ATSAMD20E18A-AU - ARM Cortex-M0+ MCU 256KB Flash 32-TQFP | Microchip
MPN: ATSAMD20E18A-AU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.66 | $3.66 |
| 10 | $3.29 | $32.90 |
| 100 | $2.95 | $295.00 |
| 500 | $2.69 | $1,345.00 |
| 1,000 | $2.41 | $2,410.00 |
| 3,000 | $2.18 | $6,540.00 |
ATSAMD20E18A-AU Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, memory (Flash for program code and SRAM for data), and a rich set of peripherals on one die. The Cortex-M0+ sits at the lowest-power end of the ARM Cortex-M family tree, optimized for deterministic interrupt response at minimal energy cost. MCUs belong to the broader embedded controller hierarchy - faster than 8/16-bit legacy microcontrollers but simpler than microprocessors, and form a subset of integrated circuits used in virtually all digital products.
Key features of the ATSAMD20E18A-AU include the Microchip proprietary Atmel START / MPLAB X IDE support, a 32 KB SRAM with a tightly-coupled bus for low-latency access, a full-speed USB 2.0 device with on-chip transceiver, and a peripheral touch controller (PTC) supporting capacitive buttons, sliders, and wheels. The integrated sleepwalking peripheral event system allows peripherals to wake the core only when needed, enabling deep Sleep mode currents below 10 µA.
The architecture uses a single 32-bit AHB-Lite bus with a separate bridge for low-power peripherals, and the Cortex-M0+ implements the ARMv6-M Thumb instruction set. A hardware multiplier (32-bit result in one cycle) and configurable NVIC (Nested Vectored Interrupt Controller) with up to 32 IRQs give the part real-time responsiveness uncommon in entry-level MCUs.
Typical applications include home automation nodes, low-cost consumer devices, smart energy metering, industrial sensor hubs, and capacitive-touch user interfaces. The wide 1.62 V to 3.63 V range supports direct connection to single-cell Li-ion (3.7 V nominal) and 3.3 V regulated rails without level shifters.
When designing with this part, decouple VDDIN and VDDCORE with 100 nF plus 4.7 µF bulk capacitors placed within 5 mm of the pins. Use the SERCOM peripheral (not legacy USART/SPI/I2C) and route D+ / D- differential traces with 90 Ω impedance if USB is enabled.
This page synthesizes distributor pricing from DigiKey, Mouser, Heisener, LCSC, and Octopart; same-package drop-in alternatives from the Microchip SAMD20 family; and practical design notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATSAMD20E18A-AU — 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-AU (same form factor and footprint) — differing in ADC, Package, DAC, Peripheral Touch Controller (PTC), SRAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD20E17A-AU
✅ Drop-In✓ In Stock
$2.5 / Unit
View Datasheet →ATSAMD20E16B-AU
✅ Drop-In✓ In Stock
$1.84 / Unit
View Datasheet →ATSAMD20E18A-AUT
✅ Drop-In✓ In Stock
$2.78 / Unit
View Datasheet →ATSAMD21E18A-AU
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMC21E17A-AUT
✅ Drop-In✓ In Stock
$2.45 / Unit
View Datasheet →ATSAMD20E18A-AU Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ |
| Core Width | 32-bit |
| Maximum Clock Frequency | 48 MHz |
| Program Memory Size (Flash) | 256 KB (256K x 8) |
| RAM Size | 32 KB |
| Supply Voltage Range | 1.62 V to 3.63 V |
| Operating Temperature Range | -40 C to +85 C (industrial) |
| Package | 32-TQFP 7x7 mm |
| Mounting Type | Surface Mount |
| Number of I/O Pins | 26 (max) |
| ADC | 12-bit, 350 ksps, up to 14 channels |
| DAC | 10-bit, 350 ksps, 1 channel |
| Communication Interfaces | SERCOM (UART/SPI/I2C) x6, USB 2.0 Full-Speed Device, I2S |
| Peripheral Touch Controller (PTC) | Yes (buttons, sliders, wheels) |
| MSL Level | 3 (168 hours) |
| RoHS Status | Compliant |
| Lead-Free / Halogen-Free | Lead-free, Halogen-free per Microchip |
ATSAMD20E18A-AU Pin Configuration
| Pin 1 | PA03 — GPIO / ADC input / SERCOM pad |
| Pin 2 | PA04 — GPIO / ADC input / SERCOM pad |
| Pin 3 | PA05 — GPIO / ADC input / SERCOM pad |
| Pin 4 | PA06 — GPIO / ADC input / SERCOM pad |
| Pin 5 | PA07 — GPIO / ADC input / SERCOM pad |
| Pin 6 | VDDIN — Main power supply input (1.62 V to 3.63 V) |
| Pin 7 | GND — Ground |
| Pin 8 | PA08 — GPIO / NTC input / SERCOM pad (shared with XOSC) |
| Pin 9 | PA09 — GPIO / SERCOM pad (shared with XOSC) |
| Pin 10 | PA10 — GPIO / SERCOM pad |
| Pin 11 | PA11 — GPIO / SERCOM pad |
| Pin 12 | VDDCORE — Internal LDO output (decouple with 1uF + 100nF) |
| Pin 13 | PA14 — GPIO / SERCOM pad |
| Pin 14 | PA15 — GPIO / SERCOM pad |
| Pin 15 | PA16 — GPIO / SERCOM pad (I2S MCLK) |
| Pin 16 | PA17 — GPIO / SERCOM pad (I2S FS) |
| Pin 17 | PA18 — GPIO / SERCOM pad (I2S BCLK / XOUT32) |
| Pin 18 | PA19 — GPIO / SERCOM pad (I2S SDIN / XIN32) |
| Pin 19 | PA20 — GPIO / SERCOM pad |
| Pin 20 | PA21 — GPIO / SERCOM pad |
| Pin 21 | PA22 — GPIO / SERCOM pad |
| Pin 22 | PA23 — GPIO / SERCOM pad / USB D- |
| Pin 23 | PA24 — GPIO / SERCOM pad / USB D+ |
| Pin 24 | PA25 — GPIO / SERCOM pad |
| Pin 25 | PA27 — GPIO / SERCOM pad |
| Pin 26 | RESET — Reset input (active low, internal pull-up) |
| Pin 27 | PA28 — GPIO / SERCOM pad |
| Pin 28 | PA30 — SWDIO - Serial Wire Debug I/O |
| Pin 29 | PA31 — SWCLK - Serial Wire Debug Clock |
| Pin 30 | VDDIO — I/O supply (typically tied to VDDIN) |
| Pin 31 | GND — Ground |
| Pin 32 | PA02 — GPIO / ADC input / SERCOM pad |
Typical Applications
ATSAMD20E18A-AU is suitable for 6 applications: Home Automation Nodes, Capacitive Touch User Interfaces, Smart Energy Metering, Industrial Sensor Hubs, USB HID Consumer Devices, Wearables and Fitness Bands.
Home Automation Nodes
The ATSAMD20E18A-AU fits home automation sensor and actuator nodes because its 256 KB Flash holds Zigbee or Matter application stacks alongside custom firmware, while the 32 KB SRAM supports real-time protocol buffers. The 1.62 V to 3.63 V supply range allows direct connection to single-cell Li-ion batteries, eliminating external regulators. Its integrated Peripheral Touch Controller (PTC) supports capacitive buttons and sliders for wall switches without external touch ICs. The 48 MHz Cortex-M0+ core provides the deterministic interrupt response needed for protocol timing, and the six SERCOM modules handle multiple bus interfaces (I2C sensors, SPI radios, UART debug) concurrently. Deep Sleep currents below 10 uA extend battery life in always-on wireless sensors.
Recommended
Capacitive Touch User Interfaces
The ATSAMD20E18A-AU excels in capacitive touch products thanks to its on-chip Peripheral Touch Controller (PTC), which supports buttons, sliders, wheels, and proximity sensing without external touch ICs. The 12-bit 350 ksps ADC provides additional analog sampling for sliders and lighting feedback, while the 26 GPIO drive LEDs and relays directly. Six SERCOM channels let the same MCU drive an I2C display, an SPI LED driver, and a UART-based Bluetooth module simultaneously. The Cortex-M0+ handles touch scanning and gesture recognition at 48 MHz with minimal interrupt jitter. Combined with the 256 KB Flash, gesture libraries and custom UI logic fit comfortably alongside application code.
Recommended
Smart Energy Metering
The ATSAMD20E18A-AU suits single-phase and three-phase smart energy meters because its 12-bit 350 ksps ADC simultaneously samples voltage and current channels with deterministic timing. The 32 KB SRAM holds metering buffers, RMS calculations, and tamper-detection state without external memory, while the 256 KB Flash stores the metering application, calibration tables, and DLMS/COSEM or Modbus stacks. The integrated 10-bit DAC supports calibration signal generation and analog front-end trimming. Six SERCOM channels interface to a metrology AFE, an external EEPROM for billing records, and an optical UART port for utility technicians. The industrial -40 C to +85 C temperature range covers outdoor meter enclosure requirements.
Recommended
Industrial Sensor Hubs
The ATSAMD20E18A-AU is ideal for industrial 4 mA to 20 mA sensor hubs because its wide 1.62 V to 3.63 V supply tolerates loop-powered and 24 V rail topologies after regulation. The 12-bit ADC provides 14 channels of analog input for thermocouples, RTDs, and bridge sensors, while the 6 SERCOM channels aggregate I2C sensors (temperature, pressure) and SPI ADCs. The 32 KB SRAM supports running Modbus RTU protocol stacks and circular data buffers simultaneously, with the 256 KB Flash holding application logic, calibration constants, and firmware update images. The Cortex-M0+ deterministic interrupt response handles Modbus timing without jitter. Industrial temperature grade -40 C to +85 C suits factory floor enclosures.
Recommended
USB HID Consumer Devices
The ATSAMD20E18A-AU targets USB HID consumer devices because of its integrated full-speed USB 2.0 device with on-chip transceiver, eliminating the need for external PHY chips. The 48 MHz Cortex-M0+ easily handles USB HID class drivers, keyboard/mouse scan matrices, and consumer-control descriptors within its 256 KB Flash budget. The 32 KB SRAM supports HID report buffers and USB endpoint FIFOs with headroom for custom command processing. Six SERCOM channels enable simultaneous UART debug, SPI external flash, and I2C peripheral expansion. The industrial -40 C to +85 C temperature range supports ruggedized input devices. Direct 3.3 V USB bus-powered operation simplifies PCB design significantly.
Recommended
Wearables and Fitness Bands
The ATSAMD20E18A-AU fits fitness wearables and wearables thanks to its Cortex-M0+ core's exceptional energy efficiency and the SAM D20 sleepwalking peripheral event system. With deep Sleep currents below 10 uA and the ability to wake only on sensor thresholds, the MCU maximizes battery life in always-on heart-rate and motion-tracking applications. The 256 KB Flash holds BLE stack or proprietary RF protocols plus sensor fusion algorithms, while the 32 KB SRAM supports motion buffer and display refresh. The 12-bit ADC samples PPG (photoplethysmography) optical sensor channels for heart rate, and 6 SERCOM interfaces drive an I2C IMU, SPI OLED display, and UART BLE module. Direct 3.7 V Li-ion operation matches typical wearable battery stacks.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD20E18A-AU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD20E17A-AU | ATSAMD20E16B-AU | ATSAMD20E18A-AUT | ATSAMD21E18A-AU | ATSAMC21E17A-AUT |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 32-TQFP (7x7 mm) | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ |
| Flash | 256 KB | 128 KB (-50%) | 64 KB (-75%) | 256 KB (same) | 256 KB (same) | 128 KB (-50%) |
| SRAM | 32 KB | 16 KB (-50%) | 8 KB (-75%) | 32 KB (same) | 32 KB (same) | 16 KB (-50%) |
| Max Clock Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Supply 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 | 2.7 V to 5.5 V |
| USB 2.0 FS Device | Yes (integrated) | Yes | Yes | Yes | Yes | Yes |
| CAN-FD Support | No | No | No | No | No | Yes (SAMC21 adds CAN-FD) |
| Temperature Range | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +125 C (extended) |
Key Differentiators
- Maximum Flash density in SAMD20E 32-TQFP family (vs ATSAMD20E17A-AU)
- Integrated USB 2.0 Full-Speed with on-chip transceiver (vs ATSAMC21E17A-AUT)
- True Cortex-M0+ low-power sleepwalking architecture (vs ATSAMD20E16B-AU)
Design Notes
Decouple VDDIN (pin 6) with a 100 nF ceramic plus a 4.7 uF bulk capacitor placed within 5 mm of the pin. VDDCORE (pin 12) requires a 1 uF X7R plus a 100 nF high-frequency bypass. The SAM D20 internal LDO regulator can operate in LDO or DC-DC switching mode (set by external inductor); LDO mode is recommended for low-noise analog designs and simplifies EMI. Avoid routing noisy switching signals near VDDIO and VDDCORE traces.
For USB applications, route the D+ (PA24, pin 24) and D- (PA23, pin 23) traces as a 90 ohm differential pair with length matching to within 2 mm. Place a 27 ohm series resistor on each line close to the MCU if required by USB certification testing. Keep the USB cable-side common-mode choke and ESD protection array within 5 mm of the connector. The ATSAMD20E18A-AU's integrated USB pull-up resistor eliminates the need for an external 1.5K pull-up on D-.
Do not configure the SWDIO (PA30, pin 28) and SWCLK (PA31, pin 29) pins as GPIO before programming - they default to SWD mode after reset, but lockout can occur if BOOTPROT settings are incorrectly flashed. The PA30/PA31 pins must remain accessible for debugger connectivity in production. If SWD pins must be reused, program the GPNVM bits via Atmel START or MPLAB X to disable SWD permanently. The reset pin (pin 26) requires an external 10 kohm pull-up and a 100 nF decoupling capacitor for stable operation.
The 32-TQFP package has a thermal resistance (theta_JA) of approximately 55 C/W when mounted on a standard 4-layer JEDEC test board. At industrial ambient 85 C with full 48 MHz CPU and all peripherals active, the part dissipates well under 100 mW, so junction temperature rise is negligible (<5 C). For applications requiring continuous USB VBUS operation or high GPIO drive current, ensure adequate copper pour on the thermal pad area to spread heat. No external heatsink is required for typical embedded designs.
Compliance Information
RoHS and REACH compliance per Microchip product page. Industrial temperature grade -40C to +85C. Not AEC-Q100 qualified - choose SAM C20/C21 automotive variants for vehicle applications. Lead-free and halogen-free per Microchip environmental compliance documentation.
