ATSAMD21J16B-MF - ARM Cortex-M0+ 48MHz 64KB Flash MCU | Microchip
MPN: ATSAMD21J16B-MF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.78 | $37.80 |
| 100 | $3.36 | $336.00 |
| 500 | $2.99 | $1,495.00 |
| 1,000 | $2.65 | $2,650.00 |
ATSAMD21J16B-MF Overview
What is a Cortex-M0+ microcontroller? A microcontroller (MCU) is a single-chip computer that integrates a CPU core, memory, and programmable peripherals. The ARM Cortex-M0+ is ARM's smallest and most energy-efficient 32-bit core, designed for ultra-low-power embedded applications while retaining the broader ARMv6-M Thumb instruction set and a deterministic interrupt model. The SAM D21 family sits within Microchip's broader hierarchy of ARM-based MCU -> 32-bit microcontroller -> embedded controller, and is widely used as a modern replacement for 8-bit AVR and legacy ARM7 designs.
Key features include 64KB Flash with ECC, 8KB SRAM, six SERCOM interfaces that can each operate as USART, SPI, or I2C, a 12-bit 350 ksps ADC with up to 20 channels, a 10-bit 350 ksps DAC, full-speed USB 2.0 with on-chip transceiver, and a 2.46 CoreMark/MHz performance figure. The device also integrates a 32 kHz RTC, multiple sleep modes down to sub-microamp current, and a 6-channel event system for inter-peripheral signaling.
Architecturally, the SAMD21J16B uses a single-cycle hardware multiplier, an MPU for memory protection, and Microchip's standard Atmel/Microchip peripheral set mapped through SERCOM multiplexing, allowing flexible pin function allocation. The 64-QFN (9x9 mm) package exposes 52 GPIO and supports operation across the industrial -40C to +125C temperature range.
Typical applications include USB human-interface devices, IoT sensor nodes, low-power wireless sensor hubs, wearable health monitors, industrial control panels, and consumer appliances. Its balance of low power, USB, and analog integration suits both battery-powered and mains-powered embedded systems.
When designing with this part, observe the recommended 0.1uF + 1uF + 10uF decoupling network near VDD and VDDIO, and follow the QFN thermal pad soldering guidelines for reliable ground continuity. Programming is supported through MPLAB X IDE, Atmel Studio 7, and the SAMD21 core within the Arduino IDE.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the standalone manufacturer datasheet. Information was cross-verified across DigiKey, Mouser, and Microchip product pages.
Drop-in alternatives for ATSAMD21J16B-MF — 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 ATSAMD21J16B-MF (same form factor and footprint) — differing in SRAM, Operating Temperature, USB, DAC, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD21J18A-MF
✅ Drop-In✓ In Stock
$3.6 / Unit
View Datasheet →ATSAMD21J15B-MFT
✅ Drop-In✓ In Stock
$2.39 / Unit
View Datasheet →ATSAMD21J17D-MF
✅ Drop-In✓ In Stock
$2.2 / Unit
View Datasheet →ATSAMD21E18A-MF
✅ Drop-In✓ In Stock
$6.95 / Unit
View Datasheet →ATSAMD21J16B-AF
✅ Drop-In✓ In Stock
$2.52 / Unit
View Datasheet →ATSAMD21J16B-MF Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ (32-bit) |
| Series | SAM D21J (FuSa Functional Safety) |
| Maximum CPU Frequency | 48 MHz |
| CoreMark/MHz | 2.46 |
| Program Memory (Flash) | 64 KB (64K x 8) |
| SRAM | 8 KB |
| Operating Voltage | 1.62 V to 3.63 V |
| Package | 64-pin QFN (9x9 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +125C |
| ADC | 12-bit, up to 20 channels, 350 ksps |
| DAC | 10-bit, 350 ksps |
| Communication Interfaces | 6x SERCOM (USART/SPI/I2C), USB 2.0 Full-Speed |
| GPIO | 52 (approximate, package-dependent) |
| RoHS Status | Compliant (Green) |
ATSAMD21J16B-MF 64-pin qfn (9x9 mm) Pin Configuration Guide
Pin configuration for ATSAMD21J16B-MF (64-pin qfn (9x9 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for ATSAMD21J16B-MF.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAMD21J16B-MF is suitable for 6 applications: USB Human Interface Device (HID), IoT Sensor Node / Edge Sensor, Wearable Health Monitor, Industrial Control Panel, Consumer Appliance UI Controller, Educational / Maker Platform.
USB Human Interface Device (HID)
The ATSAMD21J16B-MF suits USB HID peripherals such as keyboards, mice, gamepads, and custom input devices. Its integrated USB 2.0 Full-Speed controller with on-chip transceiver eliminates the external PHY, while the 64KB Flash holds HID report descriptors plus composite-device stacks. The Cortex-M0+ at 48 MHz easily handles polling rates above 1 kHz, and the 8KB SRAM supports multi-endpoint HID configurations. Compared to external PHY solutions, the integrated USB saves BOM cost and PCB area.
Recommended
IoT Sensor Node / Edge Sensor
For battery-powered IoT sensor nodes, the ATSAMD21J16B-MF delivers low active current, multiple SERCOM channels for SPI/IoT sensors, and a 12-bit ADC for direct transducer readout. Sleep modes down to a few microamps extend coin-cell life, while 64KB Flash accommodates TLS stacks and OTA bootloader overlays. The 64-QFN package fits inside compact sensor pods, and the industrial temperature range supports outdoor deployments. Designers can add a Sub-GHz or BLE radio via SERCOM without external logic.
Recommended
Wearable Health Monitor
The ATSAMD21J16B-MF fits wearable health devices such as heart-rate, SpO2, and motion trackers. Its small 64-QFN footprint, sub-microamp sleep modes, and 12-bit ADC enable battery-powered bio-sensing with minimal external components. The 48 MHz Cortex-M0+ executes DSP-style filtering on accelerometer data in real time, and the on-chip DAC drives LED drivers for photoplethysmography. Industrial -40C to +125C rating tolerates body-heat rise and outdoor use. A separate low-power companion MCU can wake the SAMD21 only when needed.
Recommended
Industrial Control Panel
The ATSAMD21J16B-MF serves industrial control panels where it drives keypads, indicator LEDs, character LCDs, and fieldbus interfaces. The 6 SERCOM ports multiplex into USART, SPI, or I2C for Modbus RTU, RS-485, and IO-Link sensors. The 12-bit ADC with 20 channels reads analog inputs for 4-20 mA loops. The -40C to +125C rating and QFN thermal pad suit factory-floor enclosures. The on-chip 32 kHz RTC timestamps events even in low-power modes.
Recommended
Consumer Appliance UI Controller
The ATSAMD21J16B-MF is well-suited to user-interface controllers in home appliances such as coffee machines, ovens, and washing machines. Its 48 MHz performance drives TFT or segment displays and capacitive touch sensing, while the 64KB Flash holds UI graphics and appliance state machines. The DAC can generate audio cues or bezel backlight PWM. The wide 1.62-3.63V supply tolerates noisy DC-DC rails typical in appliance power systems. Firmware can be updated via USB service-port mode.
Recommended
Educational / Maker Platform
The ATSAMD21J16B-MF is the silicon behind several popular maker boards, exposing the same peripherals students and hobbyists expect: USB, ADC, DAC, PWM, I2C/SPI, and I2S. The 64-QFN package is breadboard-friendly with carrier boards and supports the Arduino IDE via the Arduino Zero / MKR core. The 64KB Flash holds libraries for sensors, displays, and audio, while 8KB SRAM supports SD-card buffers and BLE throughput via SERCOM. The low BOM cost makes it a strong classroom pick.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD21J16B-MF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD21J18A-MF | ATSAMD21J15B-MF | ATSAMD21J17D-MF | ATSAMD21E18A-MF | ATSAMD21J16B-AF | PIC16F723A-I/ML |
|---|---|---|---|---|---|---|---|
| Package | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-TQFP - different footprint | 28-QFN (6x6) - different footprint |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | 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) | ARM Cortex-M0+ (32-bit) | ARM Cortex-M0+ (32-bit) | PIC16 (8-bit) |
| Maximum Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 20 MHz |
| Flash | 64 KB | 256 KB | 32 KB | 128 KB | 256 KB | 64 KB | 7 KB |
| SRAM | 8 KB | 32 KB | 8 KB | 16 KB | 32 KB | 8 KB | 384 B |
| USB | USB 2.0 FS device | USB 2.0 FS device | USB 2.0 FS device | USB 2.0 FS device | USB 2.0 FS device | USB 2.0 FS device | No USB |
| 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 | 1.62 V to 3.63 V | 1.62 V to 3.63 V | 1.8 V to 5.5 V |
Key Differentiators
- Lowest-cost 64KB Flash variant in the SAMD21J family (vs ATSAMD21J18A-MF)
- More Flash than the J15B without changing pinout (vs ATSAMD21J15B-MF)
- 32-bit ARM Cortex-M0+ versus 8-bit PIC16 (vs PIC16F723A-I/ML)
Design Notes
Decouple VDD and VDDIO with a 0.1uF X7R ceramic placed within 2 mm of each supply pin, plus a bulk 10uF near the regulator output. The SAM D21 datasheet recommends separating analog and digital supplies on the 64-QFN variant. Enable the on-chip brown-out detector (BOD33) at 1.85V to protect Flash integrity during supply droops in USB and battery applications.
The 64-QFN (9x9 mm) package exposes a central exposed pad (EP) that must be soldered to a contiguous ground plane for both electrical ground and thermal dissipation. The EP tie-down reduces junction-to-ambient thermal resistance by approximately 30 percent compared to a floating pad. Use a via array (0.3 mm drill, 0.6 mm pitch) under the EP to maintain ground continuity across PCB layers.
Route the USB DP and DM lines as a 90-ohm differential pair with maximum length under 50 mm and length matching within 0.5 mm. Keep the pair on the same layer with a continuous reference ground plane underneath. Place the 33-ohm series resistors within 4 mm of the MCU DP/DM pins to avoid reflections. Avoid routing near switching nodes or clock traces to maintain USB signal integrity.
Do not skip the 1uF VBUS decoupling capacitor on the USB supply pin - omission causes USB enumeration failures on some hosts. Always configure the NVMCTRL for double-word Flash programming when using the ASF or Microchip peripheral library. The SERCOM I2C pins require external pull-up resistors (typically 2.2 kohm to 10 kohm) per I2C specification; on-chip pull-ups are too weak for most bus speeds.
Compliance Information
Green/RoHS-compliant per Microchip product page. Not AEC-Q100 qualified - SAM D21 family is not specifically automotive-qualified.
