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README

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ATSAML21E18B-MUT

Microchip Tech · Global Sourcing Parts · QFN-32(5x5)

ATSAML21E18B-MUT from Microchip Tech, in a QFN-32(5x5). 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 Port A general-purpose I/O PA00, supplied from VSWOUT; alternate functions include EXTINT[0]/EXTWAKE[0], SERCOM1 PAD[0], TCC2 WO[0] and the XIN32 32 kHz oscillator input.
2 PA01 bidirectional Port A general-purpose I/O PA01, supplied from VSWOUT; alternate functions include EXTINT[1]/EXTWAKE[1], SERCOM1 PAD[1], TCC2 WO[1] and the XOUT32 32 kHz oscillator output.
3 PA02 bidirectional Port A I/O PA02 supplied from VDDANA with analog functions AIN[0], Y[0], VOUT[0] and OA_NEG[0] plus EXTINT[2]/EXTWAKE[2]; enabling an analog peripheral disables the digital function of the pin.
4 PA03 bidirectional Port A I/O PA03 supplied from VDDANA with analog functions VREFA, AIN[1] and Y[1] plus EXTINT[3]/EXTWAKE[3]; enabling an analog peripheral disables the digital function of the pin.
5 PA04 bidirectional Port A general-purpose I/O PA04 supplied from VDDANA; alternate functions include VREFB, AIN[4], AIN[0], OA_OUT[2], EXTINT[4]/EXTWAKE[4], SERCOM0 PAD[0] and TCC0 WO[0].
6 PA05 bidirectional Port A general-purpose I/O PA05 supplied from VDDANA; alternate functions include AIN[5], AIN[1], VOUT[1], OA_POS[2], EXTINT[5]/EXTWAKE[5], SERCOM0 PAD[1] and TCC0 WO[1].
7 PA06 bidirectional Port A general-purpose I/O PA06 supplied from VDDANA; alternate functions include AIN[6], AIN[2], Y[4], OA_POS[0], EXTINT[6]/EXTWAKE[6], SERCOM0 PAD[2] and TCC1 WO[0].
8 PA07 bidirectional Port A general-purpose I/O PA07 supplied from VDDANA; alternate functions include AIN[7], AIN[3], OA_OUT[0], EXTINT[7]/EXTWAKE[7], SERCOM0 PAD[3] and TCC1 WO[1].
9 VDDANA power_in Analog supply voltage of 1.6 V to 3.6 V, decoupled with 100 nF and 10 µF capacitors, with a ferrite bead recommended to keep digital noise out of the analog domain.
10 GND power_in Ground reference for the device.
11 PA08 bidirectional Port A general-purpose I/O PA08, a High Sink pin, supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include NMI, AIN[16], X[0], Y[6], SERCOM0/SERCOM2 PAD[0], TCC0 WO[0] and TCC1 WO[2].
12 PA09 bidirectional Port A general-purpose I/O PA09, a High Sink pin, supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[9], AIN[17], X[1], Y[7], SERCOM0/SERCOM2 PAD[1], TCC0 WO[1] and TCC1 WO[3].
13 PA10 bidirectional Port A general-purpose I/O PA10 supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[10], AIN[18], X[2], Y[8], SERCOM0/SERCOM2 PAD[2], TCC1 WO[0], TCC0 WO[2] and GCLK_IO[4].
14 PA11 bidirectional Port A general-purpose I/O PA11 supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[11], AIN[19], X[3], Y[9], SERCOM0/SERCOM2 PAD[3], TCC1 WO[1], TCC0 WO[3] and GCLK_IO[5].
15 PA14 bidirectional Port A general-purpose I/O PA14 supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[14], SERCOM2/SERCOM4 PAD[2], TC4 WO[0], TCC0 WO[4], GCLK_IO[0] and the XIN oscillator input.
16 PA15 bidirectional Port A general-purpose I/O PA15 supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[15], SERCOM2/SERCOM4 PAD[3], TC4 WO[1], TCC0 WO[5], GCLK_IO[1] and the XOUT oscillator output.
17 PA16 bidirectional Port A general-purpose I/O PA16, a High Sink pin, supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[0], X[4], SERCOM1/SERCOM3 PAD[0], TCC2 WO[0], TCC0 WO[6], GCLK_IO[2] and CCL0 IN[0] and supports SERCOM I2C.
18 PA17 bidirectional Port A general-purpose I/O PA17, a High Sink pin, supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[1], X[5], SERCOM1/SERCOM3 PAD[1], TCC2 WO[1], TCC0 WO[7], GCLK_IO[3] and CCL0 IN[1] and supports SERCOM I2C.
19 PA18 bidirectional Port A general-purpose I/O PA18 supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[2], X[6], SERCOM1/SERCOM3 PAD[2], TC4 WO[0], TCC0 WO[2], AC/CMP[0] and CCL0 IN[2].
20 PA19 bidirectional Port A general-purpose I/O PA19 supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[3], X[7], SERCOM1/SERCOM3 PAD[3], TC4 WO[1], TCC0 WO[3], AC/CMP[1] and CCL0 OUT.
21 PA22 bidirectional Port A general-purpose I/O PA22, a High Sink pin, supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[6], X[10], SERCOM3/SERCOM5 PAD[0], TC0 WO[0], TCC0 WO[4], GCLK_IO[6] and CCL2 IN[0] and supports SERCOM I2C.
22 PA23 bidirectional Port A general-purpose I/O PA23, a High Sink pin, supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[7], X[11], SERCOM3/SERCOM5 PAD[1], TC0 WO[1], TCC0 WO[5], USB SOF 1 kHz, GCLK_IO[7] and CCL2 IN[1] and supports SERCOM I2C.
23 PA24 bidirectional Port A general-purpose I/O PA24, supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[12], SERCOM3/SERCOM5 PAD[2], TC1 WO[0], TCC1 WO[2], USB DM and CCL2 IN[2]; its pull resistance is 50-150 kΩ.
24 PA25 bidirectional Port A general-purpose I/O PA25, supplied from VDDIO (which on SAM L21E is supplied through VDDANA); alternate functions include EXTINT[13], SERCOM3/SERCOM5 PAD[3], TC1 WO[1], TCC1 WO[3], USB DP and CCL2 OUT; its pull resistance is 50-150 kΩ.
25 PA27 bidirectional Port A general-purpose I/O PA27, a High Sink pin, supplied from VDDIN with alternate functions EXTINT[15] and GCLK_IO[0].
26 RESET input Active-low external reset input with an internal pull-up; the low-level threshold is below 0.36×VDDIO at 2.7-3.6 V and below 0.33×VDDIO at 1.6-2.0 V, and a 100 nF filter capacitor and 330 Ω series resistor are recommended.
27 VSW power_out On-chip switching regulator output that must connect to VDDCORE through a 10 µH inductor with saturation current above 150 mA and DCR below 1 Ω in switching mode, and is not connected in linear mode.
28 GND power_in Ground reference for the device.
29 VDDCORE power_in Core supply pin at 0.9 V to 1.2 V typical, decoupled with 100 nF and 1 µF; in linear regulator mode it is the core supply output for external decoupling, and in switched mode it is the core supply input connected to VSW via inductor.
30 VDDIN power_in Digital supply voltage of 1.6 V to 3.6 V, decoupled with 100 nF and 10 µF capacitors and a 10 µH filtering inductor.
31 PA30 bidirectional Port A general-purpose I/O PA30 supplied from VDDIN; alternate functions include EXTINT[10], SERCOM1/PAD[2], TCC1 WO[0], GCLK_IO[0] and CCL1 IN[0], and it is the CORTEX_M0P SWCLK serial wire clock pin.
32 PA31 bidirectional Port A general-purpose I/O PA31 supplied from VDDIN; alternate functions include EXTINT[11], SERCOM1/PAD[3], TCC1 WO[1] and CCL1 OUT, and it is the SWDIO serial wire data pin, which is activated only when a debugger is present.
33 EP passive Exposed pad (from the footprint; not named in the datasheet pin table).

Key specifications

Parameter Value
Manufacturer Microchip Tech
Package QFN-32(5x5)
Category Global Sourcing Parts
Pins 33

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 indium tin oxide (ITO) sensor grids. The PTC requires one pin per X-line and one pin per Y-line. In self-capacitance mode, the PTC requires only one pin (Y-line) for each touch sensor. 1034

CAD (KiCad official)

  • Symbol: ATSAML21E18B-MUT
  • Footprint: Package_DFN_QFN:QFN-32-1EP_5x5mm_P0.5mm_EP3.3x3.3mm
  • 3D model: QFN-32(5x5) (KiCad packages3D, STEP)
  • 3D model files: atsaml21e18b-mut-etched.step / atsaml21e18b-mut-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); atsaml21e18b-mut.step / atsaml21e18b-mut.glb are the bare package body.

Provenance

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

  • Datasheet: Microchip Tech datasheet (1158 pp, sha256 c7ade1efde79dc98, retrieved 2026-10-20, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-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