ATSAML21J16B-AUT - 48MHz Cortex-M0+ MCU 64KB Flash | Microchip
MPN: ATSAML21J16B-AUT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.1 | $7.10 |
| 10 | $6.4 | $64.00 |
| 100 | $5.5 | $550.00 |
| 500 | $4.85 | $2,425.00 |
| 1,000 | $4.25 | $4,250.00 |
ATSAML21J16B-AUT Overview
A microcontroller (MCU) is an integrated circuit that combines a CPU core, program memory, data RAM, and peripherals on a single silicon die. The ARM Cortex-M0+ is the smallest and most energy-efficient ARM processor core, optimized for deterministic embedded control with a minimal instruction set, while the SAM L21 family extends this with sophisticated power-domain gating. Within the broader hierarchy, this part sits at MCU -> 32-bit MCU -> Cortex-M0+ MCU -> Ultra-Low-Power MCU -> Power Management Aware MCU.
Key features include the Cortex-M0+ core at 48MHz delivering 2.46 CoreMark/MHz, 64KB embedded Flash, 8KB SRAM, and an integrated full-speed USB 2.0 device with on-chip transceiver. The device also integrates a 12-bit 1MSPS ADC, multiple SERCOM peripherals configurable as UART/SPI/I2C, a 32-bit RTC, and a segmented LCD controller with up to 8x32 segments. The wide 1.62V to 3.63V supply range and on-chip DC-DC buck converter enable direct battery operation from a single 1.5V cell when boosted, or from a 3V coin cell.
Typical applications include wearable fitness bands, medical sensor patches, smart remote controls, IoT sensor nodes, battery-powered metering, and human-machine interface panels with LCD readouts. The integrated LCD controller makes the SAM L21 especially attractive for industrial gauges and consumer devices that need a low-power alphanumeric or segment display alongside processing.
When designing with this MCU, place a 1µF decoupling capacitor on each VDD pin and keep the 32.768kHz crystal traces short to minimize sleep-mode current. Use the SAM L21 sleepwalking peripheral to wake the CPU only on sensor thresholds, which is the key to achieving the 200nA sleep figure. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATSAML21J16B-AUT — 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 ATSAML21J16B-AUT (same form factor and footprint) — differing in Package, ADC, SRAM, DAC, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAML21J17B-AUT
✅ Drop-In✓ In Stock
$2.98 / Unit
View Datasheet →ATSAML21J18B-AUT
✅ Drop-In✓ In Stock
$4.55 / Unit
View Datasheet →ATSAML21J16B-MUT
✅ Drop-In✓ In Stock
$2.18 / Unit
View Datasheet →ATSAML21J16B-ANT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAML21E16B-MUT
✅ Drop-In✓ In Stock
$2.3 / Unit
View Datasheet →ATSAML21G17B-ANT
✅ Drop-In✓ In Stock
$2.71 / Unit
View Datasheet →ATSAML21J16B-AUT Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ 32-bit |
| Maximum CPU Frequency | 48 MHz |
| Flash Memory | 64 KB (64K x 8) |
| SRAM | 8 KB |
| Package | TQFP-64 (10x10 mm) |
| Operating Voltage Range | 1.62 V to 3.63 V |
| Active Mode Current | <35 µA/MHz |
| Sleep Mode Current | 200 nA (typical) |
| Operating Temperature Range | -40 °C to +85 °C (industrial) |
| ADC | 12-bit, 1 MSPS |
| USB | USB 2.0 Full-Speed Device with on-chip transceiver |
| SERCOM Peripherals | Configurable as UART/SPI/I2C |
| RTC | 32-bit Real-Time Clock |
| LCD Controller | Integrated, up to 8x32 segments |
| CoreMark/MHz | 2.46 |
| Carrier Type | Tape & Reel |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
ATSAML21J16B-AUT Pin Configuration
| Pin 1 | PA00 — GPIO / XIN32 / SERCOM1[0] |
| Pin 2 | PA01 — GPIO / XOUT32 / SERCOM1[1] |
| Pin 3 | PA02 — GPIO / AIN0 / SERCOM0[0] |
| Pin 4 | PA03 — GPIO / AIN1 / SERCOM0[1] |
| Pin 5 | VDDIO — I/O supply voltage |
| Pin 6 | VSS — Ground |
| Pin 7 | PA04 — GPIO / AIN2 / SERCOM0[2] |
| Pin 8 | PA05 — GPIO / AIN3 / SERCOM0[3] |
| Pin 9 | PA06 — GPIO / AIN4 / SERCOM2[0] |
| Pin 10 | PA07 — GPIO / AIN5 / SERCOM2[1] |
| Pin 11 | PA08 — GPIO / AIN6 / SERCOM2[2] |
| Pin 12 | PA09 — GPIO / AIN7 / SERCOM2[3] |
| Pin 13 | PA10 — GPIO / AIN8 / SERCOM0[2] |
| Pin 14 | PA11 — GPIO / AIN9 / SERCOM0[3] |
| Pin 15 | VDD — Core supply voltage |
| Pin 16 | VSS — Ground |
| Pin 17 | PB10 — GPIO / SERCOM4[2] |
| Pin 18 | PB11 — GPIO / SERCOM4[3] |
| Pin 19 | PB12 — GPIO / SERCOM4[0] |
| Pin 20 | PB13 — GPIO / SERCOM4[1] |
| Pin 21 | PB14 — GPIO / SERCOM5[2] |
| Pin 22 | PB15 — GPIO / SERCOM5[3] |
| Pin 23 | PA12 — GPIO / SERCOM4[0] |
| Pin 24 | PA13 — GPIO / SERCOM4[1] |
| Pin 25 | PA14 — GPIO / SERCOM2[0] |
| Pin 26 | PA15 — GPIO / SERCOM2[1] |
| Pin 27 | PA16 — GPIO / SERCOM1[0] |
| Pin 28 | PA17 — GPIO / SERCOM1[1] |
| Pin 29 | PA18 — GPIO / SERCOM1[2] |
| Pin 30 | PA19 — GPIO / SERCOM1[3] |
| Pin 31 | PA20 — GPIO / SERCOM5[2] |
| Pin 32 | PA21 — GPIO / SERCOM5[3] |
| Pin 33 | PA22 — GPIO / SERCOM3[0] |
| Pin 34 | PA23 — GPIO / SERCOM3[1] |
| Pin 35 | PA24 — GPIO / SERCOM3[2] / USB_DM |
| Pin 36 | PA25 — GPIO / SERCOM3[3] / USB_DP |
| Pin 37 | PB16 — GPIO / SERCOM5[0] |
| Pin 38 | PB17 — GPIO / SERCOM5[1] |
| Pin 39 | PA27 — GPIO / SERCOM3[3] |
| Pin 40 | RESET — Reset input, active low |
| Pin 41 | VDD — Core supply voltage |
| Pin 42 | VSS — Ground |
| Pin 43 | PA28 — GPIO / SERCOM5[0] |
| Pin 44 | PA29 — GPIO / SERCOM5[1] |
| Pin 45 | PA30 — GPIO / SERCOM1[2] |
| Pin 46 | PA31 — GPIO / SERCOM1[3] |
| Pin 47 | PB22 — GPIO / SERCOM5[2] |
| Pin 48 | PB23 — GPIO / SERCOM5[3] |
| Pin 49 | PB30 — GPIO / SERCOM5[0] |
| Pin 50 | PB31 — GPIO / SERCOM5[1] |
| Pin 51 | PB00 — GPIO / AIN8 / SERCOM5[2] |
| Pin 52 | PB01 — GPIO / AIN9 / SERCOM5[3] |
| Pin 53 | PB02 — GPIO / AIN10 / SERCOM5[0] |
| Pin 54 | PB03 — GPIO / AIN11 / SERCOM5[1] |
| Pin 55 | VDDIO — I/O supply voltage |
| Pin 56 | VSS — Ground |
| Pin 57 | PB04 — GPIO / SERCOM3[0] |
| Pin 58 | PB05 — GPIO / SERCOM3[1] |
| Pin 59 | PB06 — GPIO / SERCOM3[2] |
| Pin 60 | PB07 — GPIO / SERCOM3[3] |
| Pin 61 | PB08 — GPIO / SERCOM4[0] |
| Pin 62 | PB09 — GPIO / SERCOM4[1] |
| Pin 63 | SWDIO — Debug data |
| Pin 64 | SWCLK — Debug clock |
Typical Applications
ATSAML21J16B-AUT is suitable for 6 applications: Wearable Fitness Tracker, Battery-Powered IoT Sensor Node, Industrial Metering and LCD Display, Medical Sensor Patch, Smart Remote Control, Human-Machine Interface Panel.
Wearable Fitness Tracker
The ATSAML21J16B-AUT's 200nA Sleep current and sub-35µA/MHz active draw make it ideal for coin-cell-powered wearable fitness bands. Per the SAM L21 datasheet DS60001477C, the integrated 12-bit ADC paired with SERCOM peripherals reads heart-rate optical sensors and accelerometer data at low duty cycle, while the integrated LCD controller drives the segment display showing steps, time, and notifications without waking the core. Compared to Cortex-M4 alternatives, the L21 extends battery life by 30-50% at typical activity tracking workloads.
Recommended
Battery-Powered IoT Sensor Node
For IoT sensor nodes that must run months on a single battery, the ATSAML21J16B-AUT provides the right combination of low sleep current and integrated peripherals. The SAM L21's sleepwalking peripherals wake the CPU only when a sensor threshold is crossed, eliminating polling overhead. The integrated full-speed USB 2.0 allows direct firmware update from any USB host, while the 1.62V-3.63V supply range supports direct 3V lithium primary cells. Per Microchip product page, this part is qualified for industrial IoT deployments.
Recommended
Industrial Metering and LCD Display
The ATSAML21J16B-AUT's integrated segmented LCD controller (up to 8x32 segments) eliminates the need for an external LCD driver in industrial metering applications such as electricity, gas, or water meters. Per the SAM L21 datasheet, the LCD controller supports static, 1/2, 1/3, and 1/4 bias with charge pump, and operates in deep-sleep modes with the CPU stopped. The 200nA Sleep current with LCD active makes 10-year battery life achievable on metrology designs using a single lithium cell.
Recommended
Medical Sensor Patch
For disposable and reusable medical sensor patches (continuous glucose monitors, temperature loggers, ECG patches), the ATSAML21J16B-AUT delivers the ultra-low power required for multi-day operation. The Cortex-M0+ core is sufficient for sensor signal conditioning and BLE control while consuming under 35 µA/MHz per Microchip product page data. The on-chip DC-DC converter maintains efficiency across the full battery discharge curve, and the integrated RTC with calendar supports accurate timestamping for medical compliance records.
Recommended
Smart Remote Control
The ATSAML21J16B-AUT fits smart remote controls that need long battery life, USB charging, and an LCD or LED status display. The integrated USB 2.0 Full-Speed device supports direct firmware update and charging from any TV USB port. SERCOM peripherals handle IR transmission, BLE control links, and capacitive touch sensing. Per the SAM L21 datasheet, the part can wake from sleep on touch interrupt in under 5 µs, delivering the responsive feel users expect from premium remote controls.
Recommended
Human-Machine Interface Panel
For HMI panels with LCD displays and tactile button input, the ATSAML21J16B-AUT's integrated segmented LCD controller and SERCOM peripherals support both display driving and button matrix scanning. Per the SAM L21 datasheet DS60001477C, the 1MSPS 12-bit ADC enables precise analog input reading for rotary encoders or resistive touch overlays. The 48MHz Cortex-M0+ core runs the GUI state machine with 2.46 CoreMark/MHz headroom, leaving resources for application logic and BLE/Wi-Fi connectivity.
Recommended
Recommended Products Summary
Engineering reference data for ATSAML21J16B-AUT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAML21J17B-AUT | ATSAML21J18B-AUT | ATSAML21J16B-MUT | ATSAML21J16B-ANT |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | TQFP-64 (10x10 mm) | TQFP-64 (10x10 mm) - same | TQFP-64 (10x10 mm) - same | QFN-64 - different footprint | TQFP-64 (10x10 mm) - same |
| Flash Memory | 64 KB | 128 KB | 256 KB | 64 KB | 64 KB |
| SRAM | 8 KB | 16 KB | 40 KB | 8 KB | 8 KB |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +105 °C |
| Maximum Clock Speed | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Sleep Current (typ) | 200 nA | 200 nA | 200 nA | 200 nA | 200 nA |
| Integrated USB | Yes (Full-Speed) | Yes (Full-Speed) | Yes (Full-Speed) | Yes (Full-Speed) | Yes (Full-Speed) |
Key Differentiators
- Ultra-low-power Sleep with on-chip DC-DC converter (vs ATSAMD21J16B-AFT)
- Integrated segmented LCD controller (vs ATSAML21E16B-MUT)
- Drop-in memory upgrade path within same package (vs ATSAML21J16B-MUT)
Design Notes
Estimated: At VDD = 3.3V, active CPU core current draw is approximately 35 µA/MHz × 48 MHz = 1.68 mA. Add 10-50 µA for ADC conversions and 1-2 mA peaks during USB transactions. In Sleep mode the part draws 200nA typical per the SAM L21 datasheet, but the integrated segmented LCD controller with all segments enabled adds approximately 1-2 µA. Place a 1µF X7R ceramic decoupling capacitor on each VDD/VDDIO pin within 2mm of the pin to maintain stable supply during DC-DC converter switching transients.
Keep the 32.768kHz crystal traces short (less than 5mm) and symmetric to avoid duty-cycle distortion. Route the USB D+/D- traces as a 90-ohm differential pair with no stubs, and place the 27-ohm series termination resistors close to the MCU. The exposed thermal pad on the TQFP-64 package (when present) should be soldered to a ground copper pour with thermal vias for heat dissipation, although the SAM L21 generates minimal heat at typical operating currents.
Do not exceed the absolute maximum VDDIO of 4.0V - the on-chip DC-DC converter and Flash are rated to 3.63V maximum. The SEG pins used for the LCD controller must be configured correctly before enabling the peripheral, otherwise segment ghosting occurs. When using the SERCOM peripherals, verify that the I/O pin assignments do not conflict with the LCD segment pins, as many pins are multiplexed. Use Microchip's START code generator to validate pin multiplexing before PCB layout.
Compliance Information
RoHS and REACH compliance per Microchip product page. Industrial grade only; not AEC-Q100 automotive qualified - choose ATSAML21E16B-AUT automotive variants for vehicle applications.
