ATSAMD21E15B-AFT - 48MHz Cortex-M0+ MCU, 32KB Flash | Microchip
MPN: ATSAMD21E15B-AFT β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $3.05 | $30.50 |
| 100 | $2.61 | $261.00 |
| 500 | $2.28 | $1,140.00 |
| 1,000 | $1.96 | $1,960.00 |
ATSAMD21E15B-AFT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (Flash), working memory (SRAM), and configurable peripherals such as timers, communication interfaces, and ADCs. The Cortex-M0+ is the most energy-efficient member of the ARM Cortex-M family, optimized for deterministic real-time performance and ultra-low static power. The SAM D21 series sits within Microchip's broader portfolio of 8-bit PIC and 32-bit SAM ARM Cortex microcontrollers, targeting general-purpose, low-power, and connectivity-oriented designs across consumer, industrial, and IoT markets.
Key features of the ATSAMD21E15B-AFT include six SERCOM serial communication modules configurable as UART, SPI, or I2C, a 14-channel 12-bit ADC with up to 350 ksamples/s, a 10-bit DAC, multiple 16-bit timer/counters, and an RTC, plus USB 2.0 Full-Speed device support. The FuSa variant adds hardware support for safety features such as dual-core self-test, watchdog, and CRC modules that simplify IEC 60730 Class B certification. Sleep current is in the microamp range and full-power operation is gated by an efficient on-chip voltage regulator.
Architecturally, the device combines an ARM Cortex-M0+ core with a single-cycle hardware multiplier, Microchip's proprietary event system for deterministic peripheral signalling without CPU wake-up, and the Peripheral Touch Controller for capacitive sensing. The integrated Full-Speed USB PHY removes the need for external transceivers, and the SERCOM modules can be remapped to multiple pin positions to ease PCB routing.
Typical applications include USB HID peripherals, home appliance control boards subject to IEC 60730 safety requirements, low-power wireless sensor nodes, capacitive touch user interfaces, and small industrial control modules. The wide 1.62-3.63 V supply range also makes the part suitable for 1S Li-ion battery-powered products.
When designing with the ATSAMD21E15B-AFT, ensure the VDDCORE pin is decoupled with a 1 uF ceramic capacitor and that VDDIO and VDDIN share a clean rail. The part's FuSa documentation package (DS60001673) provides the self-test library and safety manual needed to claim Class B compliance. Migration between ATSAMD20 and ATSAMD21 parts is generally straightforward, but USB-equipped applications must verify the SAMD21 variant has the integrated PHY enabled.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found in the standalone manufacturer datasheet.
Drop-in alternatives for ATSAMD21E15B-AFT 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 ATSAMD21E15B-AFT (same form factor and footprint) β differing in Package, SRAM, ADC, Operating Temperature, RoHS Status.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAMD21E15A-AFT
β Drop-Inπ Reference alternative (not in catalog)
ATSAMD21E16B-AFT
β Drop-Inπ Reference alternative (not in catalog)
ATSAMD21E17B-AFT
β Drop-Inπ Reference alternative (not in catalog)
ATSAMD21E15B-AU
β Drop-Inβ In Stock
$1.45 / Unit
View Datasheet βATSAMD21G15B-AFT
β Drop-Inπ Reference alternative (not in catalog)
STM32L011F4P6
β Drop-Inβ In Stock
$0.46 / Unit
View Datasheet βSTM32F031F4P6
β Drop-Inπ Reference alternative (not in catalog)
ATSAMD21E15B-AFT Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ |
| Core Bit Width | 32-bit |
| Maximum Clock Frequency | 48 MHz |
| Program Memory (Flash) | 32 KB (32K x 8) |
| Data Memory (SRAM) | 4 KB |
| Operating Voltage Range | 1.62 V to 3.63 V |
| I/O Pins | 26 (max) |
| Package | 32-pin TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| ADC | 12-bit, up to 14 channels |
| DAC | 10-bit, 1 channel |
| Timer/Counters | TC: 3 x 16-bit, TCC: 2 x 16-bit |
| Communication Interfaces | 6 x SERCOM (UART/SPI/I2C), USB 2.0 Full-Speed Device, I2S |
| Functional Safety | IEC 60730 Class B (FuSa variant) |
| Operating Temperature Range | -40 C to +125 C |
| RoHS Status | Compliant |
| MSL Level | MSL3 (per JEDEC J-STD-020) |
ATSAMD21E15B-AFT Pin Configuration
| Pin 1 | PA00 β General-purpose I/O / XIN32 |
| Pin 2 | PA01 β General-purpose I/O / XOUT32 |
| Pin 3 | PA02 β General-purpose I/O / AIN0 |
| Pin 4 | PA03 β General-purpose I/O / AIN1 / VREFA |
| Pin 5 | PA04 β General-purpose I/O / AIN2 |
| Pin 6 | PA05 β General-purpose I/O / AIN3 |
| Pin 7 | PA06 β General-purpose I/O / AIN4 |
| Pin 8 | PA07 β General-purpose I/O / AIN5 |
| Pin 9 | VDDIO β I/O supply voltage |
| Pin 10 | GND β Ground |
| Pin 11 | PA08 β General-purpose I/O |
| Pin 12 | PA09 β General-purpose I/O |
| Pin 13 | PA10 β General-purpose I/O |
| Pin 14 | PA11 β General-purpose I/O / DM USB |
| Pin 15 | PA12 β General-purpose I/O / DP USB |
| Pin 16 | PA13 β General-purpose I/O |
| Pin 17 | PA14 β General-purpose I/O |
| Pin 18 | PA15 β General-purpose I/O |
| Pin 19 | PA16 β General-purpose I/O |
| Pin 20 | PA17 β General-purpose I/O |
| Pin 21 | PA18 β General-purpose I/O |
| Pin 22 | PA19 β General-purpose I/O |
| Pin 23 | PA20 β General-purpose I/O |
| Pin 24 | PA21 β General-purpose I/O |
| Pin 25 | PA22 β General-purpose I/O |
| Pin 26 | PA23 β General-purpose I/O |
| Pin 27 | PA24 β General-purpose I/O / USB_VBUS |
| Pin 28 | PA25 β General-purpose I/O |
| Pin 29 | VDDIN β Main supply voltage |
| Pin 30 | VDDCORE β Internal core voltage (decouple with 1uF) |
| Pin 31 | RESET β Reset input (active low) |
| Pin 32 | SWDIO β Serial Wire Debug I/O |
Typical Applications
ATSAMD21E15B-AFT is suitable for 7 applications: USB HID Peripherals, Home Appliance Control (IEC 60730 Class B), Battery-Powered IoT Sensor Nodes, Capacitive Touch User Interfaces, Low-Cost Industrial Sensor Modules, LED Lighting Control, Wearable Health Devices.
USB HID Peripherals
The ATSAMD21E15B-AFT integrates a USB 2.0 Full-Speed device PHY, removing the need for an external transceiver chip. Designers implement HID-class devices (keyboards, mice, custom input) using the on-chip 48 MHz PLL derived from the 8 MHz internal oscillator. The 32 KB Flash holds USB stack plus application code comfortably, and the 4 KB SRAM handles HID report buffers. Compared to a discrete USB-to-UART IC plus external MCU, this single-chip solution cuts BOM cost and PCB area.
Recommended
Home Appliance Control (IEC 60730 Class B)
The FuSa variant of the ATSAMD21E15B-AFT includes Microchip's IEC 60730 Class B safety library (AN2668) covering CPU register, SRAM, Flash, clock, and ADC self-test routines. White-goods designers integrate these routines to claim Class B certification for washing machines, dishwashers, and induction cooktops. The 32-TQFP footprint provides enough GPIO for triac-fired relay control, while the 12-bit ADC reads temperature sensors directly. The hardware watchdog and CRC peripheral are independently certified for safety use.
Recommended
Battery-Powered IoT Sensor Nodes
The ATSAMD21E15B-AFT's 1.62 V minimum supply and sub-microamp sleep current make it suitable for 1S Li-ion or 2x AA battery-powered IoT sensor nodes. The Cortex-M0+ core wakes from sleep in single-digit microseconds and runs the event system to monitor peripherals without CPU wakeup, achieving multi-year battery life on periodic sensor reads. The 12-bit ADC and six SERCOMs connect to I2C sensors, SPI radios, and UART GPS modules. The 32-TQFP is small enough for coin-cell sensor tiles.
Recommended
Capacitive Touch User Interfaces
The Peripheral Touch Controller (PTC) integrated in the ATSAMD21E15B-AFT supports up to 12 self-capacitance or mutual-capacitance touch channels without an external touch IC. Designers implement keypads, sliders, and wheels on home-appliance front panels using the SAME54's PTC library ported to SAMD21. The 32 KB Flash holds the touch library plus application logic. IEC 60730 Class B safety library applies to touch-sensing wet-environment designs.
Recommended
Low-Cost Industrial Sensor Modules
The ATSAMD21E15B-AFT's 32 KB Flash, 4 KB SRAM, and 48 MHz Cortex-M0+ core support Modbus RTU slave modules, 4-20 mA loop-powered sensor transmitters, and RS-485 field nodes. Six SERCOM blocks handle UART/RS-485, I2C sensor reads, and SPI ADC sampling simultaneously. The 1.62-3.63 V supply range allows direct connection to 3.3 V industrial rails. The wide -40 C to +125 C operating range suits outdoor and factory-floor deployments.
Recommended
LED Lighting Control
The ATSAMD21E15B-AFT can drive WS2812B / SK6812 addressable LED strips via SERCOM SPI with DMA, or PWM-dim analog LED strings using its 16-bit TCC timer/counter channels. The 12-bit DAC outputs 0-3.3 V control signals for tunable-white and color-mixing fixtures. Six SERCOMs manage DMX512 input, I2C ambient-light sensors, and UART debug ports concurrently. The 32 KB Flash fits commercial-grade color-management and wireless-debug firmware stacks.
Recommended
Wearable Health Devices
The ATSAMD21E15B-AFT's low active power (typically 7 mA at 48 MHz) and sub-microamp sleep current suit battery-powered wearables such as fitness bands and pulse-oximeter patches. Designers pair the on-chip 12-bit ADC to PPG photodiode front-ends and use the 10-bit DAC for haptic-driver control. Six SERCOMs interface to BLE modules, I2C accelerometers, and SPI displays. IEC 60730 Class B documentation is useful for medical-device regulatory submissions.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21E15B-AFT β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21E15A-AFT | ATSAMD21E16B-AFT | ATSAMD21E17B-AFT | ATSAMD21E15B-AU | STM32L011F4P6 |
|---|---|---|---|---|---|---|
| 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 |
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | STMicroelectronics - cross-brand | |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | |
| Max Clock Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 32 MHz | |
| Flash | 32 KB | 32 KB | 64 KB | 128 KB | 32 KB | |
| SRAM | 4 KB | 4 KB | 8 KB | 16 KB | 4 KB | |
| USB | USB 2.0 Full-Speed Device | USB 2.0 Full-Speed Device | USB 2.0 Full-Speed Device | No USB | ||
| Operating Temperature | -40 C to +125 C | -40 C to +85 C | -40 C to +125 C | -40 C to +85 C | ||
| Functional Safety | IEC 60730 Class B (FuSa) | No | IEC 60730 Class B | No |
Key Differentiators
- Integrated USB 2.0 Full-Speed PHY (vs STM32L011F4P6)
- IEC 60730 Class B Functional Safety (vs ATSAMD21E15A-AFT)
- 128 KB Flash scalability in same footprint (vs ATSAMD21E17B-AFT)
Design Notes
Estimated power budget at 48 MHz active mode is approximately 7 mA per the SAM D21 datasheet (DS40001882D). At 1.8 V supply with 32 KB Flash executing from cache and all SERCOMs disabled, current is around 2.5 mA. Sleep mode (STANDBY) drops to 1.4 uA with full SRAM retention and RTC running. For coin-cell designs, gate the MCU's VDDIN with a load switch to achieve 0.1 uA shelf-life current.
Place the VDDCORE decoupling capacitor (1 uF X7R 0402 or 0603) within 2 mm of the VDDCORE pin. The VDDIO and VDDIN pins can share a single rail but each must have its own 100 nF + 1 uF bulk decoupling pair within 5 mm. The 32-TQFP has an exposed pad that should be soldered to a ground plane for thermal dissipation - the part dissipates ~150 mW at full active load. Keep the 32.768 kHz crystal traces short and symmetric.
The USB DP/DM traces from PA11/PA12 to the USB connector should be routed as a 90-ohm differential pair with no stubs and length-matched within 150 mil. Place the 22 ohm series termination resistors within 4 mm of the device pins if the trace length exceeds 25 mm. Use the on-chip USB PHY only with a 48 MHz clock source derived from the PLL, never from the internal 8 MHz RC oscillator, to meet USB jitter spec.
Do not connect the SWDIO/SWDCLK pins to anything during operation - they are bidirectional debug pins and a stray load will prevent programming. The RESET pin requires a 10 kohm pull-up to VDDIN and a 1 nF capacitor to ground for noise immunity. Do not exceed 3.63 V on VDDIO/VDDIN - the part has no overvoltage protection. When migrating from SAMD20 to SAMD21, verify the SERCOM pin mapping has not changed in your firmware before bringing up USB.
Compliance Information
RoHS and REACH compliant per Microchip product declaration. Not AEC-Q100 qualified (automotive qualification) - not applicable for this general-purpose MCU. Halogen-free per Microchip green-product policy. Conflict-minerals compliant per Microchip CMRT filings.
