ATSAMD20E18A-MNT - 256KB Flash ARM Cortex-M0+ MCU | Microchip
MPN: ATSAMD20E18A-MNT β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.85 | $3.85 |
| 10 | $3.47 | $34.70 |
| 100 | $3.1 | $310.00 |
| 500 | $2.79 | $1,395.00 |
| 1,000 | $2.48 | $2,480.00 |
ATSAMD20E18A-MNT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program and data memory, and a rich set of peripherals. The ARM Cortex-M0+ is the smallest and most energy-efficient ARM core, optimized for low-power deterministic interrupt response, while the SAM D20E series adds Microchip-specific peripherals, power management, and an event system. Within the broader taxonomy, the ATSAMD20 sits between 8-bit AVR/PIC MCUs and higher-performance Cortex-M3/M4 parts, making it the canonical choice for cost-sensitive, battery-powered, sensor-centric products.
Key features of the ATSAMD20E18A-MNT include 6 SERCOM (serial communication) interfaces configurable as I2C/SPI/UART, a 12-bit 350 ksps ADC with up to 20 channels, a 10-bit DAC, a 256-channel Peripheral Touch Controller (PTC) for capacitive buttons and sliders, and a full-speed USB 2.0 device port. The integrated event system allows peripherals to trigger one another without CPU intervention, freeing the Cortex-M0+ core for application logic and reducing active current.
Technically, the device operates from 1.62 V to 3.63 V, supports Sleep, Idle, Standby, and Backup sleep modes with sub-microamp standby current, and includes a 32.768 kHz RTC with calendar. The Cortex-M0+ core reaches 2.14 CoreMark/MHz, and the Memory Protection Unit (MPU) helps harden RTOS-based firmware against runaway pointers. Programming is via the integrated Serial Wire Debug (SWD) interface and the Microchip Atmel Studio / MPLAB X toolchain.
Typical applications include home automation nodes (HVAC, lighting, smart plugs), industrial sensor transmitters, consumer wearables and fitness bands, low-power wireless sensor nodes (when paired with an AT86RF233 or similar 2.4 GHz radio), capacitive-touch user interfaces, and USB peripherals such as HID controllers. The wide operating voltage and rich analog peripherals make it ideal for battery-powered measurement products.
When designing with this part, choose decoupling capacitors per the datasheet (typically one 100 nF per VDD pin) and route SWD signals on inner layers with a ground return path. For best EMC performance, the exposed pad must be soldered to a contiguous ground plane, and unused I/O pins should be configured as outputs low rather than left floating.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, and design notes not found on the manufacturer datasheet alone, helping engineers shorten the BOM-evaluation cycle for ATSAMD20-based designs.
Drop-in alternatives for ATSAMD20E18A-MNT 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 ATSAMD20E18A-MNT (same form factor and footprint) β differing in Package, ADC, SRAM, Operating Temperature, Core Architecture.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAMD20E17A-MNT
β Drop-Inπ Reference alternative (not in catalog)
ATSAMC20E18A-MUT
β Drop-Inβ In Stock
$1.92 / Unit
View Datasheet βATSAMD20E16B-MN
β Drop-Inβ In Stock
$1.62 / Unit
View Datasheet βATSAMD20E18A-MNT Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ (32-bit) |
| Maximum CPU Frequency | 48 MHz |
| CoreMark/MHz | 2.14 |
| Program Flash Memory | 256 KB |
| SRAM | 32 KB |
| Package | 32-pin VQFN (5x5 mm) with exposed pad |
| Operating Voltage Range | 1.62 V to 3.63 V |
| GPIO Count | 26 (varies by package) |
| ADC | 12-bit, up to 20 channels, 350 ksps |
| DAC | 10-bit, 1 channel |
| Communication Interfaces | 6x SERCOM (configurable I2C/SPI/UART), I2S |
| USB | USB 2.0 Full-Speed Device |
| Touch Controller | 256-channel Peripheral Touch Controller (PTC) |
| Timers | 16-bit TC x3, 32-bit TCC x2, RTC |
| Operating Temperature | -40C to +105C |
| Debug Interface | Serial Wire Debug (SWD) |
| Memory Protection Unit | Yes (8 regions) |
| RoHS Status | Compliant |
ATSAMD20E18A-MNT Pin Configuration
| Pin 1 | PA00 β GPIO / ADC input channel 0 |
| Pin 2 | PA01 β GPIO / ADC input channel 1 |
| Pin 3 | PA02 β GPIO / ADC input channel 2 / DAC output |
| Pin 4 | PA03 β GPIO / ADC input channel 3 / reference voltage |
| Pin 5 | GND β Ground |
| Pin 6 | VDD β Digital supply voltage |
| Pin 7 | VDDANA β Analog supply voltage |
| Pin 8 | PA04 β GPIO / ADC input channel 4 |
| Pin 9 | PA05 β GPIO / ADC input channel 5 |
| Pin 10 | PA06 β GPIO / ADC input channel 6 |
| Pin 11 | PA07 β GPIO / ADC input channel 7 |
| Pin 12 | PA08 β GPIO / SERCOM0 pad 0 (I2C/SPI/UART) |
| Pin 13 | PA09 β GPIO / SERCOM0 pad 1 |
| Pin 14 | PA10 β GPIO / SERCOM0 pad 2 |
| Pin 15 | PA11 β GPIO / SERCOM0 pad 3 / USB D- |
| Pin 16 | GND β Ground |
| Pin 17 | PA12 β GPIO / SERCOM1 pad 0 / USB D+ |
| Pin 18 | PA13 β GPIO / SERCOM1 pad 1 |
| Pin 19 | PA14 β GPIO / SERCOM1 pad 2 |
| Pin 20 | PA15 β GPIO / SERCOM1 pad 3 |
| Pin 21 | PA16 β GPIO / SERCOM2 pad 0 / I2S data |
| Pin 22 | PA17 β GPIO / SERCOM2 pad 1 / I2S clock |
| Pin 23 | PA18 β GPIO / SERCOM2 pad 2 |
| Pin 24 | PA19 β GPIO / SERCOM2 pad 3 |
| Pin 25 | PA20 β GPIO / SERCOM3 pad 0 |
| Pin 26 | PA21 β GPIO / SERCOM3 pad 1 |
| Pin 27 | PA22 β GPIO / SERCOM3 pad 2 |
| Pin 28 | PA23 β GPIO / SERCOM3 pad 3 |
| Pin 29 | PA24 β GPIO / SERCOM4 pad 0 |
| Pin 30 | PA25 β GPIO / SERCOM4 pad 1 |
| Pin 31 | RESET β Reset input (active low) |
| Pin 32 | SWDIO β Serial Wire Debug data |
| Pin 33 | EPAD β Exposed pad - must be soldered to ground |
Typical Applications
ATSAMD20E18A-MNT is suitable for 7 applications: Home Automation / Smart Sensor Hub, Capacitive Touch User Interface, USB HID Peripheral (Keyboard / Mouse / HID Game Controller), Industrial Sensor Transmitter (4-20 mA / Modbus), Wearable Fitness Band / Health Monitor, Smart Metering (Water / Gas / Electricity), Battery-Powered IoT Sensor Node (Sub-1 GHz / LoRa).
Home Automation / Smart Sensor Hub
The ATSAMD20E18A-MNT's 256 KB Flash, 32 KB SRAM, and Cortex-M0+ at 48 MHz make it ideal for smart home gateways that aggregate multiple wireless sensors. The 6 SERCOM ports can host SPI sensors, I2C peripherals, and a UART link to a Wi-Fi module like the ATWINC1500. The integrated 12-bit ADC handles analog thermostats and light sensors, while the USB device port enables drag-and-drop firmware updates from a PC. The 1.62 V to 3.63 V wide supply supports battery-powered thermostat or doorbell designs where 2x AA cells can run the MCU for years in standby.
Recommended
Capacitive Touch User Interface
The ATSAMD20E18A-MNT integrates a 256-channel Peripheral Touch Controller (PTC) supporting projected-capacitance touch buttons, sliders, and wheels. With 256 KB Flash, designers can host waterproof touch algorithms and gesture recognition. The 12-bit ADC supports additional proximity sensing via FPC antennas. The 1.62 V supply enables operation from 2x AA cells in remote controls. Compared to discrete PTC chips, the integrated approach saves ~$1 BOM cost and PCB area - critical for kitchen appliances and industrial control panels where button count exceeds 20.
Recommended
USB HID Peripheral (Keyboard / Mouse / HID Game Controller)
The ATSAMD20E18A-MNT's integrated USB 2.0 Full-Speed device port with internal pull-up, plus 48 MHz Cortex-M0+ for HID report encoding, makes it a drop-in solution for USB HID peripherals. The 256 KB Flash comfortably fits USB HID stacks, NKRO keyboard matrices, and consumer-grade firmware update bootloaders. The 1.62 V minimum supply supports single-cell Li-ion (3.0 to 4.2 V via internal regulator) wireless peripherals. Microchip's ASF USB stack provides HID, CDC, and vendor-class examples - designers can ship a working HID device in under a week of firmware development.
Recommended
Industrial Sensor Transmitter (4-20 mA / Modbus)
Industrial sensor transmitters demand low power, industrial temperature range (-40C to +105C - which the ATSAMD20E18A-MNT fully meets), and deterministic ADC sampling. The 12-bit 350 ksps ADC samples strain gauges, RTDs, or 4-20 mA loops with high accuracy. The 6 SERCOM ports run RS-485 Modbus RTU via a half-duplex transceiver, SPI for LCD display, and I2C for EEPROM calibration storage. The wide 1.62 V to 3.63 V supply supports loop-powered 4-20 mA designs with shunt regulation. 32 KB SRAM buffers Modbus transactions and calibration coefficients.
Recommended
Wearable Fitness Band / Health Monitor
The ATSAMD20E18A-MNT's Cortex-M0+ at 48 MHz, sub-microamp standby current, and 12-bit ADC for heart-rate optical sensors make it ideal for battery-powered fitness wearables. The 256 KB Flash hosts BLE firmware stacks and step-counting algorithms; 32 KB SRAM buffers BLE notifications. The DAC drives haptic feedback drivers for vibration motors. Operating from a single Li-ion cell (3.7 V nominal) via internal regulator or LDO, the MCU draws only 9 uA/MHz in active mode and <1 uA in Backup mode, enabling multi-day battery life. The exposed pad enables efficient thermal dissipation in enclosed wristband form factors.
Recommended
Smart Metering (Water / Gas / Electricity)
Metering applications require long battery life (10+ years on a primary cell), tamper detection, and reliable pulse counting. The ATSAMD20E18A-MNT's ultra-low-power Standby mode (<1 uA), RTC with calendar for time-of-use billing, and Event System that wakes the core from external interrupts without software intervention make it well suited for AMR/AMI endpoints. The 32 KB SRAM stores daily consumption logs and tamper-event timestamps. The 6 SERCOM ports connect to UART-based meter bus (M-Bus) modules and I2C EEPROM for non-volatile event history. The integrated 12-bit ADC reads battery voltage for low-battery alerts.
Recommended
Battery-Powered IoT Sensor Node (Sub-1 GHz / LoRa)
Sub-1 GHz IoT sensor nodes for agricultural, logistics, or smart-city deployments need multi-year battery life, low sleep current, and sufficient RAM for protocol stacks. The ATSAMD20E18A-MNT operates from a 3.6 V primary Li-SOCl2 cell with sub-microamp standby, while its 32 KB SRAM hosts LoRaWAN or Sigfox stacks when paired with a Semtech SX1276. The 12-bit ADC monitors soil moisture, temperature, or vibration sensors. The integrated RTC enables periodic wake-and-transmit cycles. Operating temperature -40C to +105C supports outdoor enclosures and industrial environments. The 6 SERCOM ports handle SPI radio, I2C sensor, and UART debug simultaneously.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD20E18A-MNT β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD20E17A-MNT | ATSAMC20E18A-MUT | ATSAMD20E16B-MN |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 32-VQFN (5x5 mm) | 32-VQFN (5x5 mm) - same | 32-VQFN (5x5 mm) - same | 32-VQFN (5x5 mm) - same |
| Flash Memory | 256 KB | 128 KB | 256 KB | 64 KB |
| SRAM | 32 KB | 16 KB | 32 KB | 8 KB |
| Maximum CPU Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Operating Voltage | 1.62 V to 3.63 V | 1.62 V to 3.63 V | 2.7 V to 5.5 V | 1.62 V to 3.63 V |
| USB | USB 2.0 FS Device | USB 2.0 FS Device | No (CAN-FD instead) | USB 2.0 FS Device |
| ADC Channels | 20 channels, 12-bit | 20 channels, 12-bit | 12 channels, 12-bit | 20 channels, 12-bit |
| SERCOM (I2C/SPI/UART) | 6 | 6 | 6 | 6 |
| Touch Controller (PTC) | 256-channel | 256-channel | 256-channel | 256-channel |
Key Differentiators
- Largest Flash in the SAM D20 32-VQFN family (vs ATSAMD20E16B-MN)
- Integrated USB 2.0 FS device controller (vs ATSAMC20E18A-MUT)
- Wide 1.62 V supply for direct battery operation (vs ATSAMC20E18A-MUT)
Design Notes
Estimated: for a 32-VQFN part with exposed pad, allocate at least 4 vias in the exposed pad (thermal vias, 0.3 mm drill, 0.5 mm pitch) connecting the EPAD to the inner ground plane. Per Microchip SAM D20 layout guidelines, the EPAD must be soldered to GND for thermal dissipation and electrical reference; an unsoldered EPAD raises junction temperature by 20-30 C at full load and can degrade ADC reference accuracy. Use 4-layer PCB with continuous ground pour under the QFN for best EMC and thermal performance.
Place one 100 nF decoupling capacitor (X7R, 10 V minimum) on every VDD and VDDANA pin, located within 3 mm of the pin and routed with wide traces to a low-impedance ground via. Add a bulk 4.7 uF tantalum or ceramic on the main VDD rail. For USB applications, add a 1 uF bulk on VDDIO and a 1 uF on VBUS. Per the Microchip datasheet, VDDANA should be tied to VDD or driven by a separate LDO for best ADC noise performance; never leave VDDANA floating.
Do not configure the SWD pins (PA30, PA31) as GPIO without disabling SWD in the NVM user row - this bricks debug access. Use the Atmel-ICE or MPLAB Snap debugger to unlock via full chip erase if needed. Also avoid leaving unused SERCOM pads floating in noisy environments; configure unused GPIO as output-low with internal pull disabled, or enable input buffer with internal pull-up to avoid spurious interrupts from the event system.
For USB 2.0 Full-Speed signals (PA11 = D-, PA12 = D+), keep trace lengths matched within 2 mm, route on the top layer with a continuous ground reference plane beneath, and avoid splitting the ground plane under USB traces. The integrated 48 MHz oscillator requires no external crystal for USB; the DFLL closes the USB clock accuracy loop automatically. If a crystal is used instead, place it within 5 mm of the XIN/XOUT pins and guard with a ground ring.
Estimated: the ATSAMD20E18A-MNT dissipates approximately 50 mW at full CPU load (48 MHz, all peripherals active, 3.3 V). The 32-VQFN has a typical theta_JA of 35 C/W with the EPAD soldered to a 1 square inch ground pour, giving a junction temperature rise of ~1.7 C - well within the 105 C operating limit. Industrial designs with ambient up to 85 C have ample margin without active cooling.
Compliance Information
RoHS and REACH compliant per Microchip 2026 product declaration. Not AEC-Q100 qualified - for automotive designs choose ATSAMxAEC variants. Halogen-free per JESD709. Conflict-minerals compliant per Microchip CMRT filings.
