ATSAML21E18B-AUT - ARM Cortex-M0+ 48MHz MCU | Microchip
MPN: ATSAML21E18B-AUT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.77 | $6.77 |
| 10 | $6.1 | $61.00 |
| 100 | $5.42 | $542.00 |
| 500 | $4.89 | $2,445.00 |
| 1,000 | $4.35 | $4,350.00 |
ATSAML21E18B-AUT Overview
A microcontroller (MCU) is a programmable system-on-chip that integrates a CPU core, Flash program memory, SRAM data memory, and peripherals into a single device. The Cortex-M0+ is ARM's smallest and most energy-efficient 32-bit core, optimized for cost-sensitive and ultra-low-power embedded applications. The SAM L21 family adds Microchip's proprietary power management techniques - SleepWalking, power domain gating, and ultra-low-power peripherals - that allow the CPU and peripherals to operate without always-on system clocks, dramatically extending battery life in IoT edge nodes.
Key features include a 2.46 CoreMark/MHz performance rating, 12-bit ADC and 12-bit DAC on-chip, multiple low-power modes (Active, Idle, Standby, Backup, Off), and built-in safety mechanisms such as Memory Protection Unit (MPU), Hardware CRC, and Windowed Watchdog Timer (WWDT). The device supports 1.62V to 3.63V supply voltage, integrated SERCOM serial communication, and up to 27 GPIO. An Event System enables inter-peripheral signaling without CPU wake-up, reducing active current further.
The ATSAML21E18B-AUT uses a Harvard-bus architecture with a 3-stage Cortex-M0+ pipeline, deterministic interrupt latency (12 cycles typical), and Single Wire Debug (SWD) interface. Memory is organized as 256KB Flash with ECC and 40KB SRAM, with 8KB low-power SRAM retained in Backup mode. The 12-bit ADC provides up to 1 MSPS with offset and gain error correction, and the 12-bit DAC supports 1 MSPS conversion rate - both run from the internal low-power analog reference.
Typical applications include battery-powered IoT sensor nodes, wearable health monitoring devices, smart metering, industrial wireless sensor networks, and home automation gateways. The combination of 256KB Flash, 40KB SRAM, and sub-µA sleep current suits the device to products requiring local intelligence plus multi-year battery life. The integrated AES engine and True Random Number Generator (TRNG) also enable secure connected-node designs.
When designing with this MCU, allocate pin function through the SAM L21 multiplexing table early in the schematic phase, because several peripheral functions share I/O lines. Always read the latest Microchip errata document before committing to the pinout, and size the decoupling network as recommended in the device datasheet to achieve the rated low-power numbers. The 200 nA Sleep-mode figure assumes the Backup SRAM is retained and the RTC is running from a 32.768 kHz crystal - losing either increases quiescent current.
This page synthesizes distributor pricing, drop-in compatible variants, and FuSa-design considerations not found in the manufacturer's overview document.
Drop-in alternatives for ATSAML21E18B-AUT — 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 ATSAML21E18B-AUT (same form factor and footprint) — differing in SRAM, Mounting Type, Package, Active Mode Current, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAML21E17B-AUT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAML21E16B-AUT
✅ Drop-In✓ In Stock
$2.65 / Unit
View Datasheet →ATSAML21E15B-AUT
✅ Drop-In✓ In Stock
$2.98 / Unit
View Datasheet →ATSAML21E18B-MUT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAML21E18B-AUT Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ (32-bit) |
| Maximum CPU Clock | 48 MHz |
| CoreMark Performance | 2.46 CoreMark/MHz |
| Program Flash Memory | 256 KB (256K x 8) |
| SRAM | 40 KB |
| Operating Voltage Range | 1.62 V to 3.63 V |
| Active Mode Current | <35 µA/MHz |
| Sleep Mode Current | 200 nA |
| ADC | 12-bit, up to 1 MSPS |
| DAC | 12-bit, up to 1 MSPS |
| Package | 32-pin TQFP (7x7 mm) |
| Mounting Type | Surface Mount (Tape & Reel) |
| Operating Temperature Range | -40C to +85C (industrial) |
| Debug Interface | Single Wire Debug (SWD) |
| Safety Features | Functional Safety (FuSa), MPU, CRC, WWDT |
| RoHS Status | Compliant |
| MSL Level | 3 (168 hours) |
| Series | SAM L21E (E variant, 32-pin) |
ATSAML21E18B-AUT Pin Configuration
| Pin 1 | PA02 — GPIO/SERCOM/I2C/ADC |
| Pin 2 | PA03 — GPIO/SERCOM/I2C/ADC |
| Pin 3 | PA04 — GPIO/SERCOM/I2C/ADC/VREFA |
| Pin 4 | PA05 — GPIO/SERCOM/I2C/ADC |
| Pin 5 | PA06 — GPIO/SERCOM/I2C/ADC |
| Pin 6 | PA07 — GPIO/SERCOM/I2C/ADC |
| Pin 7 | VDDIO — Digital I/O supply voltage |
| Pin 8 | GND — Ground |
| Pin 9 | PA08 — GPIO/SERCOM/I2C/ADC |
| Pin 10 | PA09 — GPIO/SERCOM/I2C/ADC |
| Pin 11 | PA10 — GPIO/SERCOM/I2C/ADC |
| Pin 12 | PA11 — GPIO/SERCOM/I2C/ADC |
| Pin 13 | PA14 — GPIO/SERCOM/I2C |
| Pin 14 | PA15 — GPIO/SERCOM/I2C |
| Pin 15 | PA16 — GPIO/SERCOM/I2C |
| Pin 16 | PA17 — GPIO/SERCOM/I2C |
| Pin 17 | PA18 — GPIO/SERCOM/I2C |
| Pin 18 | PA19 — GPIO/SERCOM/I2C |
| Pin 19 | PA22 — GPIO/SERCOM/I2C/ADC |
| Pin 20 | PA23 — GPIO/SERCOM/I2C/ADC |
| Pin 21 | PA24 — GPIO/SERCOM/I2C/USB_DM |
| Pin 22 | PA25 — GPIO/SERCOM/I2C/USB_DP |
| Pin 23 | GND — Ground |
| Pin 24 | VDD — Core supply voltage |
| Pin 25 | PA27 — GPIO/SERCOM/I2C/ADC |
| Pin 26 | RESET — Reset input (active-low) |
| Pin 27 | PA28 — GPIO/SERCOM/I2C |
| Pin 28 | PA30 — GPIO/SERCOM/SWDIO |
| Pin 29 | PA31 — GPIO/SERCOM/SWCLK |
| Pin 30 | PB02 — GPIO/SERCOM/ADC/VOUT |
| Pin 31 | PB03 — GPIO/SERCOM/ADC |
| Pin 32 | PB04 — GPIO/SERCOM/ADC/XIN32 |
Typical Applications
ATSAML21E18B-AUT is suitable for 7 applications: Battery-Powered IoT Sensor Nodes, Wearable Health Monitoring Devices, Smart Metering and Utility Endpoints, Industrial Wireless Sensor Networks, Home Automation and Smart Home Gateways, Remote Controls and Human-Machine Input Devices, Portable Medical Devices.
Battery-Powered IoT Sensor Nodes
The ATSAML21E18B-AUT is purpose-built for battery-powered wireless sensor nodes where multi-year battery life is critical. Its 200 nA Sleep current with full RAM retention and RTC running means a typical 2400 mAh CR2450 coin cell can sustain periodic sensor readings for 5-10 years. The Cortex-M0+ at 48 MHz handles LoRaWAN or BLE stack processing on wake, while SERCOM peripherals run I2C/SPI sensor interfaces. The 256 KB Flash accommodates full LoRaWAN 1.0.4 stack with margin, and 40 KB SRAM supports TLS handshake buffers.
Recommended
Wearable Health Monitoring Devices
Wearable health and fitness trackers benefit from the ATSAML21E18B-AUT's combination of Cortex-M0+ processing headroom, 12-bit ADC for bio-signal acquisition (heart rate, SpO2 photoplethysmography), and 12-bit DAC for stimulation outputs in TENS/EMS devices. The 35 µA/MHz active figure keeps average power low during 100 Hz sampling, while 200 nA Sleep mode preserves battery during idle wrist-worn periods. The 27 GPIO supports multiple sensor I/O, display SPI, and haptic feedback PWM channels simultaneously.
Recommended
Smart Metering and Utility Endpoints
Smart electricity, water, and gas meters rely on the ATSAML21E18B-AUT's Functional Safety (FuSa) library and IEC 60730 class B compliance support to pass regulatory certification. The 256 KB Flash stores metering firmware, calibration data, and wireless protocol stacks (Wireless M-Bus, NB-IoT). The 12-bit ADC with 1 MSPS captures instantaneous power measurements accurately, while the 32-bit Cortex-M0+ performs RMS calculations and tamper detection. Industrial temperature range (-40C to +85C) suits outdoor meter installations.
Recommended
Industrial Wireless Sensor Networks
Factory-floor wireless sensors and equipment monitors use the ATSAML21E18B-AUT to bridge Modbus/IO-Link sensors onto WirelessHART or IO-Link Wireless networks. The device's Event System routes peripheral interrupts without CPU wake-up, dramatically reducing average current in vibration-monitoring applications where accelerometers trigger only during abnormal events. The integrated AES-128 hardware engine encrypts industrial data without burdening the Cortex-M0+ core. Wide 1.62-3.63V supply tolerates 24V industrial bus rails with simple LDO regulation.
Recommended
Home Automation and Smart Home Gateways
Zigbee, Z-Wave, and Matter-compatible smart home devices leverage the ATSAML21E18B-AUT as the main controller for end nodes like door sensors, leak detectors, and battery-powered switches. The 200 nA Sleep current enables multi-year coin-cell operation, while 48 MHz Cortex-M0+ performance runs Zigbee 3.0 stack with margin. The 12-bit DAC provides audio feedback for voice-prompts or alarms, and the True Random Number Generator (TRNG) supports secure commissioning flows required by Matter specification.
Recommended
Remote Controls and Human-Machine Input Devices
Battery-powered remote controls, BLE key fobs, and human-machine interface (HMI) panels benefit from the ATSAML21E18B-AUT's low-power Cortex-M0+ performance and rich peripheral set. The 256 KB Flash stores complex button-mapping firmware and BLE peripheral libraries, while the 27 GPIO drives keypad matrices, IR transmitters, or capacitive touch sense channels. Sleep mode at 200 nA preserves coin-cell capacity across years of standby use, and the integrated 12-bit ADC reads analog joysticks or rotary encoders directly.
Recommended
Portable Medical Devices
Portable medical devices such as pulse oximeters, glucose meters, and nebulizers use the ATSAML21E18B-AUT for low-power bio-signal processing and regulated IEC 60601-1 compliance paths. The Functional Safety library supports firmware self-test routines required by IEC 60730 class B, and the 12-bit ADC captures diagnostic measurements with adequate resolution. Battery life extends significantly versus Cortex-M3 alternatives due to the sub-µA sleep current and SleepWalking peripheral architecture.
Recommended
Recommended Products Summary
Engineering reference data for ATSAML21E18B-AUT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAML21E17B-AUT | ATSAML21E16B-AUT | ATSAML21E15B-AUT |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 32-pin TQFP (7x7 mm) | 32-pin TQFP (7x7 mm) - same | 32-pin TQFP (7x7 mm) - same | 32-pin TQFP (7x7 mm) - same |
| Core | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz |
| Flash Memory | 256 KB | 256 KB | 256 KB | 32 KB (-87.5%) |
| SRAM | 40 KB | 32 KB (-20%) | 16 KB (-60%) | 4 KB (-90%) |
| Active Current | <35 µA/MHz | <35 µA/MHz | <35 µA/MHz | <35 µA/MHz |
| Sleep Current | 200 nA | 200 nA | 200 nA | 200 nA |
| Operating 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 |
Key Differentiators
- Largest SRAM in the SAM L21E 32-pin family (vs ATSAML21E17B-AUT)
- Maximum Flash density in the 32-pin TQFP package family (vs ATSAML21E15B-AUT)
- Sub-µA Sleep current with full SRAM retention (vs ATSAMD21E18A-AUT)
- Functional Safety (FuSa) library support for IEC 60730 (vs ATSAMG55J19B-AUT)
Design Notes
Estimated: The 200 nA Sleep-mode current assumes the Backup SRAM is retained and the RTC runs from a 32.768 kHz crystal. Disabling either subsystem increases quiescent current by approximately 1-3 µA. For battery-life estimation, use Microchip's Power Estimator (XPE) tool with the actual duty cycle rather than the datasheet minimum, because GPIO leakage and external LDO quiescent current are not included in the MCU figure.
Place the 1 µF VDD decoupling capacitor within 5 mm of the VDD pin, and add a 100 nF ceramic bypass as close as possible to the VDDIO pin per the SAM L21 datasheet summary. Use a 4-layer PCB with a solid ground plane under the QFP package to provide thermal dissipation and low-impedance return paths. The SWDIO and SWCLK pins should have 10 kΩ pull-up resistors to VDDIO for reliable debug interface operation.
Always read the Microchip SAM L21 errata document before finalizing the pinout - some SERCOM instances have known issues with specific I/O pins, and pin multiplexing tables change between silicon revisions. The NRST pin must be pulled high with at least a 10 kΩ resistor; leaving it floating causes intermittent resets during power-up. The 32.768 kHz crystal load capacitance must match the crystal specification or RTC accuracy suffers.
Estimated: For SERCOM peripherals running above 10 MHz, route clock and data signals with matched trace lengths (within 2 mm) and 50 Ω characteristic impedance using 4-layer stack-up. The USB DP/DM pins (PA24/PA25) require 90 Ω differential impedance matching - use Microchip's reference design layout as a starting point. Place the ESD protection diode within 5 mm of the connector.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified; for automotive applications refer to SAM V71/V70 families. IEC 60730 class B Functional Safety (FuSa) library available for safety-critical appliances.
