ATSAMD20E18A-MU - 48MHz ARM Cortex-M0+ 256KB Flash MCU | Microchip
MPN: ATSAMD20E18A-MU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.4 | $4.40 |
| 10 | $3.96 | $39.60 |
| 100 | $3.52 | $352.00 |
| 500 | $3.09 | $1,545.00 |
| 1,000 | $2.75 | $2,750.00 |
ATSAMD20E18A-MU Overview
An ARM Cortex-M0+ microcontroller is an entry-level 32-bit MCU that delivers higher code density and energy efficiency than legacy 8-bit/16-bit microcontrollers while retaining a familiar programmer model. Within the product taxonomy, the Cortex-M0+ sits between Cortex-M0 and Cortex-M3 in the ARM Cortex-M family; the SAM D20E specifically belongs to Microchip's SAM D20 series, which is positioned for low-power, general-purpose 32-bit designs spanning home automation, consumer, metering, and industrial control applications. The integration of 256KB Flash and 32KB SRAM in a 5x5 mm VQFN makes the family attractive where code size and PCB area are tight.
Key features include 256KB Flash (256K x 8), 32KB SRAM, up to 48MHz CPU clock, an integrated peripheral touch controller (PTC) supporting sliders, buttons, and proximity sensing, and the standard SAM D20 SERCOM module count for I2C, SPI, and UART operation. The part also provides a 12-bit ADC, 10-bit DAC, multiple timers (TC, TCC), and a full-speed USB 2.0 device interface. Typical I/O count for the 32-pin variant supports up to 26 GPIO lines.
Architecturally, the device uses a single-cycle hardware multiplier and a tightly coupled memory controller to deliver efficient Cortex-M0+ execution at up to 2.14 CoreMark/MHz. The integrated SleepWalking peripheral event system allows selected peripherals to wake the core only when needed, which contributes to the SAM D20 series' reputation for low standby current and Idle/Standby modes consuming microamp-level current.
Typical applications include smart-home sensor hubs, low-power industrial controllers, USB-to-UART bridges, battery-powered metering devices, and human-machine interface (HMI) controllers using touch or segment-LCD fronts. The combination of 256KB Flash and the extended SAM D20 peripheral set is well matched to connected appliances and IoT edge nodes that must run a small RTOS or bare-metal state machine.
When designing with this part, confirm that your firmware stack (startup, linker script, and ASF/MPLAB Harmony configuration) targets the SAM D20E variant and the 256KB Flash size. Pay attention to decoupling of the exposed thermal pad for thermal performance, and review the recommended load capacitance on the 32kHz crystal if RTC accuracy is critical.
This page synthesizes verified distributor pricing, drop-in pin-compatible alternatives from the SAMD20 family, and practical design notes not found on a single manufacturer page - giving procurement, FAE, and design engineers one place to evaluate and substitute ATSAMD20E18A-MU.
Drop-in alternatives for ATSAMD20E18A-MU — 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 ATSAMD20E18A-MU (same form factor and footprint) — differing in Package, SRAM, ADC, MSL Level, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAMD20E18A-MUT
✅ Drop-In📋 Reference alternative (not in catalog)
ATSAMD20E18A-MNT
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.48 / Unit
View Datasheet →ATSAMD20E16B-MU
✅ Drop-In✓ In Stock
$1.95 / Unit
View Datasheet →ATSAMD20E17A-AN
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.4 / Unit
View Datasheet →ATSAMD20E15B-MU
✅ Drop-In✓ In Stock
$1.1 / Unit
View Datasheet →ATSAMD20E18A-MU Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0+ |
| Core Architecture | ARM 32-bit |
| Instruction Set | Thumb/Thumb-2 |
| Maximum CPU Frequency | 48 MHz |
| Program Memory (Flash) | 256 KB (256K x 8) |
| SRAM | 32 KB (32K x 8) |
| Supply Voltage (Vdd) | 1.62 V to 3.63 V |
| Operating Temperature | -40 C to +85 C |
| Package | 32-VQFN (5x5 mm) with Exposed Pad |
| Mounting Type | Surface Mount |
| I/O Voltage | 3.3 V (typ) |
| Performance | 2.14 CoreMark/MHz |
| Peripheral Touch Controller (PTC) | Yes |
| SERCOM Modules | Up to 6 (I2C/SPI/UART configurable) |
| ADC / DAC | 12-bit ADC / 10-bit DAC (per SAM D20 family) |
| USB | Full-Speed USB 2.0 Device (per SAM D20 family) |
| MSL Level | MSL3 (per Microchip package profile) |
| Lead-Free / RoHS | Yes / Compliant (per Microchip product page) |
| Moisture Sensitivity Floor Life | 168 hours |
ATSAMD20E18A-MU Pin Configuration
| Pin 1 | PB07 — General purpose I/O / SERCOM / TC |
| Pin 2 | PB08 — General purpose I/O / SERCOM / TC |
| Pin 3 | PB09 — General purpose I/O / SERCOM / TC |
| Pin 4 | PA00 — General purpose I/O / SERCOM0 / ADC |
| Pin 5 | PA01 — General purpose I/O / SERCOM0 / ADC |
| Pin 6 | PA02 — General purpose I/O / SERCOM0 / ADC |
| Pin 7 | PA03 — General purpose I/O / SERCOM0 / ADC / REF |
| Pin 8 | GND — Common ground |
| Pin 9 | PA04 — General purpose I/O / SERCOM0 / ADC / VREF |
| Pin 10 | PA05 — General purpose I/O / SERCOM0 / ADC |
| Pin 11 | PA06 — General purpose I/O / SERCOM0 / ADC |
| Pin 12 | PA07 — General purpose I/O / SERCOM0 / ADC |
| Pin 13 | PA08 — General purpose I/O / SERCOM2 / I2C |
| Pin 14 | PA09 — General purpose I/O / SERCOM2 / I2C |
| Pin 15 | PA10 — General purpose I/O / SERCOM2 |
| Pin 16 | PA11 — General purpose I/O / SERCOM2 |
| Pin 17 | VDDIO — I/O supply voltage |
| Pin 18 | GND — Common ground |
| Pin 19 | PA14 — General purpose I/O / SERCOM2 |
| Pin 20 | PA15 — General purpose I/O / SERCOM2 / TC |
| Pin 21 | PA16 — General purpose I/O / SERCOM1 / TC |
| Pin 22 | PA17 — General purpose I/O / SERCOM1 / TC |
| Pin 23 | PA18 — General purpose I/O / SERCOM1 / TC |
| Pin 24 | PA19 — General purpose I/O / SERCOM1 / TC |
| Pin 25 | PA20 — General purpose I/O / SERCOM3 / TC |
| Pin 26 | PA21 — General purpose I/O / SERCOM3 / TC |
| Pin 27 | PA22 — General purpose I/O / SERCOM3 / TC |
| Pin 28 | PA23 — General purpose I/O / SERCOM3 / TC |
| Pin 29 | PA24 — General purpose I/O / SERCOM3 / USB D- |
| Pin 30 | PA25 — General purpose I/O / SERCOM3 / USB D+ |
| Pin 31 | RESETn — Reset input, active low |
| Pin 32 | VDD — Core/MCU supply voltage |
Typical Applications
ATSAMD20E18A-MU is suitable for 6 applications: Smart Home Sensor Hub, Industrial Controller Board, USB HID / CDC Device, Battery-Powered Metering Device, Capacitive Touch HMI Front Panel, Consumer Wearable / Fitness Tracker.
Smart Home Sensor Hub
The ATSAMD20E18A-MU fits smart-home sensor hubs because its 48 MHz Cortex-M0+ core, 256 KB Flash and 32 KB SRAM can host a Zigbee/Thread/BLE bridge firmware plus multiple environmental sensors. The integrated Peripheral Touch Controller (PTC) and SleepWalking peripheral event system allow buttons or capacitive pads to wake the MCU only when touched, drawing microamp-level standby current on a 1.62-3.63 V single Li-Ion rail. Placing the MCU behind a 3.3 V LDO with a 0.1 uF + 4.7 uF decoupling network prevents regulator noise from coupling into the ADC sampling window during periodic wake-and-measure cycles.
Recommended
Industrial Controller Board
For Industrial-control PLC-style I/O modules the ATSAMD20E18A-MU's industrial -40 C to +85 C rating and 48 MHz CPU are well matched to 24V-tolerant signal conditioning fronts and digital I/O multiplexing. The SERCOM modules map to EIA-485 transceivers, isolated SPI ADC front-ends, and I2C sensor ladders, while the 12-bit ADC captures analog backplane voltages. The 32-VQFN exposed pad is soldered to the ground pour to dissipate heat from GPIO switching losses in modules that toggle solenoids or relay coils at higher duty cycles.
Recommended
USB HID / CDC Device
The ATSAMD20E18A-MU integrates a full-speed USB 2.0 device controller, so it can implement HID, CDC or vendor-class USB peripherals (keyboards, sensors, custom instruments) without an external bridge IC. The SAM D20 USB core shares the on-chip PLL and requires a 32.768 kHz crystal to meet Suspend/Resume timing per USB 2.0 specification; pair with the on-chip SERCOM UART when implementing CDC-ACM bridge firmware. A common board-level pitfall is bypassing the USB DP pull-up resistor via a GPIO - leave D+ pull-up 1.5 kOhm to the device-only VBUS presence pin.
Recommended
Battery-Powered Metering Device
Battery-powered metering devices such as gas, water, or heat meters benefit from the ATSAMD20E18A-MU's SleepWalking peripheral event system and microamp-level standby current. The MCU stays in a deep-sleep state until the integrated peripheral touch controller, RTC, or external interrupt requests service, then wakes within a few cycles at 48 MHz to log the event into the 32 KB SRAM buffer. The 1.62-3.63 V supply range covers a single 1.5 V AA cell or a 3.6 V Li-SOCl2 primary cell, supporting meter life of a decade or more.
Recommended
Capacitive Touch HMI Front Panel
The on-chip Peripheral Touch Controller (PTC) supports up to 256 buttons, wheels, and sliders without an external touch IC, making the ATSAMD20E18A-MU a strong fit for HMI front panels on appliances, white goods, and small industrial displays. Its driven shield can extend touch detection through 3 mm of plastic, and the PTC uses DMA so the Cortex-M0+ core can stay in Idle when the user is not interacting with the panel. Five 5 mm pads at 5 mm pitch are typical of a four-segment slider interface on a glass front panel.
Recommended
Consumer Wearable / Fitness Tracker
Wearable fitness bands and consumer wearables favor the ATSAMD20E18A-MU for its 256 KB Flash footprint (large enough for BLE stack hosting via an external radio co-processor), 32 KB SRAM, and 3x3 mm board-level footprint when paired with a 4-layer flex PCB. The integrated SleepWalking peripheral event system and microamp-level standby current extend coin-cell life, while the integrated RTC and 32 kHz crystal domain keep wall-clock time during shipping and storage. Pair the MCU with an LIS2DH accelerometer and a BLE radio over SPI to form a typical step-counter reference design.
Recommended
Recommended Products Summary
Engineering reference data for ATSAMD20E18A-MU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAMD20E18A-MUT | ATSAMD20E18A-MNT | ATSAMD20E16B-MU | ATSAMD20E17A-AN | ATSAMD20E15B-MU |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 32-VQFN (5x5 mm) | 32-VQFN (5x5 mm) - same | 32-VQFN (5x5 mm) - same | 32-VQFN (5x5 mm) - same | 32-VQFN (5x5 mm) - same | 32-VQFN (5x5 mm) - same |
| Core / CPU | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz | ARM Cortex-M0+ @ 48 MHz |
| Flash | 256 KB | 256 KB | 256 KB | 64 KB | 128 KB | 32 KB |
| SRAM | 32 KB | 32 KB | 32 KB | 8 KB | 16 KB | 4 KB |
| Supply 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 |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +105 C | -40 C to +85 C | -40 C to +105 C | -40 C to +85 C |
| Peripheral Touch Controller (PTC) | Yes | Yes | Yes | Yes | Yes | Yes |
| 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 |
| Approx. Unit Price (1 pcs, as of 2026-09-21) | $4.40 | $4.40 | $4.55 | $3.20 | $3.80 | $2.95 |
Key Differentiators
- Largest Flash density in the SAM D20E 32VQFN family (vs ATSAMD20E15B-MU (32 KB Flash))
- Highest SRAM in the 32VQFN SAM D20 family (vs ATSAMD20E16B-MU (8 KB SRAM))
- Better price-to-memory ratio than -MNT variant for industrial temperatures (vs ATSAMD20E18A-MNT)
Design Notes
Estimated: with the 32-VQFN exposed pad soldered to a 1 oz copper pour of approximately 1 in2, junction-to-ambient thermal resistance is in the 30-40 C/W range. For USB workloads where I/O toggling increases dynamic power, verify junction temperature inside a sealed enclosure. Bond multiple thermal vias under the exposed pad to a low-impedance inner ground plane to keep Tj within the 85 C / 105 C industrial limit at the worst-case ambient.
Place the ATSAMD20E18A-MU 32-VQFN decoupling network as close to the VDD/VDDIO pins as possible. Use a 0.1 uF X7R ceramic in parallel with a 4.7 uF bulk ceramic, and provide a separate 10 nF for high-speed SERCOM and ADC rails. For USB data lines D+/D-, keep the 90-ohm differential pair length-matched within 150 mil and route away from the switching converter to maintain signal-integrity margins per the USB 2.0 FS specification.
Do not skip the 32.768 kHz external crystal on USB designs - the SAM D20 USB Suspend/Resume state machine relies on it. Also, when switching from a 32-pin SAM D20 part to a 48-pin one, the SERCOM pin map shifts between PAD[0]/PAD[1] and the alternate functions, so firmware that hard-codes pin multiplexing must be re-validated. Finally, ensure the boot loader fuse settings match the application entry vector: a misconfigured BOOTPROT can brick the device after a debug-session disconnect.
Compliance Information
RoHS and lead-free per Microchip product page. AEC-Q100 not applicable - this part is not qualified to automotive standards; Microchip SAMD20E automotive-grade counterparts exist in the SAM DA1 family, not the MU suffix.
