參數(shù)資料
型號(hào): STPCI2HDYC
英文描述: PERIPHERAL (MULTIFUNCTION) CONTROLLER
中文描述: 周邊(多功能)控制器
文件頁(yè)數(shù): 64/71頁(yè)
文件大?。?/td> 1071K
代理商: STPCI2HDYC
BOARD LAYOUT
64/69
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
Issue 2.4 - February 11, 2002
When considering thermal dissipation, the most
important - if not the most obvious - part of the
layout is the connection between the ground balls
and the ground layer.
A 1-wire connection is shown in
Figure 6-2
. The
use of 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.
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 improved by
using four 10 mil wires to connect to the four vias
around the ground pad link, as in
Figure 6-3
. This
gives a total of 49 vias and a global resistance for
the 36 thermal balls of 0.6°C/W.
The use of a ground plane, as shown in
Figure 6-
4
, is even better.
To avoid solder wicking over to the via pads during
soldering, it is important to have a solder mask of
4 mil around the pad (NSMD pad). This gives a
diameter of 33 mil for a 25 mil ground pad.
To obtain the optimum ground layout, place the
vias directly under the ball pads. In this case, no
local board distortion can be tolerated.
The thickness of the copper on PCB layers is
typically 34 μm for external layers and 17 μm for
internal layers. The resulting thermal dissipation is
not good, with areas of high temperature being
concentrated around the devices, falling off
quickly with increased distance.
Where possible, place a metal layer inside the
PCB. This will improve dramatically the spread of
heat and hence improve the thermal dissipation of
the board..
Figure 6-2. Recommended 1-wire Ground Pad Layout
Figure 6-3. Recommended 4-wire Ground Pad Layout
Solder Mask (4 mil)
Pad for ground ball (diameter = 25 mil)
Hole to ground layer (diameter = 12 mil)
Connection Wire (width = 10 mil)
Via (diameter = 24 mil)
345ml
1 mil = 0.0254 mm
4 via pads for each ground ball
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STPCI2HEYC 功能描述:微處理器 - MPU 133MHz x86 SoC RoHS:否 制造商:Atmel 處理器系列:SAMA5D31 核心:ARM Cortex A5 數(shù)據(jù)總線寬度:32 bit 最大時(shí)鐘頻率:536 MHz 程序存儲(chǔ)器大小:32 KB 數(shù)據(jù) RAM 大小:128 KB 接口類(lèi)型:CAN, Ethernet, LIN, SPI,TWI, UART, USB 工作電源電壓:1.8 V to 3.3 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:FBGA-324
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STPCINDUSTRIAL 制造商:STMICROELECTRONICS 制造商全稱(chēng):STMicroelectronics 功能描述:PC Compatible Embedded Microprocessor
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STP-CN05 功能描述:烙鐵 Cartridge Conical 0.5mm (0.02in) RoHS:否 制造商:Weller 產(chǎn)品:Soldering Stations 類(lèi)型:Digital, Iron, Stand, Cleaner 瓦特:50 W 最大溫度:+ 850 F 電纜類(lèi)型:US Cord Included