ATSAML21E15B-MNT - 32KB Flash Cortex-M0+ MCU 32-VQFN | Microchip
MPN: ATSAML21E15B-MNT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.95 | $2.95 |
| 10 | $2.66 | $26.60 |
| 100 | $2.37 | $237.00 |
| 500 | $2.13 | $1,065.00 |
| 1,000 | $1.9 | $1,900.00 |
ATSAML21E15B-MNT Overview
An ARM Cortex-M0+ microcontroller is a 32-bit RISC processor core designed for energy-efficient embedded applications. The Cortex-M0+ sits within the broader hierarchy: Cortex-M0+ -> ARM Cortex-M family -> 32-bit MCU -> embedded microcontroller -> semiconductor. The SAM L21E family extends this with Microchip's proprietary picoPower technology, multiple low-power operating modes, and an integrated Peripheral Touch Controller (PTC) for capacitive touch sensing, enabling human-machine interfaces without external components.
Key differentiating features include 12-bit ADC and 12-bit DAC, full-speed USB 2.0 device support, SERCOM (serial communication) interfaces configurable as UART/SPI/I2C, a Real-Time Clock (RTC) with calendar, and 24 wake-up sources via the Event System. Functional Safety (FuSa) variants (suffix A) include enhanced diagnostics for IEC 60730 Class B compliance, making the family suitable for white goods and safety-critical applications. The wide 1.6V to 3.6V operating range supports single-cell Li-ion, two-AA, and coin-cell battery topologies.
Typical applications include battery-powered IoT sensor nodes, wearable health monitors, smart home wireless endpoints (BLE/Zigbee co-processor hosts), capacitive touch user interfaces, and industrial sensor transmitters. The combination of sub-µA sleep current and fast wake-up (1.5 µs typical from standby) makes it ideal for duty-cycled edge devices where total energy budget dominates battery life calculations.
When designing with the SAM L21E, select the appropriate sleep mode (Idle, Standby, Backup) based on required peripheral availability - Standby preserves RTC and 1.5 µA wake-up, while Backup drops to ~200 nA but loses RAM retention. Always place a 1 µF + 100 nF decoupling pair within 3 mm of the VDD pins, and use the brown-out detector (BOD33) at 2.78V minimum for reliable 3.3V operation.
This page synthesizes distributor pricing, same-family drop-in alternatives, and practical low-power design notes not found in the standalone manufacturer datasheet.
Drop-in alternatives for ATSAML21E15B-MNT — 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 ATSAML21E15B-MNT (same form factor and footprint) — differing in Package, ADC, Sleep Mode Current, Active Mode Current, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAML21E16B-MNT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAML21E15B-AUT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.98 / Unit
View Datasheet →ATSAML10E15A-MUT
✅ Drop-In✓ In Stock
$2.74 / Unit
View Datasheet →ATSAML10E15A-AU
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$1.92 / Unit
View Datasheet →ATSAML11E15A-MU
✅ Drop-In✓ In Stock
$1.55 / Unit
View Datasheet →ATSAML11E16A-MFTKPH
✅ Drop-In✓ In Stock
$3.32 / Unit
View Datasheet →ATSAME53J19A-MFT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$6.45 / Unit
View Datasheet →ATSAML21E15B-MNT Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ |
| Core Count | Single-core 32-bit |
| Maximum Clock Frequency | 48 MHz |
| Flash Memory | 32 KB (32K x 8) |
| SRAM | 4 KB |
| Operating Voltage Range | 1.6 V to 3.6 V |
| Active Mode Current | <35 µA/MHz |
| Sleep Mode Current | 200 nA |
| ADC | 12-bit |
| DAC | 12-bit |
| USB | Full-speed USB 2.0 Device |
| Operating Temperature Range | -40°C to +85°C |
| Package | 32-VQFN (5x5 mm) with exposed pad |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Carrier Type | Tape & Reel |
ATSAML21E15B-MNT Pin Configuration
| Pin 1 | PA00 — General-purpose IO / SERCOM pad |
| Pin 2 | PA01 — General-purpose IO / SERCOM pad |
| Pin 3 | PA02 — AIN0 (Analog input 0) |
| Pin 4 | PA03 — AIN1 / VREFA (ADC reference) |
| Pin 5 | GND — Ground |
| Pin 6 | VDD — Digital supply voltage |
| Pin 7 | PA04 — AIN2 / DAC output |
| Pin 8 | PA05 — AIN3 |
| Pin 9 | PA06 — AIN4 / SERCOM |
| Pin 10 | PA07 — AIN5 / SERCOM |
| Pin 11 | PA08 — AIN6 / SERCOM (I2C) |
| Pin 12 | PA09 — AIN7 / SERCOM (I2C) |
| Pin 13 | PA10 — AIN8 / SERCOM |
| Pin 14 | PA11 — USB D- |
| Pin 15 | PA12 — USB D+ |
| Pin 16 | PA13 — SWDIO (programming) |
| Pin 17 | PA14 — SWCLK (programming) |
| Pin 18 | PA15 — SERCOM / GPIO |
| Pin 19 | PA16 — SERCOM / GPIO |
| Pin 20 | PA17 — SERCOM / GPIO |
| Pin 21 | PA18 — SERCOM / GPIO |
| Pin 22 | PA19 — SERCOM / GPIO |
| Pin 23 | PA20 — SERCOM / GPIO |
| Pin 24 | PA21 — SERCOM / GPIO |
| Pin 25 | PA22 — SERCOM / GPIO |
| Pin 26 | PA23 — SERCOM / GPIO |
| Pin 27 | PA24 — USB SOF / GPIO |
| Pin 28 | PA25 — GPIO |
| Pin 29 | PA27 — RESET (active low) |
| Pin 30 | PA28 — GPIO / XIN (crystal) |
| Pin 31 | PA29 — GPIO / XOUT (crystal) |
| Pin 32 | PA30 — GPIO / SWD reset |
| Pin EP | EP — Exposed thermal pad - connect to GND |
Typical Applications
ATSAML21E15B-MNT is suitable for 6 applications: Battery-Powered IoT Sensor Nodes, Wearable Health Monitors, Capacitive Touch User Interfaces, Smart Home Wireless Endpoints, Industrial Sensor Transmitters, USB-Powered Consumer Devices.
Battery-Powered IoT Sensor Nodes
The ATSAML21E15B-MNT is well-suited for duty-cycled IoT sensor endpoints that spend most of their time in low-power states and only wake briefly to take measurements and transmit data. With 200 nA Sleep current and <35 µA/MHz active current, the device can run for years on a single CR2032 coin cell when duty-cycled at 0.1%. The Cortex-M0+ core at 48 MHz executes sensor reads, filtering, and packet preparation within milliseconds, after which the SERCOM interfaces (configurable as SPI for sensors or UART for radio modules) handle communication. The integrated 12-bit ADC captures analog sensor data without external components, and the RTC with calendar enables accurate sleep/wake scheduling. Recommended companion parts: ATSAMR34J18B (LoRa radio module) for long-range, or RN4871 for BLE connectivity.
Recommended
Wearable Health Monitors
The ATSAML21E15B-MNT's picoPower architecture is ideal for wearable health and fitness devices where battery life, size, and weight are critical constraints. The 32-VQFN (5x5 mm) package fits compact wrist-worn form factors, while the 200 nA Sleep current with RTC retention enables always-on step counting and heart-rate monitoring on coin-cell batteries. The integrated 12-bit ADC captures bioelectric signals (PPG, ECG) and battery voltage, while the on-chip temperature sensor provides calibration references. The Peripheral Touch Controller (PTC) supports capacitive buttons and sliders for user input without mechanical switches, improving water resistance. Active current of 35 µA/MHz allows continuous sensor sampling at modest processing load without draining the battery during exercise tracking.
Recommended
Capacitive Touch User Interfaces
The ATSAML21E15B-MNT integrates Microchip's Peripheral Touch Controller (PTC), supporting up to 256 channel capacitive touch sensing with hardware-accelerated acquisition and noise filtering. This makes the device a strong fit for white goods control panels, industrial HMIs, and consumer appliances requiring reliable touch buttons or sliders in noisy environments. The Cortex-M0+ core handles PTC data processing and gesture recognition while the Event System routes wake-up events directly from touch electrodes, allowing the MCU to stay in deep sleep until a user touches the panel. The functional-safety (-A) variants provide IEC 60730 Class B diagnostics for appliance safety compliance, eliminating the need for external watchdogs in many designs.
Recommended
Smart Home Wireless Endpoints
For smart home devices such as door/window sensors, occupancy detectors, and battery-powered switches, the ATSAML21E15B-MNT provides the processing and power management needed to host a wireless co-processor over UART or SPI. The full-speed USB 2.0 device interface enables direct commissioning via USB when needed, while the multiple SERCOM interfaces (configurable as I2C/SPI/UART) connect to environmental sensors and radio modules. Sleep currents under 1 µA with RTC retention allow multi-year operation on 2xAA batteries, and the Event System provides 24 wake-up sources including GPIO, RTC compare, and ADC window compare for autonomous sensor triggering without CPU intervention.
Recommended
Industrial Sensor Transmitters
The ATSAML21E15B-MNT suits industrial 4-20 mA loop-powered sensor transmitters and remote monitoring nodes that must operate reliably from limited supply currents. The 1.6V to 3.6V operating range accommodates direct regulation from loop or battery sources, and the 12-bit ADC with PGA (Programmable Gain Amplifier) accepts low-level sensor signals (thermocouples, strain gauges) without external instrumentation amplifiers. The wide -40°C to +85°C operating temperature range (or -40°C to +105°C for -A suffix parts) supports industrial environments. Functional Safety variants add self-test diagnostics for IEC 61508 SIL-2 capable designs, while the 32-VQFN package enables compact field-mount enclosures.
Recommended
USB-Powered Consumer Devices
The ATSAML21E15B-MNT's integrated full-speed USB 2.0 device controller enables designers to build USB-connected peripherals (HID devices, data loggers, sensors) without an external USB interface chip. The 48 MHz Cortex-M0+ core handles USB protocol stacks, sensor reads, and HID report generation in a single chip, reducing BOM cost and PCB area. Operating directly from USB 5V through an internal 3.3V regulator (when present), the device simplifies USB dongle designs. The 32-VQFN package fits in compact USB stick form factors, while Sleep current under 1 µA supports USB suspend compliance for battery-powered USB devices.
Recommended
Recommended Products Summary
Engineering reference data for ATSAML21E15B-MNT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAML21E16B-MNT | ATSAML10E15A-MUT | ATSAML11E15A-MU |
|---|---|---|---|---|
| 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 |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ (with TrustZone-M) |
| Max Clock Frequency | 48 MHz | 48 MHz | 32 MHz | 48 MHz |
| Flash Memory | 32 KB | 64 KB | 32 KB | 32 KB |
| SRAM | 4 KB | 8 KB | 4 KB | 8 KB |
| Operating Voltage | 1.6V to 3.6V | 1.6V to 3.6V | 1.62V to 3.63V | 1.62V to 3.63V |
| Sleep Current | 200 nA | 200 nA | 100 nA (lower power) | 200 nA |
| USB Support | Full-speed USB 2.0 Device | Full-speed USB 2.0 Device | No USB | Full-speed USB 2.0 Device |
Key Differentiators
- Ultra-low Sleep current with RTC retention (vs ATSAMD21E15L-MNT)
- Integrated Peripheral Touch Controller (PTC) (vs ATSAM10E15A-MUT)
- Functional Safety (FuSa) variant availability (vs ATSAML10E15A-MUT)
Design Notes
The SAM L21E provides multiple low-power modes: Idle (~3 µA), Standby (1.5 µA with RTC), and Backup (200 nA without RAM retention). For battery-life calculations, model the duty cycle accurately - average current = (active_current × t_active + sleep_current × t_sleep) / total_period. For a typical IoT sensor that wakes for 5 ms every 10 seconds, average current is dominated by sleep current; verify the wake-up time (~1.5 µs from standby) does not exceed your timing budget. Enable the BOD33 (brown-out detector) at the 2.78V minimum level for reliable 3.3V operation.
Place a 1 µF X7R ceramic decoupling capacitor within 3 mm of each VDD pin, paired with a 100 nF X7R for high-frequency noise. The 32-VQFN exposed thermal pad MUST be soldered to a ground copper pour of at least 25 mm² for thermal dissipation and electrical ground reference. Use a 4-layer PCB with a dedicated ground plane for best EMI/EMC performance; signal traces crossing the thermal pad area should be avoided to prevent shorts during reflow. The USB D+/D- traces must be length-matched within 150 mil and routed with 90-ohm differential impedance for USB compliance.
Do not skip configuration of the NVM user rows (BOOTPROT, EEPROM emulation settings) before locking the device - recovery requires a full chip erase. The SERCOM pads are highly multiplexed; ensure pin assignments do not conflict with the USB D+/D- on PA11/PA12 if USB is enabled. When using the integrated PTC for capacitive touch, calibrate the touch sensitivity per PCB layout - touch sensitivity varies with overlay thickness and trace capacitance. Always enable the WDT (watchdog timer) in safety-critical or unattended applications.
Compliance Information
RoHS and REACH compliant per Microchip product page. Industrial -40°C to +85°C operating range; not AEC-Q100 qualified (choose ATSAML21E15B-A variants for automotive). Functional Safety variants available for IEC 60730 Class B compliance in white goods.
