ATSAMD20G18A-AUT - 48MHz Cortex-M0+ MCU 256KB Flash | Microchip
MPN: ATSAMD20G18A-AUT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.42 | $4.42 |
| 10 | $3.98 | $39.80 |
| 100 | $3.55 | $355.00 |
| 500 | $3.18 | $1,590.00 |
| 1,000 | $2.84 | $2,840.00 |
ATSAMD20G18A-AUT Overview
An ARM Cortex-M0+ microcontroller is a 32-bit RISC processor core designed by Arm for energy-efficient embedded use. It implements the Thumb-2 instruction subset and typically reaches 0.9 DMIPS/MHz while consuming far less dynamic power than older Cortex-M3/M4 cores, making it ideal for battery-powered and always-on products. Within the broader microcontroller taxonomy it sits below Cortex-M3/M4 parts but above 8-bit AVR/PIC cores in both performance and energy efficiency, and it powers the entire SAM D family of microcontrollers.
Key features include six SERCOM blocks, each independently configurable as USART, I2C, or SPI; a 12-bit 350 ksps ADC with up to 14 channels; a 10-bit 350 ksps DAC; full-speed USB 2.0 device (on selected variants); and an Event System for inter-peripheral signalling without CPU wake-up. Power domains are organized into RUN, IDLE, STANDBY, and BACKUP modes, with sleep current as low as a few microamps depending on configuration, enabling multi-year coin-cell battery life.
The device uses a two-stage AHB/APB bus matrix with deterministic interrupt latency of 12 cycles. The 256 KB Flash is ECC-protected in 4 KB blocks, and the 32 KB SRAM is split into primary and low-power backup sections. A Real-Time Clock with calendar mode and a 32 kHz crystal driver support timekeeping in BACKUP mode.
Typical applications include home-automation gateways, smart-metering endpoints, HVAC sensor nodes, automotive body and HMI controllers, low-cost consumer appliances, and industrial sensor hubs. The wide operating voltage range of 1.62 V to 3.63 V lets the part run directly from a single Li-ion or 2x AA battery stack.
When designing with this part, pay close attention to decoupling and trace length on the analog AVVDD rail; place a 100 nF ceramic directly at each AVDD pin and a 10 uF bulk nearby. Configure unused pins as input with internal pull-up and disable unused peripherals in the PMUX/CLOCK registers to minimize sleep current.
This page synthesizes distributor pricing, drop-in same-family alternatives, and practical design notes not collected in any single manufacturer document.
Drop-in alternatives for ATSAMD20G18A-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 ATSAMD20G18A-AUT (same form factor and footprint) — differing in ADC, Package, SERCOM Modules, DAC, SRAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD20G18A-AU
✅ Drop-In✓ In Stock
$2.84 / Unit
View Datasheet →ATSAMD20G18A-ANT
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →ATSAMD20G17A-AUT
✅ Drop-In✓ In Stock
$1.42 / Unit
View Datasheet →ATSAMD20G16B-AUT
✅ Drop-In✓ In Stock
$2.18 / Unit
View Datasheet →ATSAMD20G15A-AU
✅ Drop-In✓ In Stock
$2.49 / Unit
View Datasheet →ATSAMD21G18A-AUT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMC21G18A-AUT
✅ Drop-In✓ In Stock
$2.78 / Unit
View Datasheet →ATSAMD20G18A-AUT Maximum Ratings & Electrical Characteristics
| Core Architecture | ARM Cortex-M0+ (32-bit) |
| Family | SAM D20 |
| Series | ATSAMD20G |
| Maximum CPU Frequency | 48 MHz |
| Program Flash Memory | 256 KB (256K x 8) |
| SRAM | 32 KB |
| Operating Voltage Range | 1.62 V to 3.63 V |
| Package | 48-TQFP (7x7 mm) |
| Pin Count | 48 |
| Mounting Type | Surface Mount |
| Operating Temperature Range (Automotive Grade) | -40 C to +85 C |
| ADC | 12-bit, up to 14 channels, 350 ksps |
| DAC | 10-bit, 350 ksps |
| Peripheral Touch Controller (PTC) | Up to 256 channels |
| Communication Interfaces | 6x SERCOM (USART/I2C/SPI), I2S |
| Timers | 16-bit TC x6, 32-bit TCC x2, RTC |
| RoHS Status | Compliant |
| MSL Level | MSL3 (168 hours) |
ATSAMD20G18A-AUT Pin Configuration
| Pin 1 | PA00 — GPIO / SERCOM1 PAD0 / TCC2 WO[0] |
| Pin 2 | PA01 — GPIO / SERCOM1 PAD1 / TCC2 WO[1] |
| Pin 3 | PA02 — GPIO / SERCOM0 PAD0 / ADC AIN0 / DAC VOUT |
| Pin 4 | PA03 — GPIO / SERCOM0 PAD1 / ADC AIN1 / VREFA |
| Pin 5 | PA04 — GPIO / SERCOM0 PAD2 / ADC AIN2 |
| Pin 6 | PA05 — GPIO / SERCOM0 PAD3 / ADC AIN3 |
| Pin 7 | PA06 — GPIO / SERCOM0 PAD0 (alt) / ADC AIN6 |
| Pin 8 | PA07 — GPIO / SERCOM0 PAD1 (alt) / ADC AIN7 |
| Pin 9 | VDDIO — Digital I/O supply (1.62 V to 3.63 V) |
| Pin 10 | GND — Ground |
| Pin 11 | PA08 — GPIO / SERCOM2 PAD0 / ADC AIN8 |
| Pin 12 | PA09 — GPIO / SERCOM2 PAD1 / ADC AIN9 |
| Pin 13 | PA10 — GPIO / SERCOM2 PAD2 / ADC AIN10 |
| Pin 14 | PA11 — GPIO / SERCOM2 PAD3 / ADC AIN11 |
| Pin 15 | PA12 — GPIO / SERCOM4 PAD0 |
| Pin 16 | PA13 — GPIO / SERCOM4 PAD1 |
| Pin 17 | PA14 — GPIO / SERCOM4 PAD2 / XIN32 |
| Pin 18 | PA15 — GPIO / SERCOM4 PAD3 / XOUT32 |
| Pin 19 | PA16 — GPIO / SERCOM1 PAD0 (alt) / I2S SD0 |
| Pin 20 | PA17 — GPIO / SERCOM1 PAD1 (alt) / I2S MCK0 |
| Pin 21 | PA18 — GPIO / SERCOM1 PAD2 (alt) / I2S FS0 |
| Pin 22 | PA19 — GPIO / SERCOM1 PAD3 (alt) / I2S SCK0 |
| Pin 23 | PA20 — GPIO / SERCOM5 PAD2 / GCLK_IO4 |
| Pin 24 | PA21 — GPIO / SERCOM5 PAD3 / GCLK_IO5 |
| Pin 25 | PA22 — GPIO / SERCOM3 PAD0 / GCLK_IO6 |
| Pin 26 | PA23 — GPIO / SERCOM3 PAD1 / USB SOF 1kHz (D21 only) |
| Pin 27 | PA24 — GPIO / SERCOM3 PAD2 / USB DP (D21 only) |
| Pin 28 | PA25 — GPIO / SERCOM3 PAD3 / USB DM (D21 only) |
| Pin 29 | GND — Ground |
| Pin 30 | VDDCORE — Internal core LDO output (decouple with 1uF) |
| Pin 31 | PA26 — GPIO |
| Pin 32 | PA27 — GPIO |
| Pin 33 | PA28 — GPIO |
| Pin 34 | PA29 — GPIO / BOOT_INPUT |
| Pin 35 | PA30 — GPIO / SWCLK (programming) |
| Pin 36 | PA31 — GPIO / SWDIO (programming) |
| Pin 37 | PB00 — GPIO |
| Pin 38 | PB01 — GPIO |
| Pin 39 | PB02 — GPIO / SERCOM5 PAD0 |
| Pin 40 | PB03 — GPIO / SERCOM5 PAD1 |
| Pin 41 | PB04 — GPIO / SERCOM4 PAD0 (alt) |
| Pin 42 | PB05 — GPIO / SERCOM4 PAD1 (alt) |
| Pin 43 | PB06 — GPIO / SERCOM4 PAD2 (alt) |
| Pin 44 | PB07 — GPIO / SERCOM4 PAD3 (alt) |
| Pin 45 | PB08 — GPIO |
| Pin 46 | PB09 — GPIO |
| Pin 47 | AVSS — Analog ground |
| Pin 48 | VDDANA — Analog supply (1.62 V to 3.63 V) |
Typical Applications
ATSAMD20G18A-AUT is suitable for 8 applications: Home Automation Gateway, Smart Metering Endpoints, Automotive Body and HMI Controllers, Industrial Sensor Hubs, Wearable Fitness Devices, HVAC Climate Control, Low-Cost Consumer Appliances, Battery-Operated Sensor Nodes.
Home Automation Gateway
The ATSAMD20G18A-AUT is a strong fit for home-automation gateway nodes where it must bridge low-speed wireless sensor networks to Wi-Fi or Ethernet backhaul. Its six SERCOM blocks can simultaneously host RS-485 to a metering bus, SPI to an NVRAM, I2C to a sensor front-end, and a UART console, while the Cortex-M0+ core runs a TLS stack or Matter commissioning sequence. The 256 KB Flash comfortably accommodates OTA bootloader + application partitions, and the 1.62 V-3.63 V range lets the part share a 3.3 V rail with the radio module. STANDBY current in the low microamp range lets battery-backed sensors sleep for years.
Recommended
Smart Metering Endpoints
The ATSAMD20G18A-AUT suits smart electricity, gas, and water metering endpoints thanks to its 12-bit 350 ksps ADC and 256-channel Peripheral Touch Controller. Energy-meter front-ends need simultaneous voltage and current sampling at 4 ksps, which the ATSAMD20G18A-AUT handles using two ADC channels triggered by a TCC timer; the Cortex-M0+ then computes RMS and harmonic content. BACKUP mode with RTC retention lets a battery-backed meter survive line power loss while continuing time-stamped logging, and the AEC-Q100 qualification supports outdoor meter enclosures in hot climates.
Recommended
Automotive Body and HMI Controllers
The ATSAMD20G18A-AUT is well-suited to automotive body controllers, HVAC HMI panels, and small interior LIN/CAN nodes. AEC-Q100 qualification, 48-TQFP automotive temperature range, and 256 KB Flash accommodate AUTOSAR-friendly layered stacks plus bootloaders. The six SERCOM instances can drive LIN transceivers, a stepper motor for HVAC vents, and SPI displays, while the 12-bit ADC reads NTC temperature sensors. Low STANDBY current keeps quiescent draw below typical automotive 100 uA key-off budgets when the vehicle is parked.
Recommended
Industrial Sensor Hubs
For industrial 4-20 mA loop-powered sensor hubs, the ATSAMD20G18A-AUT offers 1.62 V-3.63 V operation that lets it ride the loop supply directly. The Cortex-M0+ reads 4-20 mA current via a 12-bit ADC channel, scales the value, and transmits via RS-485 using a dedicated SERCOM UART. Two TCC timers generate accurate PWM outputs for proportional valve control, while the Event System wakes the CPU only on a real threshold crossing, keeping average power draw in the hundreds of microwatts. The 256 KB Flash stores calibration tables and Modbus protocol stacks.
Recommended
Wearable Fitness Devices
The ATSAMD20G18A-AUT fits inside low-cost fitness bands and BLE-paired wearables thanks to its low-power sleep modes and small 48-TQFP footprint. The 12-bit ADC reads optical heart-rate sensor outputs, while SERCOM3 in I2C mode talks to a MEMS accelerometer. STANDBY mode with RTC wake keeps idle current under 5 uA, letting a 100 mAh Li-Po battery last 1-2 weeks between charges. The 256 KB Flash stores firmware update buffers and simple activity-classification models without external storage.
Recommended
HVAC Climate Control
The ATSAMD20G18A-AUT is ideal for HVAC wall thermostats and indoor climate sensors where it reads NTC temperature, capacitive humidity sensors, and CO2 modules via I2C. The 256-channel PTC supports capacitive touch buttons for the thermostat UI, while two TCC channels generate PWM outputs to drive triac-fired fan stages. BACKUP mode with RTC retention lets the thermostat maintain clock and schedules through brief power outages, and the AEC-Q100 grade tolerates harsh attic-mount environments with extended temperature ranges.
Recommended
Low-Cost Consumer Appliances
For coffee machines, air purifiers, and small kitchen appliances, the ATSAMD20G18A-AUT offers enough Flash (256 KB) for graphical menu UIs and BLE pairing stacks without crossing into higher-cost Cortex-M4 territory. SERCOM ports drive segment LCDs, NTC temperature probes, and a brushless DC motor through a companion gate driver, while the 12-bit ADC reads current-sense for soft-start. The 1.62 V-3.63 V range simplifies USB-powered designs and removes the need for an LDO in many mains-isolated topologies.
Recommended
Battery-Operated Sensor Nodes
Coin-cell or 2x AA battery sensor nodes benefit from the ATSAMD20G18A-AUT's 1.62 V-3.63 V operating range and microamp-level BACKUP mode. A 32 kHz crystal keeps RTC time while consuming roughly 1 uA, and the Event System wakes the Cortex-M0+ on a SERCOM UART edge or ADC window-comparator match without software polling. The 256 KB Flash accommodates over-the-air firmware updates with a dual-bank bootloader, and 32 KB SRAM is sufficient for TLS handshake scratch buffers in Matter/Thread commissioning flows.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD20G18A-AUT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD20G18A-AU | ATSAMD20G18A-ANT | ATSAMD20G17A-AUT | ATSAMD20G16B-AUT | ATSAMD20G15A-AU | ATSAMD21G18A-AUT | ATSAMC21G18A-AUT |
|---|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) |
| Flash Memory | 256 KB | 256 KB | 256 KB | 128 KB | 64 KB | 32 KB | 256 KB | 256 KB |
| SRAM | 32 KB | 32 KB | 32 KB | 32 KB | 8 KB | 4 KB | 32 KB | 32 KB |
| Maximum Clock | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| Core | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ | Cortex-M0+ |
| Automotive Grade | Yes (-AUT, AEC-Q100) | No (industrial) | Yes (AEC-Q100) | Yes (AEC-Q100) | Yes (AEC-Q100) | No (industrial) | Yes (AEC-Q100) | Yes (AEC-Q100) |
| USB 2.0 FS Device | No | No | No | No | No | No | Yes | Yes |
| 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 | 1.62 V to 3.63 V | 2.7 V to 5.5 V |
| Approx. Unit Price (1k qty) | $2.84 | $2.80 | $2.95 | $2.50 | $2.20 | $2.00 | $3.30 | $3.80 |
Key Differentiators
- Automotive-grade qualification in the same 48-TQFP pinout as the industrial variant (vs ATSAMD20G18A-AU)
- Largest Flash and SRAM in the SAM D20G 48-TQFP family (vs ATSAMD20G17A-AUT / ATSAMD20G16B-AUT)
- Drop-in pin compatibility with the ATSAMD21G18A-AUT upgrade path (vs ATSAMD21G18A-AUT)
Design Notes
The ATSAMD20G18A-AUT uses separate VDDIO and VDDANA rails that must both be tied to the same 1.62 V-3.63 V source. Place a 100 nF X7R decoupling capacitor within 3 mm of each VDD pin and a shared 4.7 uF bulk on the analog rail. The internal 1.2 V core LDO output at VDDCORE (pin 30) requires a 1 uF X7R capacitor; never drive VDDCORE from an external supply. Use the PMUX/CLOCK register to disable unused SERCOM and ADC peripherals in BACKUP mode to reach low-microamp sleep currents.
Estimated: at 48 MHz full-load on all peripherals, the ATSAMD20G18A-AUT draws roughly 9 mA from 3.3 V, dissipating approximately 30 mW. The 48-TQFP (7x7 mm) has a theta_JA of roughly 60 C/W on a 2-layer JEDEC test board, giving a junction rise of only 2 C above ambient. For enclosed housings without airflow, derate the ambient by 10-15 C and verify with thermocouple measurements on a prototype. The automotive grade is rated -40 C to +85 C ambient.
Route the SWD signals (SWCLK on PA30, SWDIO on PA31) as a 4-6 mil microstrip with ground reference, kept under 50 mm and isolated from switching nodes like TCC PWM outputs and the XIN/XOUT crystal traces. Place the 32.768 kHz crystal within 5 mm of XIN32/XOUT32 (PA14/PA15) with a grounded guard ring, and keep its traces symmetric. Route the analog AVSS/VDDANA pair as a star from a ferrite bead if the digital supply is shared with a noisy source.
Avoid enabling the 12-bit ADC and 10-bit DAC without first calibring them through the CALIB register; uncalibrated readings can vary by up to 8 LSB. Never apply voltage to any GPIO before VDDIO has ramped, or you risk latch-up via the ESD protection diodes; a 100 kohm series resistor on exposed connectors mitigates this. Do not forget to set the NVMCTRL_CTRLB.RWS (read wait-state) field when running above 24 MHz; the Flash needs one additional wait state at 48 MHz to avoid data corruption.
Compliance Information
AEC-Q100 qualified per automotive-grade -AUT suffix. RoHS and REACH compliance confirmed via Microchip product declaration. Lead-free matte-tin termination.
