BGA - Ball Grid Array

BGAs (Ball Grid Arrays) are SMD components with connections on the bottom of the component. Each pin is provided with a solder ball. All connections are distributed in a uniform surface grid or matrix on the component. Common grids are nowadays: 1.27 mm - 1.00 mm - 0.80 mm - 0.50 mm.

With several hundred component connections, the number of „routable" pins is limited per layer. The inner pins of the BGA can only be connected through a via and routed to another layer > DogBone technology.

If the pitch is even smaller, or if traces between the solder pads are necessary, the via-in-pad technology is recommended: The vias are placed directly into the solder pads of the BGA.

Manufacturer's instructions must be followed carefully. These define the elementary connection distances, solder ball diameters and the housing geometries. Other technical details such as technology of the vias or trace -width and -spacing will be specified by the designer. For possible parameters check the following tables.

BGA: Design proposal

The values given are design proposals, values of component data sheets are always preferable.

Pitch	Ø BGA-Pad*	Ø Via-Pad / Via-Drill	Ø Via-Pad**/ Via-Drill	Track-width / -space	Track-width / -space
		Dog-Bone	Via-in-Pad
1.27mm	550µm	550µm/300µm	-	150µm/285µm	150µm/140µm
1.00mm	500µm	500µm/200µm	-	150µm/175µm	100µm/100µm
0.80mm	350µm	450µm/150µm	400µm/200µm	150µm/100µm	70µm/70µm
0.50mm	250µm	250µm/100µm	300µm/100µm	70µm/90µm	-
0.40mm	see below	see below	see below	see below	see below

*plus 50µm circumferential solder-stop clearance
**plus 50µm circumferential solder-stop clearance, please order as IPC 4761 Type VII: Filled & Capped Vias

BGA Dogbone - Detail

Outer layers

	Pitch =	1.27mm	1.00mm	0.80mm	0.50mm
a	Ø BGA Pad (solder pad)	550µm	500µm	350µm	250µm
b	Solder-stop (SS) clearance, circumferential	75µm	75µm	75µm	75µm
c	Ø Solder-stop clearance	700µm	650µm	500µm	400µm
d	Stringer length (approx.)	348µm	207µm	165µm	103µm
e	Ø Via Pad	550µm	500µm	450µm	250µm
f	Ø Via Pad drill (final)	300µm	200µm	150µm	100µm
g	Via Pad <> BGA Pad	348µm	207µm	165µm	103µm
h	Stringer width	250µm	250µm	200µm	150µm
i	SS clearance <> SS clearance	570µm	350µm	300µm	100µm
j	Via Pad <> Via Pad	720µm	500µm	350µm	250µm

Inner layers

Fan-Out with 1 track

	Pitch =	1.27mm	1.00mm	0.80mm	0.50mm
e	Ø Via Pad	670µm	550µm	425µm	260µm
b	Ø Via Pad Drill	300µm	250µm	150µm	100µm
k	Track Width	200µm	150µm	125µm	80µm
l	Track Space	200µm	150µm	125µm	80µm

Inner layers

Fan-Out with 2 tracks

	Pitch =	1.27mm	1.00mm	0.80mm	0.50mm
e	Ø Via Pad	620µm	485µm	300µm	-
b	Ø Via Pad Drill	300µm	250µm	150µm	-
k	Track Width	125µm	100µm	100µm	-
l	Track Space	125µm	100µm	100µm	-

Inner layers

Fan-Out with 3 tracks

	Pitch =	1.27mm	1.00mm	0.80mm	0.50mm
e	Ø Via Pad	550µm	460µm	275µm	-
b	Ø Via Pad Drill	250µm	200µm	100µm	-
k	Track Width	100µm	75µm	75µm	-
l	Track Space	100µm	75µm	75µm	-

BGA 0.4mm Pitch

The PCB design for BGA with 0.4mm pitch is special production and requires the use of HDI-Technology and Via-in-Pad. Please always consult our technical department.