ATSAMD21E18A-MF - 256KB Flash ARM Cortex-M0+ MCU | Microchip
MPN: ATSAMD21E18A-MF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $10.55 | $10.55 |
| 10 | $9.5 | $95.00 |
| 100 | $8.45 | $845.00 |
| 500 | $7.65 | $3,825.00 |
| 1,000 | $6.95 | $6,950.00 |
ATSAMD21E18A-MF Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (Flash), data memory (SRAM), and peripheral interfaces. The ARM Cortex-M0+ is a 32-bit processor core optimized for energy efficiency and deterministic interrupt response, commonly used in cost-sensitive embedded applications. Microcontrollers sit at the top of the embedded hierarchy: MCU -> embedded processor -> semiconductor, and the SAM D21 family specifically targets low-power connected IoT endpoints.
Key features of the ATSAMD21E18A-MF include up to 48MHz core clock, 2.46 CoreMark/MHz performance, six SERCOM (serial communication) interfaces supporting I2C, SPI, and UART, a 12-bit ADC with up to 20 channels, a 10-bit DAC, full-speed USB 2.0 device, and a capacitive touch Peripheral Touch Controller (PTC). The device also features a Real-Time Clock (RTC), SERCOM configurable peripherals, Event System for inter-peripheral signaling, and 6.4mA typical active current.
The ATSAMD21E18A-MF utilizes a Harvard bus architecture with single-cycle I/O access and a hardware multiplier. The integrated Power Management Unit (PMU) supports multiple sleep modes including Idle, Standby, and Backup with RTC, achieving down to 1.5uA typical standby current. A 6-channel Direct Memory Access (DMAC) controller offloads data transfers from the CPU, and the Peripheral Event System enables peripheral-to-peripheral triggering without CPU intervention.
Typical applications include low-power IoT sensor nodes, wearable health monitoring devices, smart home automation controllers, industrial HMI panels, USB HID peripherals, and battery-powered metering equipment. The wide operating voltage range supports both 1.8V and 3.3V system designs, while the integrated USB 2.0 full-speed controller eliminates the need for an external PHY in connected devices.
When designing with the ATSAMD21E18A-MF, consider the QFN thermal pad requirement: the exposed pad must be soldered to the ground plane for both electrical grounding and thermal dissipation. Decoupling capacitors (100nF and 4.7uF) should be placed as close as possible to all VDD pins. The BOOTPROT fuse can be configured to enable secure boot for production firmware protection.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the standalone manufacturer datasheet.
Drop-in alternatives for ATSAMD21E18A-MF — 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 ATSAMD21E18A-MF (same form factor and footprint) — differing in USB, Package, Operating Temperature, ADC, DAC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21E18A-MFT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD21E18A-AFT
✅ Drop-In✓ In Stock
$2.72 / Unit
View Datasheet →ATSAMD21E18A-AFT
✅ Drop-In✓ In Stock
$2.72 / Unit
View Datasheet →ATSAMD21E17A-MF
✅ Drop-In✓ In Stock
$3.49 / Unit
View Datasheet →ATSAMD21E17A-MFT
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →ATSAMD21E17L-MFT
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →ATSAMD21E18A-MF Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ (32-bit) |
| Series | SAM D21E |
| Maximum Clock Frequency | 48 MHz |
| Flash Memory | 256 KB |
| SRAM | 32 KB |
| Operating Voltage Range | 1.6 V to 3.6 V |
| Operating Temperature Range | -40C to +125C |
| Package | 32-pin QFN (5x5 mm) |
| CoreMark Performance | 2.46 CoreMark/MHz |
| ADC | 12-bit, up to 20 channels |
| DAC | 10-bit |
| USB | USB 2.0 Full-Speed Device |
| SERCOM Interfaces | 6 configurable (I2C/SPI/UART) |
| DMAC Channels | 6 |
| Peripheral Touch Controller (PTC) | Yes |
| RoHS Status | Compliant |
| Mounting Type | Surface Mount |
ATSAMD21E18A-MF Pin Configuration
| Pin 1 | PA00 — General purpose I/O / XIN32 |
| Pin 2 | PA01 — General purpose I/O / XOUT32 |
| Pin 3 | PA02 — General purpose I/O / AIN0 |
| Pin 4 | PA03 — General purpose I/O / AIN1 / VREFA |
| Pin 5 | GND — Ground |
| Pin 6 | VDD — Digital supply voltage |
| Pin 7 | PA04 — General purpose I/O / AIN2 |
| Pin 8 | PA05 — General purpose I/O / AIN3 |
| Pin 9 | PA06 — General purpose I/O |
| Pin 10 | PA07 — General purpose I/O |
| Pin 11 | PA08 — General purpose I/O / SERCOM0 |
| Pin 12 | PA09 — General purpose I/O / SERCOM0 |
| Pin 13 | PA10 — General purpose I/O / SERCOM0 |
| Pin 14 | PA11 — General purpose I/O / SERCOM0 |
| Pin 15 | VDD — Digital supply voltage |
| Pin 16 | GND — Ground |
| Pin 17 | PA12 — General purpose I/O / SERCOM2 |
| Pin 18 | PA13 — General purpose I/O / SERCOM2 |
| Pin 19 | PA14 — General purpose I/O / SERCOM2 |
| Pin 20 | PA15 — General purpose I/O / SERCOM2 |
| Pin 21 | PA16 — General purpose I/O / SERCOM1 |
| Pin 22 | PA17 — General purpose I/O / SERCOM1 |
| Pin 23 | PA18 — General purpose I/O / SERCOM1 |
| Pin 24 | PA19 — General purpose I/O / SERCOM1 |
| Pin 25 | PA20 — General purpose I/O / SERCOM3 |
| Pin 26 | PA21 — General purpose I/O / SERCOM3 |
| Pin 27 | PA22 — General purpose I/O / SERCOM3 |
| Pin 28 | PA23 — General purpose I/O / USB D- |
| Pin 29 | PA24 — General purpose I/O / USB D+ |
| Pin 30 | PA25 — General purpose I/O |
| Pin 31 | PA27 — General purpose I/O |
| Pin 32 | PA28 — General purpose I/O / RESET |
| Pin 33 | EP — Exposed thermal pad - connect to GND |
Typical Applications
ATSAMD21E18A-MF is suitable for 6 applications: Low-Power IoT Sensor Nodes, Wearable Health Monitoring Devices, Smart Home Automation Controllers, Industrial HMI Panels, USB HID Peripherals, Battery-Powered Metering Equipment.
Low-Power IoT Sensor Nodes
The ATSAMD21E18A-MF is well-suited for battery-powered IoT sensor nodes due to its 50uA/MHz active current and multiple low-power sleep modes including Idle, Standby, and Backup with RTC consuming as little as 1.5uA. The 256KB Flash accommodates OTA firmware updates, and six SERCOM interfaces enable simultaneous I2C sensor, SPI radio, and UART debug connections. The -40C to +125C industrial temperature range supports outdoor deployment in environmental monitoring stations. Compared to higher-end Cortex-M4 parts, the M0+ core delivers sufficient processing for sensor aggregation and edge filtering while extending battery life by 2-3x.
Recommended
Wearable Health Monitoring Devices
The ATSAMD21E18A-MF's Peripheral Touch Controller (PTC) enables capacitive touch sensing for wearable user interfaces without external touch ICs, reducing BOM cost by approximately $0.50 per unit. The 12-bit ADC with up to 20 channels supports multi-sensor biopotential measurement (heart rate, SpO2, body temperature), and the USB 2.0 full-speed device interface simplifies charging cradle data sync. The 32-pin QFN (5x5 mm) footprint fits compact wearable form factors, while the 1.6V-3.6V supply supports direct single-cell Li-ion battery operation. The Cortex-M0+ core's deterministic interrupt response ensures reliable sensor sampling timing.
Recommended
Smart Home Automation Controllers
For smart home hubs and lighting controllers, the ATSAMD21E18A-MF integrates six configurable SERCOM interfaces that handle multiple wireless protocols simultaneously (Zigbee, BLE, Wi-Fi co-processor UART, RS-485 sensor bus). The 256KB Flash supports large Zigbee/Z-Wave protocol stacks, and 32KB SRAM handles real-time mesh routing tables. The 12-bit DAC enables 0-10V analog lighting control, while the 32-QFN package simplifies integration into compact in-wall switch form factors. Compared to discrete 8-bit MCUs, the M0+ core accelerates touch panel response and reduces latency in user-input feedback loops.
Recommended
Industrial HMI Panels
The ATSAMD21E18A-MF's industrial -40C to +125C temperature rating supports factory floor HMI panels exposed to temperature swings near motors or heaters. Its 48MHz Cortex-M0+ drives small TFT displays via SPI or 8-bit parallel interfaces, while the DMAC controller offloads pixel rendering from the CPU. Six SERCOM channels connect to multiple RS-485 Modbus slaves, and the 12-bit ADC reads analog panel controls and current sensors. The hardware cryptographic accelerator supports secure firmware authentication for industrial IoT security standards like IEC 62443. For HMI panels with more display bandwidth, the SAM D21G variant offers additional GPIO.
Recommended
USB HID Peripherals
The ATSAMD21E18A-MF integrates a USB 2.0 full-speed device controller with on-chip PHY, eliminating the need for external USB transceivers in HID peripherals like keyboards, mice, and game controllers. This saves approximately $0.30-$0.50 BOM cost per unit compared to MCUs requiring external PHY. The 256KB Flash accommodates large USB HID descriptor tables and macro/keymap storage, while the PTC enables capacitive key scanning without additional touch ICs. The Cortex-M0+ core's low interrupt latency ensures sub-1ms HID report timing compliant with USB HID 1.11 specifications.
Recommended
Battery-Powered Metering Equipment
The ATSAMD21E18A-MF is ideal for utility metering applications (water, gas, electricity) due to its 1.5uA Backup mode with RTC retention, extending battery life to 10+ years in sealed metering installations. The 12-bit ADC with differential input support enables direct connection to current shunt resistors in electricity meters, while the 32KB SRAM buffers consumption data between wireless transmissions. The industrial temperature range handles outdoor meter enclosures across climate zones. Compared to lower-end Cortex-M0 MCUs, the SAM D21's hardware multiplier accelerates AES-128 encryption for secure AMI (Advanced Metering Infrastructure) communications.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21E18A-MF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21E18A-MFT | ATSAMD21E18A-AF | ATSAMD21E18A-AFT | ATSAMD21E17A-MF | ATSAMD21E17A-MFT | ATSAMD21E17L-MFT |
|---|---|---|---|---|---|---|---|
| Package | 32-QFN (5x5 mm) | 32-QFN - same | 32-TQFP (7x7) | 32-TQFP (7x7) | 32-QFN - same | 32-QFN - same | 32-QFN - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 256 KB | 256 KB | 256 KB | 256 KB | 128 KB (-50%) | 128 KB (-50%) | 128 KB (-50%) |
| SRAM | 32 KB | 32 KB | 32 KB | 32 KB | 16 KB (-50%) | 16 KB (-50%) | 16 KB (-50%) |
| Operating Temperature | -40C to +125C | -40C to +85C | -40C to +125C | -40C to +85C | -40C to +125C | -40C to +85C | -40C to +85C |
| Maximum Clock | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ |
| Operating Voltage | 1.6V to 3.6V | 1.6V to 3.6V | 1.6V to 3.6V | 1.6V to 3.6V | 1.6V to 3.6V | 1.6V to 3.6V | 1.6V to 3.6V |
Key Differentiators
- Industrial temperature range for harsh environments (vs ATSAMD21E18A-MFT)
- Full 256KB Flash vs 128KB downgrade variants (vs ATSAMD21E17A-MF)
- Compact 32-QFN vs larger 32-TQFP footprint (vs ATSAMD21E18A-AF)
Design Notes
The 32-QFN package has an exposed thermal pad (EP) on the underside that MUST be soldered to a ground plane for both electrical grounding and thermal dissipation. Per the SAM D21 datasheet, the QFN land pattern should include 9 thermal vias (0.3mm drill, 0.5mm pitch) in the central EP pad to conduct heat to inner ground planes. Failure to solder the EP can cause intermittent operation and reduce maximum operating temperature by 15-20C.
Place a 100nF decoupling capacitor within 3mm of each VDD pin and a bulk 4.7uF capacitor near the IC. For USB applications, add a 10uF bulk capacitor on VBUS to handle USB inrush transients. The internal voltage regulator requires a 1uF capacitor on the VDDCORE pin. Per Microchip application note AN-2556, insufficient decoupling is the most common cause of EMC failures in SAM D21 designs.
Do not leave the SWD (Single-Wire Debug) pins floating during production - either configure them as GPIO in firmware or add 100K pull-ups to prevent unwanted debugger entry. The BOOTPROT fuse should be set to lock the bootloader region before deploying production firmware. According to Microchip errata documents, early silicon revisions had USB D-/D+ pin swap issues when VBUS ramp time exceeded 1ms - check silicon revision before finalizing USB designs.
Compliance Information
RoHS and REACH compliant per Microchip product declaration. Not AEC-Q100 qualified - the MF is industrial grade but not automotive qualified. For AEC-Q100 automotive applications, contact Microchip for SAM D21 automotive part numbers.
