ATSAML21J17B-UUT - 128KB Flash 48MHz ARM Cortex-M0+ MCU | Microchip
MPN: ATSAML21J17B-UUT β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.57 | $3.57 |
| 10 | $3.21 | $32.10 |
| 100 | $2.74 | $274.00 |
| 500 | $2.41 | $1,205.00 |
| 1,000 | $2.18 | $2,180.00 |
ATSAML21J17B-UUT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (Flash), working memory (SRAM), and a rich set of peripherals. The ARM Cortex-M0+ is the smallest and most energy-efficient core in the Cortex-M family, optimized for low-power deterministic embedded control. Within Microchip's portfolio, this device sits in the hierarchy: Cortex-M0+ core -> ARM 32-bit MCU -> SAM L21 ultra-low-power family -> Functional Safety (FuSa) product line -> embedded microcontroller. Its combination of Cortex-M0+ simplicity with SleepWalking, power domain gating, and ultra-low-power peripherals targets always-on, battery-powered applications.
Key features of the ATSAML21J17B-UUT include 128 KB Flash, 16 KB SRAM, an ARM Cortex-M0+ core at 48 MHz (2.46 CoreMark/MHz), full-speed USB device support, a 12-bit 1 Msps ADC, up to five SERCOM channels, a 32-bit RTC, and PTC (Peripheral Touch Controller) for capacitive touch sensing. The WLCSP64 package enables compact PCB designs, while the integrated power management supports SleepWalking, deep sleep, backup, and standby modes. Functional Safety (FuSa) features assist in safety-critical designs.
Architecturally, the SAM L21 family uses a sophisticated power-domain gating scheme that selectively powers only the peripherals in use. This, combined with the Cortex-M0+ two-stage pipeline and the Wake-on-event interrupt controller, minimizes wake-up latency while keeping idle current at 200 nA. The integrated 12-bit DAC, multiple timer/counter channels, and event system allow complex signal routing without CPU intervention.
Typical applications include wearable fitness and health devices, battery-powered IoT sensors, smart metering, home automation, remote controls, and ultra-low-power wireless sensor nodes. It is also used in industrial IoT edge nodes where long battery life and a small footprint (WLCSP64) are both essential.
When designing with this MCU, designers should pay attention to decoupling (place 100 nF X7R capacitors near each VDD pin), I/O bank voltage reference requirements for analog accuracy, and the need to configure unused pins as outputs with defined levels to minimize leakage. The WLCSP package also demands careful PCB pad design and assembly process control.
This page synthesizes distributor pricing, drop-in alternatives drawn from the same SAM L21 family, and practical design notes not found in the manufacturer datasheet, providing engineers a one-stop reference for sourcing the ATSAML21J17B-UUT.
Drop-in alternatives for ATSAML21J17B-UUT β 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 ATSAML21J17B-UUT (same form factor and footprint) β differing in ADC, Active Current, Functional Safety, Mounting Type, Operating Temperature.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAML21J18B-UUT
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$3.78 / Unit
View Datasheet βATSAML21J16B-UUT
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAML21E16B-UUT
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAMD21J17B-UUT
β Drop-Inπ Reference alternative (not in catalog)
ATSAML11E16A-UUT
β Drop-Inπ Reference alternative (not in catalog)
ATSAML21J17B-UUT Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ (32-bit, single-core) |
| Maximum Clock Frequency | 48 MHz |
| Flash Memory | 128 KB |
| SRAM | 16 KB |
| Supply Voltage (VDD) | 1.6 V to 3.6 V |
| Active Current | 35 uA/MHz (typical) |
| Sleep Current | 200 nA (typical) |
| Operating Temperature | -40C to +85C (industrial) |
| Package | 64-ball WLCSP (3.58 x 3.28 mm) |
| Mounting Type | Surface Mount |
| ADC | 12-bit, up to 1 Msps |
| USB | Full-Speed USB Device |
| Touch Controller | PTC (Peripheral Touch Controller) |
| Functional Safety | FuSa features supported |
| RoHS Status | Compliant (Green) |
ATSAML21J17B-UUT 64-ball wlcsp (3.58 x 3.28 mm) Pin Configuration Guide
Pin configuration for ATSAML21J17B-UUT (64-ball wlcsp (3.58 x 3.28 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 ATSAML21J17B-UUT.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAML21J17B-UUT is suitable for 6 applications: Wearable Fitness and Health Bands, Battery-Powered IoT Sensor Nodes, Smart Metering and Utility Endpoints, Home Automation Hubs and Edge Nodes, Remote Controls and Human-Machine Interfaces, Industrial IoT Sensor Edge Nodes.
Wearable Fitness and Health Bands
The ATSAML21J17B-UUT is engineered for wearable fitness bands where PCB area is severely constrained. Its 64-ball WLCSP measures only 3.58 x 3.28 mm, fitting comfortably beside a coin-cell battery and a small OLED. The 200 nA Sleep current and 35 uA/MHz active consumption, documented in the SAM L21 Family Data Sheet, allow multi-week battery life with continuous heart-rate monitoring. The integrated PTC supports reliable capacitive touch on the band housing, while full-speed USB enables convenient charging and firmware updates. This combination of tiny footprint, deep-sleep current, and a full Cortex-M0+ peripheral set is uniquely suited to the wearable segment.
Recommended
Battery-Powered IoT Sensor Nodes
IoT sensor nodes operating from a coin cell or two AA batteries benefit from the ATSAML21J17B-UUT's SleepWalking peripherals. The SAM L21 family data sheet shows that peripherals can wake the CPU only when a meaningful event occurs, keeping idle current at 200 nA. The 128 KB Flash comfortably fits Thread/Zigbee/BLE stacks, while 16 KB SRAM buffers sensor bursts. The wide 1.6 V to 3.6 V supply range works directly from a discharging Li-ion cell without boost circuitry. Integrated 12-bit ADC and SERCOM channels provide direct interfaces to environmental sensors, lowering BOM cost.
Recommended
Smart Metering and Utility Endpoints
Smart electricity, gas, and water meters demand a balance of long battery life, deterministic response, and tamper-resistant storage - all delivered by the ATSAML21J17B-UUT. The Cortex-M0+ runs metering algorithms at 2.46 CoreMark/MHz while active, but stays in deep sleep for the rest of the time. The 128 KB Flash can host metering firmware plus a wireless stack, while 16 KB SRAM retains measurement buffers. Functional Safety (FuSa) features support IEC 62053-style meter designs. The industrial -40C to +85C rating and 1.6 V to 3.6 V supply cover outdoor meter cabinets.
Recommended
Home Automation Hubs and Edge Nodes
Home automation edge nodes such as occupancy sensors, smart thermostats, and BLE/Zigbee coordinators fit the ATSAML21J17B-UUT perfectly. The 128 KB Flash stores the application and wireless stack concurrently, and the Cortex-M0+ 48 MHz can run low-rate encryption and mesh routing. Full-speed USB simplifies commissioning ports, and the SERCOM interfaces can be reconfigured as UART, SPI, or I2C to talk to multiple radios. The compact WLCSP allows the entire node to mount behind a wall switch. Functional Safety features support smoke/CO detector logic where relevant.
Recommended
Remote Controls and Human-Machine Interfaces
Universal remote controls and HMI panels use the ATSAML21J17B-UUT for its combination of low power and rich peripherals. The integrated PTC enables reliable capacitive touch buttons without external ICs, while the Cortex-M0+ 48 MHz runs IR/RF/BLE transmit protocols with low latency. The WLCSP package keeps the BOM small enough for a slim remote housing, and 200 nA Sleep current means a coin-cell can last multiple years with intermittent use. Full-speed USB also supports rechargeable remote designs with firmware update capability.
Recommended
Industrial IoT Sensor Edge Nodes
Industrial IoT edge nodes must operate reliably from -40C to +85C and survive wide voltage transients. The ATSAML21J17B-UUT's industrial temperature grade and 1.6 V to 3.6 V supply handle these conditions. Functional Safety (FuSa) features support safety-related sensing, while the SAM L21 SleepWalking architecture keeps the average current low enough to run from harvested sources. The 64-ball WLCSP allows nodes to mount in tight control cabinets, and the integrated 12-bit ADC simplifies analog sensor interfacing. The 128 KB Flash hosts application code plus OTA update staging.
Recommended
Recommended Products Summary
Engineering reference data for ATSAML21J17B-UUT β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAML21J18B-UUT | ATSAML21J16B-UUT | ATSAMD21J17B-UUT | ATSAML11E16A-UUT |
|---|---|---|---|---|---|
| Package | WLCSP-64 (3.58 x 3.28 mm) | WLCSP-64 (3.58 x 3.28 mm) | WLCSP-64 (3.58 x 3.28 mm) | WLCSP-64 (similar footprint) | WLCSP (lower pin count) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 128 KB | 256 KB | 64 KB | 128 KB | 64 KB |
| SRAM | 16 KB | 32 KB | 8 KB | 16 KB | 16 KB |
| Core | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M0+ | ARM Cortex-M23 |
| Maximum Clock Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Sleep Current (typical) | 200 nA | 200 nA | 200 nA | ~3 uA (higher) | ~500 nA |
| Supply Voltage Range | 1.6 V to 3.6 V | 1.6 V to 3.6 V | 1.6 V to 3.6 V | 1.62 V to 3.63 V | 1.62 V to 3.63 V |
Key Differentiators
- Lowest Sleep current in the SAM L21 family with full 128 KB Flash and 16 KB SRAM (vs ATSAMD21J17B-UUT)
- WLCSP64 footprint shared with the J18B upgrade variant (vs ATSAML21J18B-UUT)
- Functional Safety (FuSa) features for safety-related designs (vs ATSAML21J16B-UUT)
Design Notes
Place a 100 nF X7R 0402 decoupling capacitor as close as possible to each VDD pin and a bulk 4.7 uF ceramic near the IC. The WLCSP64 die sits directly under the balls, so use Microvia-in-Pad (VIP) or tented vias to minimize inductance. Keep the bottom layer as a continuous ground plane beneath the part to support thermal dissipation and reduce EMI.
Estimated: at 48 MHz active across all peripherals and 3.3 V supply, the ATSAML21J17B-UUT draws under 35 uA/MHz, so power dissipation is roughly 6 mW (P = V x I). Junction temperature rise above ambient is small (<2 C) and no heatsink is required. However, in sealed enclosures with no airflow, derate ambient temperature by 5-10 C to stay within the 85 C industrial ceiling.
Configure unused pins as outputs driving a defined logic level (not inputs) to eliminate shoot-through current on floating pads. Always enable the brown-out detector (BOD) in fuses to avoid Flash corruption during brown-out. Do not exceed 50 pF on the XIN/XOUT crystal traces, and keep the crystal within 5 mm of the IC to minimize parasitic capacitance.
SERCOM I/O pads operate in I/O banks that share a common VDDIO rail; if you mix 1.8 V and 3.3 V peripherals, split the bank supplies accordingly. For USB, the DP/DM traces must be 90 ohm differential with length matching to within 150 mil. Add a common-mode choke on DP/DM near the connector to pass EN 55032 radiated emissions.
Compliance Information
Mouser listing indicates IND TEMP GREEN, 1.6-3.6V, 48MHz - Green indicates RoHS/REACH compliant. AEC-Q100 not applicable; for automotive-grade SAM L21, see the ATSAML21E variant.
