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README

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ATSAMD21G18A-MF

Microchip Tech · Pre-ordered MCUs · QFN-48-EP(7x7)

ATSAMD21G18A-MF from Microchip Tech, in a QFN-48-EP(7x7). Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 PA00 bidirectional GPIO on VDDANA supply with EXTINT[0], SERCOM1 PAD[0] and TCC2 WO[0]; also XIN32 for the 32kHz crystal oscillator.
2 PA01 bidirectional GPIO on VDDANA supply with EXTINT[1], SERCOM1 PAD[1] and TCC2 WO[1]; also XOUT32 for the 32kHz crystal oscillator.
3 PA02 bidirectional GPIO on VDDANA supply with EXTINT[2], ADC AIN[0], PTC Y[0] and DAC VOUT.
4 PA03 bidirectional GPIO on VDDANA supply with EXTINT[3], ADC/DAC VREFA, ADC AIN[1] and PTC Y[1].
5 GNDANA power_in Analog ground, supply return for the VDDANA domain.
6 VDDANA power_in Analog supply input powering the analog I/O pins.
7 PB08 bidirectional GPIO on VDDANA supply with EXTINT[8], ADC AIN[2], PTC Y[14], SERCOM4 PAD[0] and TC4 WO[0].
8 PB09 bidirectional GPIO on VDDANA supply with EXTINT[9], ADC AIN[3], PTC Y[15], SERCOM4 PAD[1] and TC4 WO[1].
9 PA04 bidirectional GPIO on VDDANA supply with EXTINT[4], ADC/VREFB, ADC AIN[4], AC AIN[0], PTC Y[2] and SERCOM0 PAD[0].
10 PA05 bidirectional GPIO on VDDANA supply with EXTINT[5], ADC AIN[5], AC AIN[1], PTC Y[3] and SERCOM0 PAD[1].
11 PA06 bidirectional GPIO on VDDANA supply with EXTINT[6], ADC AIN[6], AC AIN[2], PTC Y[4] and SERCOM0 PAD[2].
12 PA07 bidirectional GPIO on VDDANA supply with EXTINT[7], ADC AIN[7], AC AIN[3], PTC Y[5], SERCOM0 PAD[3] and I2S SD[0].
13 PA08 bidirectional GPIO on VDDIO supply with NMI, ADC AIN[16], PTC X[0], SERCOM0/SERCOM2 PAD[0] and I2S SD[1].
14 PA09 bidirectional GPIO on VDDIO supply with EXTINT[9], ADC AIN[17], PTC X[1], SERCOM0/SERCOM2 PAD[1] and I2S MCK[0].
15 PA10 bidirectional GPIO on VDDIO supply with EXTINT[10], ADC AIN[18], PTC X[2], SERCOM0/SERCOM2 PAD[2], I2S SCK[0] and GCLK_IO[4].
16 PA11 bidirectional GPIO on VDDIO supply with EXTINT[11], ADC AIN[19], PTC X[3], SERCOM0/SERCOM2 PAD[3], I2S FS[0] and GCLK_IO[5].
17 VDDIO power_in Digital I/O supply input for the adjacent I/O pins.
18 GND power_in Ground.
19 PB10 bidirectional GPIO on VDDIO supply with EXTINT[10], SERCOM4 PAD[2], TC5 WO[0], TCC0 WO[4], I2S MCK[1] and GCLK_IO[4].
20 PB11 bidirectional GPIO on VDDIO supply with EXTINT[11], SERCOM4 PAD[3], TC5 WO[1], TCC0 WO[5], I2S SCK[1] and GCLK_IO[5].
21 PA12 bidirectional GPIO on VDDIO supply with EXTINT[12], SERCOM2 PAD[0]/SERCOM4 PAD[0], TCC2 WO[0], TCC0 WO[6] and AC CMP[0].
22 PA13 bidirectional GPIO on VDDIO supply with EXTINT[13], SERCOM2 PAD[1]/SERCOM4 PAD[1], TCC2 WO[1], TCC0 WO[7] and AC CMP[1].
23 PA14 bidirectional GPIO on VDDIO supply with EXTINT[14], SERCOM2/SERCOM4 PAD[2], TC3 WO[0], TCC0 WO[4] and GCLK_IO[0]; also XIN for the crystal oscillator.
24 PA15 bidirectional GPIO on VDDIO supply with EXTINT[15], SERCOM2/SERCOM4 PAD[3], TC3 WO[1], TCC0 WO[5] and GCLK_IO[1]; also XOUT for the crystal oscillator.
25 PA16 bidirectional GPIO on VDDIO supply with EXTINT[0], PTC X[4], SERCOM1/SERCOM3 PAD[0], TCC2 WO[0], TCC0 WO[6] and GCLK_IO[2].
26 PA17 bidirectional GPIO on VDDIO supply with EXTINT[1], PTC X[5], SERCOM1/SERCOM3 PAD[1], TCC2 WO[1], TCC0 WO[7] and GCLK_IO[3].
27 PA18 bidirectional GPIO on VDDIO supply with EXTINT[2], PTC X[6], SERCOM1/SERCOM3 PAD[2], TC3 WO[0], TCC0 WO[2] and AC CMP[0].
28 PA19 bidirectional GPIO on VDDIO supply with EXTINT[3], PTC X[7], SERCOM1/SERCOM3 PAD[3], TC3 WO[1], TCC0 WO[3], I2S SD[0] and AC CMP[1].
29 PA20 bidirectional GPIO on VDDIO supply with EXTINT[4], PTC X[8], SERCOM5/SERCOM3 PAD[2], TC7 WO[0], TCC0 WO[6], I2S SCK[0] and GCLK_IO[4].
30 PA21 bidirectional GPIO on VDDIO supply with EXTINT[5], PTC X[9], SERCOM5/SERCOM3 PAD[3], TC7 WO[1], TCC0 WO[7], I2S FS[0] and GCLK_IO[5].
31 PA22 bidirectional GPIO on VDDIO supply with EXTINT[6], PTC X[10], SERCOM3/SERCOM5 PAD[0], TC4 WO[0], TCC0 WO[4] and GCLK_IO[6].
32 PA23 bidirectional GPIO on VDDIO supply with EXTINT[7], PTC X[11], SERCOM3/SERCOM5 PAD[1], TC4 WO[1], TCC0 WO[5], USB SOF 1kHz and GCLK_IO[7].
33 PA24 bidirectional GPIO on VDDIO supply with EXTINT[12], SERCOM3/SERCOM5 PAD[2], TC5 WO[0], TCC1 WO[2] and USB DM; enable a pull-up if unconnected to avoid extra consumption (<1mA).
34 PA25 bidirectional GPIO on VDDIO supply with EXTINT[13], SERCOM3/SERCOM5 PAD[3], TC5 WO[1], TCC1 WO[3] and USB DP; enable a pull-up if unconnected to avoid extra consumption (<1mA).
35 GND power_in Ground.
36 VDDIO power_in Digital I/O supply input for the adjacent I/O pins.
37 PB22 bidirectional GPIO on VDDIO supply with EXTINT[6], SERCOM5 PAD[2], TC7 WO[0] and GCLK_IO[0].
38 PB23 bidirectional GPIO on VDDIO supply with EXTINT[7], SERCOM5 PAD[3], TC7 WO[1] and GCLK_IO[1].
39 PA27 bidirectional GPIO on VDDIO supply with EXTINT[15] and GCLK_IO[0].
40 RESET input External reset input, active low.
41 PA28 bidirectional GPIO on VDDIO supply with EXTINT[8] and GCLK_IO[0].
42 GND power_in Ground.
43 VDDCORE power_out Regulated output supply for the core, to be decoupled externally.
44 VDDIN power_in Input supply for the internal regulator and the adjacent I/O pins.
45 PA30 bidirectional GPIO on VDDIO supply with EXTINT[10], SERCOM1 PAD[2], TCC1 WO[0] and GCLK_IO[0]; also SWCLK for serial wire debug.
46 PA31 bidirectional GPIO on VDDIO supply with EXTINT[11], SERCOM1 PAD[3] and TCC1 WO[1]; also SWDIO, active only when a debugger is present.
47 PB02 bidirectional GPIO on VDDANA supply with EXTINT[2], ADC AIN[10], PTC Y[8], SERCOM5 PAD[0] and TC6 WO[0].
48 PB03 bidirectional GPIO on VDDANA supply with EXTINT[3], ADC AIN[11], PTC Y[9], SERCOM5 PAD[1] and TC6 WO[1].
49 EP passive Exposed pad (from the footprint; not named in the datasheet pin table).

Key specifications

Parameter Value
Manufacturer Microchip Tech
Package QFN-48-EP(7x7)
Category Embedded Processors & Controllers
Pins 49

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter Symbol Min Typ Max Unit Conditions Page
Operating voltage (SAM D21) VDD 1.62 3.63 V SAM D21 2
VDDIO supply voltage VDDIO 1.62 3.63 V 35
VDDIN supply voltage VDDIN 1.62 3.63 V 35
VDDANA supply voltage VDDANA 1.62 3.63 V 35
Operating temperature -40 125 °C F = -40 - 125°C Matte Sn Plating 16
VDDCORE regulated voltage VDDCORE 1.2 V Internal regulated voltage output 35
CPU maximum frequency Fmax 48 MHz Cortex-M0+ 1

Materials and finish

As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).

Part Material Colour / plating Datasheet says Page
contacts tin including indium tin oxide (ITO) sensor grids. The PTC requires one pin per X-line and one pin per Y-line. In the self-capacitance mode, the PTC requires only one pin (Y-line) for each touch sensor. 859

CAD (KiCad official)

  • Symbol: ATSAMD21G18A-MF
  • Footprint: Package_DFN_QFN:QFN-48-1EP_7x7mm_P0.5mm_EP5.15x5.15mm
  • 3D model: QFN-48-EP(7x7) (KiCad packages3D, STEP)
  • 3D model files: atsamd21g18a-mf-etched.step / atsamd21g18a-mf-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); atsamd21g18a-mf.step / atsamd21g18a-mf.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Microchip Tech datasheet (1148 pp, sha256 18ca1ccab5aa330f, retrieved 2026-10-23, tier: manufacturer)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF