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Microchip Technology ATSAMR21G18A-MF
- Part No.:
- ATSAMR21G18A-MF
- Manufacturer:
- Microchip Technology
- Category:
- RF Transceiver ICs
- Package:
- 48-VFQFN Exposed Pad
- Datasheet:
-
ATSAMR21G18A-MF.pdf
- Description:
- IC RF TXRX+MCU ISM<1GHZ 48QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,393
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Product details
Overview
ATSAMR21G18A-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 48-pin QFN package. It operates at up to 48MHz, supports SleepWalking peripherals, and delivers -99dBm RX sensitivity with +4dBm TX output for IEEE 802.15.4-compliant mesh networking in battery-powered IoT sensor nodes.
For engineers reviewing the ATSAMR21G18A-MF datasheet, ATSAMR21G18A-MF pinout, ATSAMR21G18A-MF application, or ATSAMR21G18A-MF equivalent, key selection criteria include its integrated AT86RF233 transceiver co-processor, SERCOM-configurable USART/I²C/SPI interfaces, 8-channel 12-bit ADC with oversampling, hardware AES encryption, and RF pin layout (RFP/RFN differential pair) requiring strict 100Ω impedance control.
Technical Context
The ATSAMR21G18A-MF implements a dual-domain clock architecture with DFLL48M and FDPLL96M oscillators, enabling independent peripheral clock scaling to minimize power while maintaining CPU performance. Its Event System provides 12 asynchronous channels for inter-peripheral signaling without CPU intervention-even in standby mode-enabling autonomous sensor wake-up and data preprocessing.
Transceiver operation relies on dedicated SERCOM4 hardware interfacing to the integrated AT86RF233, supporting O-QPSK modulation, hardware MAC (auto-ack/retry), 128-byte frame buffer, and antenna diversity control via FECTRL[0..5] pins. The RF front-end uses differential RFP/RFN pins with 0.9V common-mode voltage in TX and 20mV drop in RX, mandating AC-coupled PCB layout with <30pF pin-to-ground capacitance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| CPU Core | ARM Cortex-M0+ @ 48MHz; single-cycle multiplier and Micro Trace Buffer for real-time code profiling. |
| Memory | 256KB Flash (in-system programmable), 32KB SRAM; supports boot loader updates via SWD or any SERCOM interface. |
| Wireless Transceiver | Integrated AT86RF233: 250kb/s IEEE 802.15.4 PHY, -99dBm sensitivity, +4dBm output, hardware AES-128, SFD detection, CRC-16. |
| Analog Peripherals | 8-channel 12-bit ADC @ 350ksps with 1x–16x programmable gain, oversampling to 16-bit resolution, and two window comparators. |
| Timing & Control | Three 16-bit TCs (cascadable to 32-bit) + three 16-bit TCCs with complementary PWM, dead-time insertion, and dithering for motor/lighting control. |
| Connectivity | One full-speed USB 2.0 device/host interface (12Mbps, 8 endpoints); five SERCOMs configurable as USART/I²C/SPI/LIN. |
| Power Management | Idle and standby sleep modes; SleepWalking enables peripherals to execute tasks (e.g., ADC sampling, event triggering) without waking CPU. |
Pinout & Package
ATSAMR21G18A-MF is housed in a 48-pin QFN package (7mm × 7mm, 0.5mm pitch) with an exposed thermal pad internally connected to GND. The package requires soldering the center pad to PCB ground for mechanical stability and thermal dissipation-this pad is not a functional signal replacement for GND pins.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RFP / RFN (Pins 17/18) | Differential RF transceiver interface | 100Ω differential port for 2.4GHz TX/RX; mandates AC coupling and <30pF pin-to-ground capacitance to maintain common-mode feedback stability. |
| XTAL1 / XTAL2 (Pins 3/4) | 16MHz crystal oscillator inputs for RF transceiver | Direct connection to AT86RF233 XOSCRF; DC level fixed at 0.9V; parasitic capacitance ≤3pF required for crystal load accuracy. |
| PA30 / PA31 (Pins 45/46) | SWD debug interface | Two-pin Serial Wire Debug (SWCLK/SWDIO); supports non-intrusive on-chip debugging and flash programming without halting CPU execution. |
| PA12–PA15 (Pins 21–24) | FECTRL[2..5] and SERCOM2 signals | Configurable as antenna diversity control outputs (DIG1–DIG4) or SERCOM2 peripheral functions; critical for external RF switch management. |
| GNDANA / AVDD / DVDD (Pins 5/6/7, 29) | Analog/digital power domains | Separate analog (1.8V) and digital (1.8V) supplies with dedicated ground planes; bypass capacitors mandatory per datasheet layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Hardware-assisted IEEE 802.15.4 MAC | Auto-acknowledge, auto-retry, and frame buffering reduce host CPU overhead and improve packet reliability in lossy environments. |
| SleepWalking peripheral autonomy | ADC, RTC, or event-triggered peripherals execute predefined tasks (e.g., periodic sampling, threshold detection) in standby mode without CPU wake-up. |
| Peripheral Touch Controller (PTC) | Supports up to 48 capacitive touch channels (8×6 matrix) for slider/wheel/proximity sensing with noise immunity in noisy industrial settings. |
| Configurable SERCOM interfaces | Five SERCOM modules each support USART/I²C/SPI/LIN-enabling mixed-protocol communication (e.g., I²C sensors + SPI displays) on shared pins. |
| Hardware AES-128 engine | Dedicated cryptographic accelerator operates in parallel with PHY transactions, enabling secure over-the-air firmware updates without compromising real-time RF timing. |
Applications
| Smart Utility Metering | Industrial Wireless Sensor Node |
|---|---|
Use Scenario: Battery-powered gas/water meters transmitting consumption data hourly via Zigbee/Thread mesh networks. IC Role / Device Role / Timing Role: Primary system-on-chip handling sensor acquisition (pressure/flow), secure data encryption, and low-duty-cycle 2.4GHz RF transmission. Use Value: Integrated AT86RF233 eliminates external transceiver BOM cost; SleepWalking enables precise RTC-triggered wake-up and transmission, extending 10-year battery life. | Use Scenario: Vibration/temperature monitoring on rotating machinery with edge analytics before cloud upload. IC Role / Device Role / Timing Role: Real-time data acquisition hub using 8-channel ADC and TCC-driven PWM for local actuator control during fault events. Use Value: Hardware CRC-32 and AES ensure data integrity/authenticity; differential RFP/RFN layout minimizes EMI coupling from motor drives. |
| Home Automation Gateway | Asset Tracking Beacon |
Use Scenario: Hub aggregating BLE/Zigbee devices and bridging to Wi-Fi/Ethernet via USB-hosted protocol stack. IC Role / Device Role / Timing Role: Dual-role USB controller acts as embedded host for dongles and device for PC configuration; SERCOMs manage multiple radio stacks. Use Value: Five SERCOMs allow concurrent I²C (sensor hub), SPI (flash storage), and UART (debug console) without resource contention. | Use Scenario: GPS-denied indoor logistics tag reporting location via RSSI triangulation across fixed gateways. IC Role / Device Role / Timing Role: Ultra-low-power beacon broadcasting encrypted ID packets every 5 seconds using hardware MAC timing. Use Value: -99dBm RX sensitivity enables reliable reception at 100m range; 2.4GHz ISM band avoids licensed spectrum fees and regulatory delays. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar wireless microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ATSAMR21E18A-MF | 32-pin QFN, 28 GPIOs (vs. 48-pin/28 GPIO), no XOSC32K, reduced SERCOM count (4 vs. 5), same core/peripherals. | Compact footprint for space-constrained designs; lacks dedicated 32.768kHz crystal support for high-accuracy RTC calendar. | Select when board area is critical and 32-pin layout suffices; verify SERCOM allocation for multi-interface requirements. |
| STM32WB55RGV | ARM Cortex-M4/M0+ dual-core, Bluetooth 5.0 + IEEE 802.15.4, 1MB Flash, 256KB RAM, different RF architecture (integrated BLE stack). | Bluetooth LE gateway functionality; higher memory for complex protocol stacks; no native Zigbee support without external coordinator. | Choose for Bluetooth-centric applications or when dual-core processing (M4 for app, M0+ for radio) is required; re-evaluate RF certification path. |
Compared with ATSAMR21E18A-MF, ATSAMR21G18A-MF offers expanded I/O and SERCOM resources for multi-sensor systems, while STM32WB55RGV provides Bluetooth integration at the cost of divergent software ecosystem and RF stack licensing.
Availability
ATSAMR21G18A-MF is available at Aetrix Electronics and suitable for smart metering, industrial wireless sensor networks, home automation gateways, and asset tracking beacons requiring stable component supply across extended product lifecycles.
Supply support for ATSAMR21G18A-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 acquired Atmel in 2016 and maintains the SMART ARM-based microcontroller portfolio, emphasizing low-power, integrated wireless solutions for industrial and IoT markets.
The SAM R21 product line was designed specifically for battery-operated IEEE 802.15.4 applications-combining ARM Cortex-M0+ efficiency with AT86RF233 RF performance and SleepWalking autonomy to minimize active time and extend operational life.
FAQ
What is the maximum data rate supported by the ATSAMR21G18A-MF transceiver?
The ATSAMR21G18A-MF integrates the AT86RF233 transceiver, which supports IEEE 802.15.4-compliant data rates of 250kb/s (standard), 500kb/s, 1000kb/s, and 2000kb/s. However, only the 250kb/s rate is guaranteed across the full -40°C to +125°C operating range; higher rates are specified only for -40°C to +85°C per the datasheet. ATSAMR21G18A-MF firmware must configure the transceiver's modulation and spreading parameters accordingly.
Does ATSAMR21G18A-MF support external serial flash memory?
Yes, ATSAMR21G18A-MF supports optional external serial flash memory via SPI interface, with reference design compatibility for Macronix MX25V4006EWSK (4Mb). The device's SERCOM modules can be configured as SPI master to manage external flash for firmware storage or data logging, though the onboard 256KB Flash remains primary program memory. ATSAMR21G18A-MF does not integrate serial flash internally.
How is the RF section powered and isolated on ATSAMR21G18A-MF?
ATSAMR21G18A-MF uses dedicated analog (AVDD/AVSS) and digital (DVDD/DVSS) power domains for the AT86RF233 transceiver, with internal LDOs generating regulated 1.8V supplies. These domains must be separated on PCB with individual bypass capacitors (100nF) and split ground planes to prevent digital switching noise from degrading RF sensitivity. The RFP/RFN differential pair requires strict 100Ω controlled impedance routing.
Can ATSAMR21G18A-MF operate without an external 16MHz crystal?
No-ATSAMR21G18A-MF requires an external 16MHz crystal connected to XTAL1/XTAL2 pins to drive the AT86RF233 transceiver's RF synthesizer. While the MCU core can use internal oscillators (DFLL48M, OSC8M), the RF section mandates this crystal for frequency accuracy and spectral purity. Omitting it prevents transceiver initialization and results in RF failure. ATSAMR21G18A-MF's XOSCRF circuit is hardwired to these pins with no alternative clock source.
What debug interfaces are available on ATSAMR21G18A-MF?
ATSAMR21G18A-MF provides a two-pin Serial Wire Debug (SWD) interface using PA30 (SWCLK) and PA31 (SWDIO) pins, supporting non-intrusive on-chip debugging, flash programming, and real-time trace via Micro Trace Buffer. It does not support JTAG. Debug tools must comply with ARM SWD protocol; no additional UART or USB-based debug is built-in-USB is strictly for application-level host/device communication.
ATSAMR21G18A-MF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- SMART™ SAM R21
- Package/Case:
- 48-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:
- 28
- 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:
- 48-QFN (7x7)
ATSAMR21G18A-MF FAQ
1.How can I place an order for ATSAMR21G18A-MF through Aetrix?
Please submit a Request for Quotation (RFQ) for ATSAMR21G18A-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 ATSAMR21G18A-MF reliable?
The price and inventory of ATSAMR21G18A-MF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ATSAMR21G18A-MF is usually 5 days.
3.What payment methods are accepted for ATSAMR21G18A-MF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ATSAMR21G18A-MF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ATSAMR21G18A-MF?
ATSAMR21G18A-MF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ATSAMR21G18A-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 ATSAMR21G18A-MF?
For technical support, including ATSAMR21G18A-MF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ATSAMR21G18A-MF requirements.
6.How does Aetrix verify that ATSAMR21G18A-MF is sourced from the original manufacturer or authorized distributors?
All ATSAMR21G18A-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 ATSAMR21G18A-MF meets industry standards.
7.What is the process for return or replacement of ATSAMR21G18A-MF?
All ATSAMR21G18A-MF units undergo pre-shipment inspection (PSI). If there is an issue with ATSAMR21G18A-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 ATSAMR21G18A-MF part is unused and in its original packaging.
Return procedure for ATSAMR21G18A-MF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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