ATSAMD21E16B-AF - 48MHz Cortex-M0+ MCU 64KB | Microchip
MPN: ATSAMD21E16B-AF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $3.07 | $30.70 |
| 100 | $2.74 | $274.00 |
| 500 | $2.46 | $1,230.00 |
| 1,000 | $2.19 | $2,190.00 |
ATSAMD21E16B-AF Overview
The SAM D21 family is part of the Atmel SMART portfolio of 32-bit ARM Cortex-M0+ microcontrollers, ranging from 32 to 64 pins with up to 256KB Flash and 32KB SRAM, designed for simple migration across pin counts with identical peripheral modules, hex-compatible code, and identical linear address maps. As a Cortex-M0+ based MCU it offers a streamlined single-cycle ALU and provides a hardware single-cycle multiplier for fast integer arithmetic. The family targets low-power general-purpose applications while retaining a rich analog and digital peripheral mix, making it suitable for consumer, industrial, and battery-powered IoT endpoints.
Key features of the ATSAMD21E16B-AF include six SERCOM modules supporting UART, SPI with FIFOs, and I2C up to Fast-Mode Plus, a Full-Speed USB 2.0 device/host with on-chip transceiver and 8 endpoints, a 12-bit 350ksps ADC with up to 20 channels including hardware oversampling, two analog comparators with window mode, a 10-bit 350ksps DAC, and six 16-bit timer/counters for PWM, input capture, and frequency measurement. The integration of these peripherals reduces BOM cost in sensor hubs, human-interface devices, and motor-control signal-stage applications.
Architecture-wise, the ATSAMD21E16B-AF uses a two-level AHB/APB bus matrix with separate bridges for high-bandwidth peripherals such as USB, and a low-power peripheral bus for always-on functions. The Power Manager (PM) supports RUN, IDLE, STANDBY, BACKUP, and OFF sleep modes with typical RUN current of approximately 3 mA at 48 MHz with all peripherals enabled. The brown-out detector, supply-voltage monitoring, and on-chip voltage regulator enable reliable operation across 1.62 V to 3.63 V supply, with the AF suffix denoting 125°C industrial temperature grade and Pb-free TQFP-32 packaging.
Typical applications for the ATSAMD21E16B-AF include low-power IoT sensor nodes, USB HID peripherals, wearable fitness devices, smart-home control panels, industrial sensor hubs, and consumer audio accessories that need hardware PWM, USB, and capacitive touch support. Its low-power SleepWalking and Event System make it especially useful in event-driven designs where the CPU stays asleep while peripherals wake on a threshold crossing.
When designing with this MCU, ensure decoupling is generous - 0.1 µF X7R close to each VDD pin and a 4.7 µF bulk capacitor on VDDCORE is the recommended starting point. Designers must also configure the GCLK and DFLL blocks correctly before enabling SERCOM and USB to avoid lockups. The 32-pin TQFP-32 footprint allows hand-rework-friendly prototyping and is suitable for reflow profiles up to peak 260°C per JEDEC J-STD-020.
Drop-in alternatives for ATSAMD21E16B-AF — 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 ATSAMD21E16B-AF (same form factor and footprint) — differing in ADC, RoHS Status, DAC, SRAM, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21E16B-MFT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD21E18A-AU
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD21E15B-AFT
✅ Drop-In✓ In Stock
$1.96 / Unit
View Datasheet →ATSAMD21E15B-AU
✅ Drop-In✓ In Stock
$1.45 / Unit
View Datasheet →ATSAMD21E16B-AF Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M0+ |
| Core Size | 32-Bit, Single-Core |
| Maximum CPU Frequency | 48 MHz |
| Program Flash Memory | 64 KB (64K x 8) |
| SRAM | 8 KB |
| Operating Voltage Range | 1.62 V to 3.63 V |
| Package | 32-pin TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Temperature Grade (AF suffix) | Industrial, -40°C to +125°C |
| Connectivity | I²C, LINbus, SPI, UART/USART, USB |
| USB Module | USB 2.0 Full-Speed Host + Device, on-chip transceiver |
| Peripherals | Brown-out Detect/Reset, DMA, I²S, POR, PWM, WDT |
| Number of I/O Pins | 26 (typical for SAM D21E 32-pin) |
| ADC | 12-bit, up to 20 channels, 350 ksps |
| DAC | 10-bit, 350 ksps |
| Number of Timers | Six 16-bit TC, RTC, 24-bit SysTick |
| RoHS Status | Compliant (Pb-free) |
| MSL Level | MSL3 (per JEDEC J-STD-020) |
| Programming/Debug Interface | SWD (2-wire) |
| CoreMark/MHz | 2.46 |
ATSAMD21E16B-AF Pin Configuration
| Pin 1 | PA00 — EIC, EXTINT[0], SERCOM1[0], TCC2[0] |
| Pin 2 | PA01 — EIC, EXTINT[1], SERCOM1[1], TCC2[1] |
| Pin 3 | PA02 — EIC, EXTINT[2], SERCOM1_PAD2, AIN0, VOUT |
| Pin 4 | PA03 — EIC, EXTINT[3], SERCOM1_PAD3, AIN1, VREF |
| Pin 5 | PA04 — EIC, EXTINT[4], SERCOM0[0], TCC0[0], AIN4, AIN5 (REF/ADC input) |
| Pin 6 | PA05 — EIC, EXTINT[5], SERCOM0[1], TCC0[1], AIN5 |
| Pin 7 | PA06 — EIC, EXTINT[6], SERCOM0_PAD2, TCC1[0], AIN6, REF[0] |
| Pin 8 | PA07 — EIC, EXTINT[7], SERCOM0_PAD3, TCC1[1], AIN7, REF[1] |
| Pin 9 | VDD — Digital supply voltage (1.62V-3.63V) |
| Pin 10 | GND — Ground |
| Pin 11 | PA08 — EIC, SERCOM2[0], TCC0[0], TCC1[2], AIN16, I2S_SDI[0] |
| Pin 12 | PA09 — EIC, SERCOM2[1], TCC0[1], TCC1[3], AIN17, I2S_MCK[0] |
| Pin 13 | PA10 — EIC, SERCOM2[2], TCC1[0], I2S_SCK[0], GCLK_IO4 |
| Pin 14 | PA11 — EIC, SERCOM2[3], TCC1[1], I2S_FS[0], GCLK_IO5 |
| Pin 15 | PA12 — EIC, SERCOM4[0], TCC2[0], TCC0[2] |
| Pin 16 | PA13 — EIC, SERCOM4[1], TCC2[1], AIN19 |
| Pin 17 | PA14 — EIC, SERCOM4[2], TCC0[4], SWDCLK (debug) |
| Pin 18 | PA15 — EIC, SERCOM4[3], TCC0[5], SWDIO (debug) |
| Pin 19 | PA16 — EIC, SERCOM3[0], TCC2[2], TCC0[6] |
| Pin 20 | PA17 — EIC, SERCOM3[1], TCC2[3], TCC0[7] |
| Pin 21 | PA18 — EIC, SERCOM3[2], TC3[0], TCC1[2] |
| Pin 22 | PA19 — EIC, SERCOM3[3], TC3[1], TCC1[3] |
| Pin 23 | PA20 — EIC, SERCOM5[2], TC7[0], GCLK_IO6 |
| Pin 24 | PA21 — EIC, SERCOM5[3], TC7[1], GCLK_IO7 |
| Pin 25 | PA22 — EIC, SERCOM5[0], TC4[0], TCC0[4] |
| Pin 26 | PA23 — EIC, SERCOM5[1], TC4[1], TCC0[5], USB_ID |
| Pin 27 | PA24 — EIC, SERCOM5[2], TC5[0], USB_DM (negated) |
| Pin 28 | PA25 — EIC, SERCOM5[3], TC5[1], USB_DP |
| Pin 29 | PB02 — EIC, SERCOM5[0], TC6[0], ADC[0], SHDN |
| Pin 30 | PB03 — EIC, SERCOM5[1], TC6[1], SHDN_PWR |
| Pin 31 | GND — Ground |
| Pin 32 | VDD — Digital supply voltage (1.62V-3.63V) |
Typical Applications
ATSAMD21E16B-AF is suitable for 6 applications: Low-Power IoT Sensor Node, USB HID Peripheral (Mouse/Keyboard/Custom), Wearable Fitness Device, Smart-Home Control Panel, Industrial Sensor Hub, Consumer Audio Accessory.
Low-Power IoT Sensor Node
The ATSAMD21E16B-AF's Cortex-M0+ core at 48 MHz and 64 KB Flash make it well suited to event-driven IoT sensor nodes that communicate over BLE or LoRa peripherals. The device's IDLE, STANDBY, and BACKUP sleep modes keep quiescent draw low while the Event System wakes peripherals without CPU involvement. According to Microchip datasheet 40001882A, typical RUN consumption is around 3 mA at 48 MHz, dropping to microamp levels in BACKUP. This combination enables battery-powered designs with months of operating life when periodically waking to sample a sensor and transmit a short burst.
Recommended
USB HID Peripheral (Mouse/Keyboard/Custom)
With on-chip USB 2.0 Full-Speed host+device support, eight endpoints, and 2 KB FIFO, the ATSAMD21E16B-AF is a natural fit for USB HID peripherals such as keyboards, mice, game controllers, and custom HID devices. Unlike microcontrollers that need an external USB transceiver, the integrated transceiver plus internal 1.5 kΩ pull-up simplify PCB layout to a few decoupling caps and a USB connector. The 48 MHz DFLL locked to a 32.768 kHz reference keeps USB packet timing inside the required ±0.25% tolerance.
Recommended
Wearable Fitness Device
Wearable fitness bands require a mix of low-power operation, robust timers, and responsive sensing - exactly what the ATSAMD21E16B-AF provides. The Cortex-M0+ core at 48 MHz runs gesture and step-counting algorithms while the SERCOM peripherals handle I²C connections to accelerometers and optical heart-rate sensors. The 12-bit ADC with hardware oversampling supports pulse-oximetry front-ends, and the 10-bit DAC can drive haptic feedback. Operating from a 3.3 V LDO and CR2032 or small Li-Po battery, the device powers down peripherals individually via PMUX sleep modes.
Recommended
Smart-Home Control Panel
Smart-home control panels combine user interfaces, communications, and protocol conversion - roles the ATSAMD21E16B-AF handles efficiently. Its 64 KB Flash accommodates Wi-Fi/BLE state machines plus capacitive-touch libraries, while SERCOM peripherals bridge UART/SPI to child devices. The on-chip 12-bit ADC reads panel voltages or battery telemetry, and the integrated TC modules generate PWM for LED backlights or haptic drivers. Up to 26 GPIO remain free in TQFP-32 for switches, sensors, and indicator LEDs.
Recommended
Industrial Sensor Hub
An industrial sensor hub aggregates analog and digital sensor readings into a unified interface, which the ATSAMD21E16B-AF supports through 6 SERCOM + DMA + 12-bit ADC channels. Industrial temperature grade (-40 to +125°C) on the AF suffix makes it suitable for factory automation. The integrated timers, watchdog, and brown-out detector deliver robust operation in electrically noisy plants. The Event System triggers ADC sampling without CPU intervention, allowing deterministic sensor-fusion.
Recommended
Consumer Audio Accessory
Consumer audio accessories such as USB DAC dongles, MIDI controllers, and headsets benefit from the ATSAMD21E16B-AF's USB, I²S, and PWM timer channels. I²S drives external audio CODECs at 32-96 kHz sample rates, while four TC channels produce PWM audio or haptic feedback. The 64 KB Flash can host USB MIDI class drivers with minimal external components. Operating supply 1.62-3.63 V allows direct Li-Po battery use.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21E16B-AF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21E16B-MFT | ATSAMD21E18A-AU | ATSAMD21E15B-AFT |
|---|---|---|---|---|
| Package | TQFP-32 (7x7 mm) | TQFP-32 (7x7 mm) - same | TQFP-32 (7x7 mm) - same | TQFP-32 (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core | ARM Cortex-M0+ 32-bit | ARM Cortex-M0+ 32-bit | ARM Cortex-M0+ 32-bit | ARM Cortex-M0+ 32-bit |
| Flash / SRAM | 64 KB / 8 KB | 64 KB / 8 KB | 256 KB / 32 KB | 32 KB / 4 KB |
| Max CPU Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| 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 |
| USB Module | USB 2.0 FS Host+Device | USB 2.0 FS Host+Device | USB 2.0 FS Host+Device | USB 2.0 FS Host+Device |
| Temperature Grade (Suffix) | Industrial -40 to +125°C (AF) | Industrial -40 to +125°C (MF) | Industrial -40 to +85°C (AU) | Industrial -40 to +125°C (AF) |
| Approx. 1k-unit price | ~$2.19 | ~$2.19 (same) | ~$3.85 (larger Flash) | ~$1.95 (smaller Flash) |
Key Differentiators
- Full-speed USB on-chip with host+device and 8 endpoints - removes external transceiver and pull-up (vs ATSAMD21E15B-AFT)
- Industrial 125°C temperature grade on AF suffix (vs ATSAMD21E18A-AU)
- Larger Flash/SRAM footprint with same Cortex-M0+ 48 MHz and TQFP-32 pinout (vs ATSAMD21E15B-AFT)
- Pin-compatible upgrade path to ATSAMD21E18A-AU with same firmware (vs ATSAMD21E18A-AU)
Design Notes
Place a 0.1 µF X7R ceramic close to every VDD pin (pins 9 and 32 on TQFP-32) plus one 4.7 µF bulk on the regulator output; the on-chip LDO draws transient current when SERCOM modules start up. Estimated: peak inrush on cold boot can hit 80 mA for <2 ms, so choose the bulk cap with low ESR ceramic above 4.7 µF.
At full 48 MHz CPU load and 3.3 V supply, dissipation is approximately 3 mA × 3.3 V = 9.9 mW; the TQFP-32 θJA of about 56 °C/W raises junction temperature only ~0.6 °C above ambient. No heatsink is required. Industrial designs must still derate to the -40 to +125 °C operating range.
Configure the GCLK_MAIN source (OSCCTRL/DFLL48M) BEFORE enabling SERCOM and USB to avoid I²C/SPI lockups and USB packet loss. The AF suffix guarantees 125 °C, but failure to lock the DFLL against a 32.768 kHz crystal degrades USB timing beyond the ±0.25% spec. Always program the NVMCTRL with proper write/erase wait-state tables for the chosen system clock.
Route the USB DP/DM pair (PA24/PA25) as a 90-ohm differential with no stubs, and keep the series ferrite bead within 5 mm of the connector. Keep SWD (PA14/PA15) short and away from switching regulators. Decouple VDDCORE pin with a 1 µF ceramic; the entire MCU operates from this internal rail, so it must be quiet.
Trace impedance matching for the SERCOM ports is not critical for UART, but for I²C/SPI faster than 1 MHz, keep rise/fall time <10 ns by routing over a continuous reference plane. Place the 32.768 kHz crystal within 4 mm of XIN/XOUT with guardring to reduce EMI.
Compliance Information
RoHS, REACH, and Pb-free per Microchip datasheet 40001882A. Industrial -40 to +125°C operating range (-AF suffix). Not AEC-Q100 qualified (use ATSAMD21E16B-MFT for automotive-grade qualified alternatives). MSL3 per JEDEC J-STD-020.
