFN (7x7) - same | 48-QFN (7x7) - same | 48-TQFP - different land pattern |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ |
| Max Clock Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Flash Size | 256 KB | 256 KB | 128 KB (-50%) | 256 KB |
| SRAM Size | 32 KB | 32 KB | 32 KB | 32 KB |
| Number of I/O | 38 | 38 | 38 | 38 |
| USB Interface | USB 2.0 FS | USB 2.0 FS | USB 2.0 FS | USB 2.0 FS |
Key Differentiators
- Higher Flash density in same QFN footprint (vs ATSAMD20G17A-MU)
- Drop-in silicon compatibility for high-volume production (vs ATSAMD20G18A-MUT)
- TQFP option for hand-rework friendly assembly (vs ATSAMD20G18A-AU)
Design Notes
Place a 100 nF decoupling capacitor on each VDD pin as close to the IC as possible, with an additional bulk 4.7 uF or 10 uF capacitor near the package. For USB operation, ensure VDD is at least 3.0 V; for full 48 MHz operation use at least 2.7 V. Below 2.7 V, the maximum clock must be limited to 24 MHz or lower. Route analog and digital supplies separately when using the ADC for precision measurements.
The QFN-48 package exposes a thermal pad (EP) on the underside which must be soldered to a ground plane with thermal vias for heat dissipation. At 48 MHz active mode the device typically draws under 3 mA, so thermal management is rarely a constraint for normal operation. In Standby with RTC running, current drops to a few microamps; designers should confirm thermal performance in enclosed housings.
Route the SWD signals (SWDIO, SWCLK) directly to a 10-pin Cortex Debug connector with a 4.7 kOhm pull-up on SWDIO. Keep the SWD traces under 100 mm and isolated from analog signals. Place the 32.768 kHz crystal close to XIN32/XOUT32 (pins 17-18) with grounded guard traces. Use impedance-controlled routing for USB DP/DM (90 ohm differential).
Do not exceed 3.63 V on any VDD pin. The NRST line is active-low and must be pulled high for normal operation; floating reset can cause boot loops. SERCOM pin mapping is flexible but I2C lines need external pull-ups. For bootloader updates, ensure BOOTPROT is configured correctly or the device may brick after firmware updates.
Compliance Information
RoHS compliant per Microchip product page and jrhelectronics listing. Industrial temperature grade -40C to +85C. AEC-Q100 not applicable for non-automotive part number.
