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Microchip Technology ATSAMR21E18A-MF
- Part No.:
- ATSAMR21E18A-MF
- Manufacturer:
- Microchip Technology
- Category:
- RF Transceiver ICs
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
ATSAMR21E18A-MF.pdf
- Description:
- IC RF TXRX+MCU ISM>1GHZ 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:337
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Product details
Overview
ATSAMR21E18A-MF from Microchip Technology (formerly Atmel) is a 32-bit ARM Cortex-M0+ wireless microcontroller integrating an ultra-low-power 2.4GHz ISM band transceiver, 256KB Flash, 32KB SRAM, and USB 2.0 interface in a 32-pin QFN package. It operates at up to 48MHz, supports SleepWalking peripherals for autonomous low-power operation, and targets battery-powered IoT sensor nodes and mesh network endpoints requiring integrated RF and deterministic real-time control.
For engineers reviewing the ATSAMR21E18A-MF datasheet, ATSAMR21E18A-MF pinout, ATSAMR21E18A-MF application, or ATSAMR21E18A-MF equivalent, key selection criteria include its integrated AT86RF233-based 2.4GHz transceiver with -99dBm RX sensitivity and +4dBm TX output, 4-channel 12-bit ADC with oversampling up to 16-bit resolution, and hardware-accelerated AES-128 security engine - all within a -40°C to +125°C industrial temperature grade.
Technical Context
The ATSAMR21E18A-MF implements a tightly coupled ARM Cortex-M0+ core with Micro Trace Buffer (MTB) and single-cycle hardware multiplier, paired with a dedicated 2.4GHz transceiver subsystem based on the AT86RF233 PHY/MAC. Its clock system includes DFLL48M and FDPLL96M for precise frequency synthesis, enabling stable USB and RF timing without external crystals beyond the required 16MHz RF oscillator.
Peripherals are orchestrated via a 12-channel Event System supporting synchronous/asynchronous signaling even in standby mode, and SleepWalking enables peripherals like the RTC, ADC, or TCC to execute predefined tasks autonomously - waking the CPU only upon threshold crossing or result readiness. The device uses two independent power domains (AVDD/DVDD) and supports hardware-assisted MAC features including auto-acknowledge, auto-retry, and CRC-16 computation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| CPU Core | ARM Cortex-M0+ running at up to 48MHz; delivers 2.46 CoreMark/MHz for deterministic real-time execution. |
| Memory | 256KB Flash (in-system programmable), 32KB SRAM; supports boot loader updates via SWD or SERCOM interfaces. |
| Wireless Transceiver | Integrated 2.4GHz ISM band transceiver (AT86RF233-based); -99dBm RX sensitivity, +4dBm TX output, 250kb/s data rate. |
| Analog Peripherals | 4-channel 12-bit ADC (350ksps), programmable gain (1/2x–16x), oversampling to 16-bit resolution; two analog comparators with window mode. |
| Timing & Control | Three 16-bit Timer/Counters (TC) and three 16-bit Timer/Counters for Control (TCC); TCC supports complementary PWM, dead-time insertion, and dithering for motor/lighting control. |
| Security & Debug | Hardware AES-128 engine and True Random Generator; two-pin Serial Wire Debug (SWD) interface for non-intrusive on-chip debug. |
| Operating Range | 1.8V–3.6V supply voltage; -40°C to +125°C industrial temperature grade (Matte Sn plating). |
Pinout & Package
ATSAMR21E18A-MF is housed in a 32-pin QFN package (5mm × 5mm, 0.5mm pitch) with an exposed thermal pad internally connected to GND. The package requires soldering of the center pad to PCB ground for mechanical stability and thermal performance. Pin functions are multiplexed across PORT A (PA00–PA31) and PORT B (PB00–PB03), with dedicated RF pins (RFP/RFN), crystal inputs (XTAL1/XTAL2), and debug signals (SWCLK/SWDIO) assigned to fixed locations.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PA14 / PA15 | RFP / RFN | Differential 2.4GHz RF port (100Ω impedance); requires AC coupling and <30pF pin-to-ground capacitance for stable TX common-mode feedback. |
| PA00 / PA01 | XIN32 / XOUT32 | 32.768kHz crystal oscillator inputs - not present on SAM R21E; these pins default to GPIO or SERCOM functions. |
| PA30 / PA31 | SWCLK / SWDIO | Two-pin Serial Wire Debug interface; SWDIO auto-switches from GPIO on debugger detection. |
| PA06 / PA07 | AIN[6] / AIN[7] | Analog input channels for 12-bit ADC; support differential/single-ended acquisition and programmable gain stages. |
| PA24 / PA25 | USB_DM / USB_DP | Full-speed USB 2.0 differential pair (12Mbps); requires 27Ω series termination and proper ESD protection per USB spec. |
Key Features
| Feature | Design Value |
|---|---|
| SleepWalking Peripherals | Enables RTC, ADC, or TCC to operate autonomously in standby mode - waking CPU only on event completion or threshold breach, reducing average system power by >90% in sensor polling applications. |
| Hardware-Assisted MAC | Offloads frame handling: auto-acknowledge, auto-retry, SFD detection, CRC-16, and framing - eliminating software overhead and ensuring sub-10μs response latency for time-critical mesh protocols. |
| Peripheral Touch Controller (PTC) | Supports up to 48 capacitive touch sensing points (6×2 matrix on SAM R21E); integrates noise immunity algorithms and proximity detection without external components. |
| Event System | 12-channel inter-peripheral signaling fabric allowing direct hardware-triggered actions (e.g., ADC conversion start → DMA transfer → TCC update) without CPU intervention or ISR latency. |
| Integrated Security Engine | Dedicated AES-128 accelerator and True Random Number Generator enable secure over-the-air firmware updates and encrypted sensor data transmission with zero CPU cycle penalty. |
Applications
| Smart Utility Metering | Industrial Wireless Sensor Node |
|---|---|
Use Scenario: Battery-powered gas/water meter transmitting consumption data hourly via Zigbee-compatible 2.4GHz mesh network. IC Role / Device Role / Timing Role: Primary SoC executing metering firmware, managing RF link layer, and performing low-power wake-up scheduling using RTC alarms and SleepWalking ADC sampling. Use Value: Integrated AT86RF233 transceiver eliminates external RF IC BOM cost; -99dBm sensitivity ensures reliable 100m+ range through metal enclosures; 125°C rating supports outdoor deployment. | Use Scenario: Vibration and temperature monitoring node on rotating machinery in factory automation systems. IC Role / Device Role / Timing Role: Real-time signal acquisition host with synchronized ADC sampling, FFT preprocessing, and secure OTA firmware updates via USB or RF. Use Value: Hardware AES engine enables end-to-end encryption of sensor data; TCC dithering improves PWM resolution for active vibration damping control; 48MHz CPU handles edge analytics without external DSP. |
| Home Automation Gateway | Medical Wearable Endpoint |
Use Scenario: Sub-GHz/Zigbee bridge aggregating data from multiple sensors and relaying to cloud via Wi-Fi/Ethernet. IC Role / Device Role / Timing Role: Dual-role USB device/host controller enabling simultaneous firmware update (device) and debug trace capture (host) during field servicing. Use Value: SERCOM flexibility allows concurrent I²C (sensor hub), SPI (flash storage), and UART (debug console); 5 SERCOM instances eliminate need for external bus expanders. | Use Scenario: Disposable glucose monitor transmitting calibrated readings every 5 minutes to smartphone via BLE proxy. IC Role / Device Role / Timing Role: Ultra-low-power endpoint with SleepWalking ADC triggering on glucose reaction kinetics, then initiating secure RF burst transmission. Use Value: 1.8V minimum operating voltage extends coin-cell life; 125°C rating validates sterilization compatibility; hardware CRC-32 ensures data integrity over lossy links. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar wireless microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ATSAMR21G18A-MF | 48-pin QFN, 28 GPIOs, 5 SERCOMs (vs. 4), 8 ADC channels (vs. 4), includes XOSC32K for RTC calibration. | Required for designs needing >16 I/Os, higher-resolution RTC, or additional analog sensing channels. | Select when board layout accommodates larger footprint and application demands expanded peripheral count. |
| STM32WLE5JC | ARM Cortex-M4, LoRa/Sub-GHz transceiver (not 2.4GHz), 256KB Flash, 64KB SRAM, no integrated USB. | Targeted at long-range, low-data-rate LPWAN deployments rather than high-density 2.4GHz mesh networks. | Choose for sub-GHz regulatory compliance (e.g., EU 868MHz) or when LoRaWAN stack integration is mandatory. |
Compared with ATSAMR21G18A-MF, ATSAMR21E18A-MF reduces PCB area and BOM count via 32-pin packaging and optimized peripheral set, while maintaining identical RF performance and security features; versus STM32WLE5JC, it provides native 2.4GHz IEEE 802.15.4 compatibility and USB connectivity at the cost of LoRa physical layer support.
Availability
ATSAMR21E18A-MF is available at Aetrix Electronics and suitable for smart utility metering, industrial wireless sensor nodes, home automation gateways, and medical wearable endpoints requiring stable component supply across extended product lifecycles.
Supply support for ATSAMR21E18A-MF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Microchip Technology is a global semiconductor company specializing in microcontrollers, analog devices, and security solutions for industrial, automotive, and IoT markets.
The SAM R21 product line was designed specifically for ultra-low-power, RF-integrated embedded applications - combining ARM Cortex-M0+ processing, certified 2.4GHz transceivers, and hardware security engines in compact QFN packages.
FAQ
What is the maximum operating temperature specification for ATSAMR21E18A-MF?
ATSAMR21E18A-MF is rated for industrial operation from -40°C to +125°C, verified under continuous DC bias and functional testing per Microchip's qualification standards. This extended temperature range supports deployment in harsh environments such as outdoor utility meters, automotive under-hood sensors, and sterilizable medical devices - unlike the -40°C to +85°C variant (ATSAMR21E18A-MU).
Does ATSAMR21E18A-MF include an integrated 32.768kHz crystal oscillator for RTC accuracy?
No, ATSAMR21E18A-MF does not include the 32.768kHz crystal oscillator (XOSC32K). That feature is exclusive to the SAM R21G series. The ATSAMR21E18A-MF relies on its internal 32kHz ultra-low-power oscillator (OSCULP32K) or external 32.768kHz crystal connected to PA00/PA01 if higher RTC accuracy is required - though those pins default to GPIO/SERCOM functions and require configuration via SYSCTRL registers.
How many analog input channels does ATSAMR21E18A-MF support, and what is their resolution?
ATSAMR21E18A-MF supports four external analog input channels (AIN[0]–AIN[3]) routed to its 12-bit, 350ksps ADC. With hardware oversampling and decimation, it achieves effective resolutions of 13-, 14-, 15-, or 16-bit - confirmed in the datasheet's "ADC Oversampling and Decimation" section. Input ranges are configurable via programmable gain (1/2x to 16x) and support both differential and single-ended acquisition modes.
Can ATSAMR21E18A-MF operate without an external 16MHz crystal for the RF transceiver?
No, ATSAMR21E18A-MF requires an external 16MHz crystal connected to XTAL1/XTAL2 pins to drive the integrated AT86RF233 transceiver's RF oscillator (XOSCRF). The datasheet explicitly states this crystal is mandatory for RF functionality - internal oscillators cannot meet the phase noise and stability requirements of the 2.4GHz ISM band transceiver.
What debug interface does ATSAMR21E18A-MF provide, and how is it implemented?
ATSAMR21E18A-MF provides a two-pin Serial Wire Debug (SWD) interface using PA30 (SWCLK) and PA31 (SWDIO). SWDIO automatically switches from GPIO function to debug mode upon debugger detection (cold/hot plug), eliminating need for manual pin reconfiguration. This interface supports full non-intrusive on-chip debugging, flash programming, and real-time trace via the Micro Trace Buffer (MTB) - all documented in the DSU (Device Service Unit) chapter of the datasheet.
ATSAMR21E18A-MF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- SMART™ SAM R21
- Package/Case:
- 32-VFQFN Exposed Pad
- Packaging:
- Tray
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- TxRx + MCU
- RF Family/Standard:
- General ISM > 1GHz
- Protocol:
- -
- Modulation:
- O-QPSK
- Frequency:
- 2.4GHz
- Data Rate (Max):
- 250kbps
- Power - Output:
- 4dBm
- Sensitivity:
- -99dBm
- Memory Size:
- 256kB Flash, 32kB SRAM
- Serial Interfaces:
- I2C, SPI, UART, USART, USB
- GPIO:
- 16
- Voltage - Supply:
- 1.8V ~ 3.6V
- Current - Receiving:
- 11.3mA ~ 11.8mA
- Current - Transmitting:
- 7.2mA ~ 13.8mA
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 32-QFN (5x5)
ATSAMR21E18A-MF FAQ
1.How can I place an order for ATSAMR21E18A-MF through Aetrix?
Please submit a Request for Quotation (RFQ) for ATSAMR21E18A-MF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for ATSAMR21E18A-MF reliable?
The price and inventory of ATSAMR21E18A-MF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ATSAMR21E18A-MF is usually 5 days.
3.What payment methods are accepted for ATSAMR21E18A-MF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ATSAMR21E18A-MF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ATSAMR21E18A-MF?
ATSAMR21E18A-MF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ATSAMR21E18A-MF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for ATSAMR21E18A-MF?
For technical support, including ATSAMR21E18A-MF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ATSAMR21E18A-MF requirements.
6.How does Aetrix verify that ATSAMR21E18A-MF is sourced from the original manufacturer or authorized distributors?
All ATSAMR21E18A-MF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ATSAMR21E18A-MF meets industry standards.
7.What is the process for return or replacement of ATSAMR21E18A-MF?
All ATSAMR21E18A-MF units undergo pre-shipment inspection (PSI). If there is an issue with ATSAMR21E18A-MF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The ATSAMR21E18A-MF part is unused and in its original packaging.
Return procedure for ATSAMR21E18A-MF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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