Design rules¶

PCB facturing¶

Aisler Specs
Calc
Description
Power

Base material	FR4 TG 140°
	Technolam UV-Block FR-4-86 681
PCB Thickness	1.6mm (0.063inches)
Base copper thickness	18µm
Min. processed copper thickness	35µm

A 15cm trace with minimum width (0.15mm) has an resistance of ca. 0,5 Ohm. A shortcut would limit to 6 Amps.
A 2cm trace has an resistance of 0,07Ohm; 42 Amps.

15cm	0.15mm	0.5 Ohm
15cm	0.2mm	0.37 Ohm
15cm	0.25mm	0.29 Ohm	0,5A@Delta-10°	1,0A@Delta-30°
15cm	0.5mm	0.15 Ohm	1,0A@Delta-10°
15cm	1mm	0.07 Ohm	2,2A@Delta-10°

An QFN pad has an width of 0,25mm;

Traces¶

min. drill diameter: >=0,3mm
min. trace width: 0,150mm
pad diameter DuKo: 0,6mm (spec. 0,7mm?) !!
hole to hole: 0,35mm (not specificated. Via was missing. Wert empirisch. Does not happen when following other design rules)
Distance to cuts 0,35mm (cut-through to easily by grinding)

• Power: 0,2 distance; 0,2 width
• Powerline (240V): 1,5 distance; 2,5 width (CANSwitch)

2,5mm: ca. 1.5A bei 10°C rise

Text varnish¶

Lack:
Gut, fuer längeren Text:
0,7x0,7; Staerke 0,1mm (NUC64Debug V0.2.x)
(zu klein fuer Schrift in Copper)

Zu klein:
0,4x0,4; Staerke: 0,05 (CAN/IO)

Geht noch, nicht kleiner:
0,6x0,6; Staerke: 0,05 (CANDisplay::Eval; Miniminutnik)

Geht noch, eher nicht kleiner, manche Labels nicht mehr eindeutig:
0,55x0,55; Staerke: 0,15 (CAN/IO v0.6.x, einzelne Referenzen nur erratbar)

Text copper¶

Copper:

Gut unverzinnt:
0,6x0,6; Starke 0,08mm

schlecht verzinnt:
0,7x0,7; Staerke 0,1mm (NUC64Debug)

nearly ok:
0,75x0,75; Staerke 0,15mm (Candisplay Eval)

Still dots not ok:
0,8x0,8; Staerke 0,2mm (CANIO 0.6.x)

next test:
0,85x0,85; Staerke 0,25mm (EEPROM)

Standard LEDs; 2V @ 3V¶

120 Ohm: very bright
240: bright, ok for blinking, still to bright for permanent on
480: should be the usual case
1k Ohm: very dark. eg. ok for power LED