STPCI2GDYI STMicroelectronics, STPCI2GDYI Datasheet - Page 100

• Manufacturer Part Number: STPCI2GDYI
• Description: IC SYSTEM-ON-CHIP X86 516-PBGA
• Manufacturer: STMicroelectronics

Specifications of STPCI2GDYI

• Applications: Graphics Controller
• Core Processor: x86
• Controller Series: STPC® Atlas
• Interface: UART
• Number Of I /o: 16
• Voltage - Supply: 2.45 V ~ 2.7 V
• Operating Temperature: -40°C ~ 115°C
• Mounting Type: Surface Mount
• Package / Case: 516-PBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Program Memory Type: -
• Ram Size: -
• Lead Free Status / Rohs Status: Compliant

STPC® ATLAS
When considering thermal dissipation, one of the
most important parts of the layout is the
connection between the ground balls and the
ground layer.
Considering only the central matrix of 36 thermal
balls and one via for each ball, the global thermal
resistance is 2.9°C/W. This can be easily
improved using four 12.5 mil wires to connect to
The use of a ground plane like in
even better.
100/108
Figure 6-32. Recommended 1-wire Power/Ground Pad Layout
Figure 6-33. Recommended 4-wire Ground Pad Layout
Figure 6-34
is
A 1-wire connection is shown in
use of a 8-mil wire results in a thermal resistance
of 105°C/W assuming copper is used (418 W/
m.°K). This high value is due to the thickness (34
µm) of the copper on the external side of the PCB.
the four vias around the ground pad link as in
Figure
global resistance for the 36 thermal balls of 0.5°C/
W.
Pad for ground ball (diameter = 25 mil)
Solder Mask (4 mil)
Connection Wire (width = 12.5 mil)
Via (diameter = 24 mil)
Hole to ground layer (diameter = 12 mil)
4 via pads for each ground ball
6-33. This gives a total of 49 vias and a
1 mil = 0.0254 mm
Figure
5-1. The