I decided to make my own ATmega32u4-based microcontroller board for several reasons. I wanted to have a general design based on this microcontroller which I can adapt in other PCB designs that need a microcontroller. I also wanted to practice SMD soldering, PCB design in general, and I needed some new microcontrollers so this was kind of a win-win situation.

I added an interactive BOM so you can pick the parts more easily.

Parts Value and footprint

C5, C7, C10 - 100nF C_0603_1608Metric

C2, C6 - 10uF CP_EIA-3528-12_Kemet-T

C4, C11 - 1uF C_0603_1608Metric

C8, C9 - 15pF* C_0603_1608Metric

R2, R3 - 22R R_0402_1005Metric

R4, R7 - 10k R_0603_1608Metric

R5, R6 - 330R R_0603_1608Metric

R1 - 1k5 R_0603_1608Metric

D1, D2, D3 - LED LED_0603_1608Metric

U1 - ATmega32U4-AU TQFP-44_10x10mm_P0.8mm

Y1 - Crystal Crystal_SMD_5032-2Pin_5.0x3.2mm

F1 - Polyfuse Fuse_1812_4532Metric

SW1 - SW_Push SW_SPST_PTS645

FB1 - 100R L_0805_2012Metric

J0 - USB_B_Micro USB_Micro-B_Amphenol_10103594-0001LF_Horizontal

Notice:

• C8 and C9 depend on the load capacitance of the crystal! You might have to use different value than mine.
• The open side of the LEDs' courtyard is the positive (VCC/anode) side. See: interactive BOM