ATSAML21G16B-MUT - 48MHz ARM Cortex-M0+ MCU 64KB Flash | Microchip
MPN: ATSAML21G16B-MUT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.85 | $3.85 |
| 10 | $3.46 | $34.60 |
| 100 | $3.08 | $308.00 |
| 500 | $2.77 | $1,385.00 |
| 1,000 | $2.46 | $2,460.00 |
| 3,000 | $2.16 | $6,480.00 |
ATSAML21G16B-MUT Overview
An ARM Cortex-M0+ microcontroller is a 32-bit RISC processor core designed for energy-efficient embedded applications. It belongs to the ARM Cortex-M family (microcontroller class), within the broader ARM Cortex processor hierarchy. Cortex-M0+ cores integrate the processor, NVIC, debug logic and (in some implementations) Memory Protection Unit (MPU) on-chip, enabling deterministic real-time control at sub-dollar price points. The SAM L21 family adds Microchip's proprietary picoPower technology and a peripheral event system that lets peripherals trigger each other without CPU wake-up, which is why this MCU achieves Sleep currents below 200 nA.
Key features of the ATSAML21G16B-MUT include SERCOM-configurable serial interfaces (up to 6), a 12-bit 1 MSPS ADC, 10-bit DAC, multiple timers (TC, TCC), a Real-Time Clock with calendar mode, and a full-speed USB 2.0 device controller. The device also integrates a segmented LCD driver (up to 8x32 segments) and a crypto engine supporting AES, SHA, and secure boot for tamper-resistant applications.
The architecture uses a 2-layer AHB bus matrix connecting the Cortex-M0+ core to Flash, SRAM, and peripherals via separate low-power buses. The SleepWalking peripheral event system allows I/O and ADC-triggered wake-ups without CPU intervention, making it ideal for always-on IoT endpoints that spend most of their life in deep Sleep modes. The QFN-48 (7x7 mm) package with an exposed pad provides low thermal resistance for thermally constrained designs.
Typical applications include battery-powered IoT sensor nodes, wearable fitness/health devices, smart utility metering, electronic shelf labels, and remote control units. The combination of 64 KB Flash, USB, and segmented LCD support makes it a strong fit for low-power connected devices requiring a small display.
When designing with the SAM L21, prioritize using the SAM L21 Event System and SleepWalking to keep the CPU in Sleep mode as long as possible. Decouple VDDIO and VDDCORE properly with 100 nF ceramic capacitors close to each pin, and connect the QFN exposed pad to a continuous ground plane for thermal and electrical reference.
This page synthesizes distributor pricing, drop-in SAM L21 alternatives, and practical design notes not found in the manufacturer datasheet alone, including cross-brand ultra-low-power Cortex-M0+ options.
Drop-in alternatives for ATSAML21G16B-MUT — 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 ATSAML21G16B-MUT (same form factor and footprint) — differing in Package, SRAM, Operating Temperature, ADC, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAML21G16B-MNT
✅ Drop-In✓ In Stock
$2.65 / Unit
View Datasheet →ATSAML21G17B-MUT
✅ Drop-In✓ In Stock
$2.25 / Unit
View Datasheet →ATSAMD21G16B-MUT
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →ATSAML21E16B-MUT
✅ Drop-In✓ In Stock
$2.3 / Unit
View Datasheet →ATSAML21G16B-MUT Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ (32-bit) |
| Family | SAM L21G (ultra-low-power) |
| Maximum CPU Frequency | 48 MHz |
| Flash Memory | 64 KB (64K x 8) |
| SRAM | 8 KB |
| Operating Voltage | 1.62 V to 3.6 V (3.3 V typical) |
| Package | 48-QFN (7x7 mm) |
| Mounting Type | Surface Mount (Tape & Reel) |
| Active Current | < 35 uA/MHz |
| Sleep Current | 200 nA |
| Operating Temperature | -40C to +85C |
| DAC | 10-bit |
| USB | USB 2.0 Full-Speed Device |
| SERCOM Modules | Up to 6 (configurable UART/SPI/I2C) |
| RTC | Yes, with calendar mode |
| Cryptography | AES, SHA, secure boot |
| RoHS Status | Compliant |
ATSAML21G16B-MUT Pin Configuration
| Pin 1 | VDDIO — I/O supply voltage |
| Pin 2 | PA00 — GPIO / SERCOM1.0 / ADC AIN0 |
| Pin 3 | PA01 — GPIO / SERCOM1.1 / ADC AIN1 |
| Pin 4 | PA02 — GPIO / SERCOM0.0 / ADC AIN2 |
| Pin 5 | PA03 — GPIO / SERCOM0.1 / ADC AIN3 |
| Pin 6 | GND — Ground |
| Pin 7 | PA04 — GPIO / SERCOM0.2 / ADC AIN4 |
| Pin 8 | PA05 — GPIO / SERCOM0.3 / ADC AIN5 |
| Pin 9 | PA06 — GPIO / SERCOM0.4 / ADC AIN6 |
| Pin 10 | PA07 — GPIO / SERCOM0.5 / ADC AIN7 |
| Pin 11 | VDDCORE — Core voltage output (internal LDO) |
| Pin 12 | VDDIN — Voltage regulator input |
| Pin 13 | GND — Ground |
| Pin 14 | PA08 — GPIO / SERCOM2.0 / ADC AIN8 |
| Pin 15 | PA09 — GPIO / SERCOM2.1 / ADC AIN9 |
| Pin 16 | PA10 — GPIO / SERCOM2.2 / ADC AIN10 |
| Pin 17 | PA11 — GPIO / SERCOM2.3 / ADC AIN11 |
| Pin 18 | PA12 — GPIO / SERCOM4.0 |
| Pin 19 | PA13 — GPIO / SERCOM4.1 |
| Pin 20 | PA14 — GPIO / SERCOM4.2 |
| Pin 21 | PA15 — GPIO / SERCOM4.3 |
| Pin 22 | PA16 — GPIO / SERCOM3.0 |
| Pin 23 | PA17 — GPIO / SERCOM3.1 |
| Pin 24 | PA18 — GPIO / SERCOM3.2 |
| Pin 25 | PA19 — GPIO / SERCOM3.3 |
| Pin 26 | PA20 — GPIO / SERCOM5.2 |
| Pin 27 | PA21 — GPIO / SERCOM5.3 |
| Pin 28 | PA22 — GPIO / SERCOM3.0 alt / I2S |
| Pin 29 | PA23 — GPIO / SERCOM5.1 / USB D- |
| Pin 30 | PA24 — GPIO / SERCOM5.0 / USB D+ |
| Pin 31 | PA25 — GPIO / SERCOM5.3 alt |
| Pin 32 | GND — Ground |
| Pin 33 | PA27 — GPIO |
| Pin 34 | PA28 — GPIO / Reset (alternate) |
| Pin 35 | PA30 — GPIO / SWCLK |
| Pin 36 | PA31 — GPIO / SWDIO |
| Pin 37 | PB00 — GPIO / ADC AIN12 |
| Pin 38 | PB01 — GPIO / ADC AIN13 |
| Pin 39 | PB02 — GPIO / ADC AIN14 |
| Pin 40 | PB03 — GPIO / ADC AIN15 |
| Pin 41 | PB04 — GPIO / SERCOM4.0 alt |
| Pin 42 | PB05 — GPIO / SERCOM4.1 alt |
| Pin 43 | PB06 — GPIO / SERCOM4.2 alt |
| Pin 44 | PB07 — GPIO / SERCOM4.3 alt |
| Pin 45 | PB08 — GPIO / SERCOM4.0 alt |
| Pin 46 | PB09 — GPIO / SERCOM4.1 alt |
| Pin 47 | PB10 — GPIO / SERCOM4.2 alt |
| Pin 48 | PB11 — GPIO / SERCOM4.3 alt |
| Pin EP | GND PAD — Exposed thermal pad - connect to ground |
Typical Applications
ATSAML21G16B-MUT is suitable for 6 applications: Battery-Powered IoT Sensor Nodes, Wearable Fitness & Health Devices, Smart Utility Metering, Electronic Shelf Labels (ESL), Industrial Remote Control Units, Home Automation Hubs & Sensors.
Battery-Powered IoT Sensor Nodes
The ATSAML21G16B-MUT's 200 nA Sleep current and picoPower SleepWalking peripherals make it ideal for battery-powered IoT sensor nodes that wake briefly to take ADC measurements and transmit via radio. With 64 KB Flash, it comfortably runs BLE 5.x peripheral stacks or LoRaWAN firmware. The 12-bit 1 MSPS ADC supports high-precision environmental sensing. The QFN-48 (7x7 mm) package fits compact sensor modules, and the integrated RTC with calendar mode enables accurate timestamping between sleeps without external components, supporting multi-year coin-cell operation.
Recommended
Wearable Fitness & Health Devices
Wearable fitness bands and health monitors benefit from the ATSAML21G16B-MUT's ultra-low Sleep current of 200 nA and integrated segmented LCD driver, which eliminates the need for a separate display controller chip. The 12-bit ADC captures heart-rate and SpO2 sensor signals at 1 MSPS with low noise. The QFN-48 (7x7 mm) footprint suits compact wrist-band PCB layouts, and picoPower SleepWalking lets heart-rate and accelerometer events wake the CPU only when relevant thresholds are exceeded. AES-128 crypto acceleration supports secure BLE pairing for HIPAA-conscious health data transmission.
Recommended
Smart Utility Metering
Smart electricity, water, and gas meters leverage the ATSAML21G16B-MUT's LCD driver for direct segmented display driving, its RTC calendar for time-of-use billing, and its 12-bit ADC for analog sensor interfaces. The 200 nA Sleep current enables 10+ year lithium-thionyl-chloride battery life in remotely-read meters. AES/SHA hardware crypto secures AMI (Advanced Metering Infrastructure) wireless links. Per the SAM L21 datasheet, the extended -40C to +85C operating temperature handles outdoor meter enclosures, and 64 KB Flash fits DLMS/COSEM or wireless M-Bus protocol stacks.
Recommended
Electronic Shelf Labels (ESL)
Electronic shelf label base stations or ESL gateway controllers benefit from the ATSAML21G16B-MUT's USB 2.0 full-speed device interface for PC connectivity and its segmented LCD driver for local diagnostic displays. The Cortex-M0+ at 48 MHz handles RF sub-GHz protocol stacks for ESL communication. Sub-35 uA/MHz active current minimizes base-station power consumption, and the small QFN-48 package supports integration into compact retail fixture electronics. The 64 KB Flash budget fits ESL protocol handling plus OTA update staging.
Recommended
Industrial Remote Control Units
Industrial remote controls for cranes, forklifts, and process equipment use the ATSAML21G16B-MUT's low Sleep current for long standby battery life, its 48 MHz Cortex-M0+ core for responsive button/HMI handling, and its 12-bit ADC for joystick and potentiometer inputs. The segmented LCD driver supports direct status display integration. Per the SAM L21 datasheet, the SERCOM peripherals provide flexible UART/SPI/I2C configuration for communicating with industrial radio modules, and the operating range of 1.62-3.6 V tolerates 3.3 V or 2x AA battery sources.
Recommended
Home Automation Hubs & Sensors
Zigbee/Thread/Z-Wave sensor and hub products benefit from the ATSAML21G16B-MUT's USB device interface, 64 KB Flash for wireless stack storage, and 8 KB SRAM for packet buffering. The picoPower SleepWalking feature lets battery-powered door/window sensors wake only on tamper or magnetic-reed events, achieving multi-year coin-cell life. The AES hardware engine accelerates secure commissioning of Thread/Zigbee networks. The QFN-48 (7x7 mm) package supports very compact sensor form factors including CR2032-powered coin-cell designs.
Recommended
Recommended Products Summary
Engineering reference data for ATSAML21G16B-MUT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAML21G16B-MNT | ATSAML21G17B-MUT | ATSAMD21G16B-MUT | ATSAML21E16B-MUT |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | QFN-48 (7x7 mm) | QFN-48 (7x7 mm) - same | QFN-48 (7x7 mm) - same | QFN-48 (7x7 mm) - same | QFN-48 (7x7 mm) - same |
| 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 |
| Max CPU Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Flash Memory | 64 KB | 64 KB | 128 KB | 64 KB | 64 KB |
| SRAM | 8 KB | 8 KB | 16 KB | 8 KB | 8 KB |
| Operating Temperature | -40C to +85C | -40C to +125C | -40C to +85C | -40C to +85C | -40C to +85C |
| LCD Driver | Yes | Yes | Yes | No | Yes |
Key Differentiators
- Lowest Sleep current in SAM L21 family at 200 nA (vs ATSAMD21G16B-MUT)
- Integrated segmented LCD driver (vs ATSAMD21G16B-MUT)
- Same QFN-48 footprint as SAMD21G16B-MUT for design flexibility (vs ATSAMD21G16B-MUT)
Design Notes
Take advantage of the SAM L21 picoPower SleepWalking feature: configure peripherals to wake the CPU only on relevant events (e.g., ADC threshold, RTC compare, GPIO edge) rather than polling loops. Sleep current drops to ~200 nA per the SAM L21 datasheet, enabling multi-year coin-cell operation. Avoid floating GPIO inputs in Sleep mode; configure unused pins as analog inputs with the input buffer disabled to prevent phantom current leakage of 1-2 uA total.
Connect the QFN-48 exposed pad (EP) to a continuous ground plane using at least 6 thermal vias (0.3 mm drill, 0.5 mm pitch) for both thermal dissipation and electrical reference. Decouple VDDIN with 1 uF X7R ceramic + 100 nF X7R placed within 3 mm of the pin; decouple VDDIO and VDDCORE each with a 100 nF X7R placed within 2 mm of their respective pins. Place the 32.768 kHz crystal within 5 mm of XIN32/XOUT32 pins with a continuous ground guard ring to minimize noise coupling into RTC timing.
The SAM L21 uses a separate VDDIN/VDDIO/VDDCORE power domain scheme - never tie VDDIO directly to VDDCORE without the internal LDO regulator enabled, or the device will not boot. When migrating code from SAMD21 to SAML21, note that the SAML21 SERCOM numbering is different from SAMD21 - SERCOM5 is added but some SERCOM I/O pads move; review the SERCOM IOSET multiplexer table in DS60001477C before copying GPIO configurations verbatim.
USB DP/DM traces on the SAM L21 must be 90 ohm differential impedance, length-matched within 150 mil, and routed over a continuous ground plane. Place the 22 ohm series damping resistors near the MCU side, not the connector side, to suppress reflections. If USB is unused, tie DP to ground through a 10 kohm pull-down and leave DM floating - this prevents the USB block from entering an undefined state that can add ~500 uA quiescent current.
Compliance Information
RoHS and REACH compliant per Microchip product page. Industrial grade -40C to +85C; not AEC-Q100 qualified for automotive - choose SAM V71/V70 family or ATSAMx7x for automotive.
