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硬體部分
1. PC板之堆疊順序
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NO.
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6 Layers
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8 Layers
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10 Layers
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12 Layers
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1
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Middle speed
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Middle speed
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Middle speed
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Middle speed
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2
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CLK & High speed
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GND
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GND
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GND
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3
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GND
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CLK & High speed
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CLK & High speed
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CLK & High speed
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4
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Vcc
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GND
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CLK & High speed
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CLK & High speed
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5
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Others
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Vcc
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GND
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CLK & High speed
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6
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CLK & High speed
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CLK & High speed
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Vcc
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GND
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7
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GND
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Others
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Vcc
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8
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Others
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CLK & High speed
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Others
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9
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GND
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CLK & High speed
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10
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Middle speed
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CLK & High speed
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11
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GND
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12
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Middle speed
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Remark: 1. CLK & High speed: 30MHz以上.
2. Middle speed: 10—30MHz.
3. Others: 10MHz以下.
2. PC板應(yīng)保持完整性, 以正方形或長(zhǎng)方形為最佳, 避免有缺口或不規(guī)則.
3. PC應(yīng)以一塊為最佳, 避免多塊組合.
4. PC板之板邊應(yīng)有3mm以上之trace來(lái)圍繞,Ground trace以10-15mm的距離,並以random方式加through hole.
5. PC板之板邊應(yīng)有3mm以上之trace來(lái)圍繞,並加SMD Finger與PC板下之金屬表面接觸.
1. ALL signals應(yīng)與板邊GND Trace及固定孔之距離為2mm.
2. Mother board上,至少要有7個(gè)以上之固定孔,並力求平衡,不要集中在一處.而其他區(qū)域則無(wú)螺絲孔可供下地,此螺絲孔應(yīng)靠近I/O connector及VGA IC, Clock generator, DC IN.
3. All PC板之固定孔,必須導(dǎo)通,不能將PAD除掉.
4. Glide Pad的PC板上之signal line務(wù)必包地.
5. 每一I/O Chip set,需要放置在I/O Port之最近位置.VGA port & TV port & S terminal port需放置在一起.
6. All I/O ports之GND plane要切割.
7. VGA chip & Clock Generator務(wù)必將GND給予切割.
8. ALL I/O ports之EMI components,分別以2mm之距離,靠近I/O connector位置.
9. ALL I/O connector之固定腳PAD,再加2mm.
10. 高速訊號(hào)線& Clock trace應(yīng)放至內(nèi)層,並靠近GND Plane.
11. Clock trace若無(wú)法包地,其Trace & Trace之spacing是Trace的兩倍.
12. Clock generator and Main chip set在placement時(shí)不可放在板邊,應(yīng)放置在中間.
13. 各chip set的信號(hào)線,其trace越短越好,clock trace須包地,頻率越高,trace越短.
14. 各chip set的信號(hào)線在走線時(shí),不可平行重疊在一起,須垂直走線.
15. LAN & MODEM Jack至Connector之trace,其附近之每一層,不宜走線,並且Connector之外5mm應(yīng)掏空.
16. Modem & LAN card, Combo card with Modem & LAN應(yīng)儘量靠近LAN & Modem Jack connector. Modem & LAN Cable應(yīng)走板邊,並避開(kāi)DC/DC components & High Frequency components.
17. 若ESD可直接打入訊號(hào)點(diǎn),則應(yīng)予以絕緣包之或圍Ground Trace做保護(hù).
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