Mediatek MT7620是一款IEEE802.11n片上路由芯片,其内部集成了一个802.11n MAC/基带/2.4GHz射频模块,一个主频为580MHz MIPS 24K的处理器,一个5端口百兆以太网交换机,二个RGMII接口。可以说,MT7620包含了实现无线路由器,无线AP所需要的全部功能模块,这与Atheros 芯片的定位极其相似。MT7620的高性能处理器可以轻松应对各种高级应用,例如路由,安全,VoIP等。
实物产品
1.原理图设计开篇: RF基带部分包括LC滤波和巴伦,基本上可以参考设计用料,MTK并不挑高频电容ESR和电感Q值,村田品牌并不是必选,但在高通芯片上的选型就显得尤为重要,在后续高通方案上会讲到。然后要注意电源的旁路小电容的放置,像PLL,RF_VX_LDO,RF_PA_V33在这些供电脚的周围有很多滤波电容,在画板的时候一定要尽量把电容靠管脚放,滤波效果更好,让系统和无线指标更趋于理想。
关于使用32M SPI Flash的设置,在原理图的Boot Up Strapping部分有说明,只要配置CHIP_MODE为0011就改变SPI寻址位,这样即可实现32M容量配置。
2.PCB板图设计篇:Layout需要注意点就在RF走线,掌握2点,一是先计算好50欧姆的走线宽度和间距,射频线不走直角,尽可能拉弧线;二是射频线周围3CM不要放置磁性元件,也要远离电源走线。DDR1内存的走线原则就是数据和时钟线追求等长,USB线满足90欧姆差分阻抗,网口线满足100欧姆的差分阻抗即可。
3.IQ校准射频篇:利用SDK产测固件在IQ仪器上运行后的测试数据
1. IQ_CAL_TX_XTAL
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Cal XTAL Offset 0.626 ppm (5.0 ~ -5.0)
2. IQ_CAL_TX_OUTPUT 2G
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Tx0 Ch 1 13.636 dBm (15.0 ~ 13.5)
Tx0 Ch 6 13.670 dBm (15.0 ~ 13.5)
Tx0 Ch 11 13.620 dBm (15.0 ~ 13.5)
Tx1 Ch 1 14.227 dBm (15.0 ~ 13.5)
Tx1 Ch 6 13.878 dBm (15.0 ~ 13.5)
Tx1 Ch 11 14.548 dBm (15.0 ~ 13.5)
3. IQ_VERIFY_TX 2412 11M TX0
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Freq Err 0.671 ppm (20.0 ~ -20.0)
EVM -27.746 dB (-10.0 ~ -100.0)
Power 17.214 dBm (19.0 ~ 14.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
4. IQ_VERIFY_TX 2437 11M TX0
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Freq Err 0.811 ppm (20.0 ~ -20.0)
EVM -27.556 dB (-10.0 ~ -100.0)
Power 17.275 dBm (19.0 ~ 14.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
5. IQ_VERIFY_TX 2462 11M TX0
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Freq Err 0.966 ppm (20.0 ~ -20.0)
EVM -27.071 dB (-10.0 ~ -100.0)
Power 17.270 dBm (19.0 ~ 14.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
6. IQ_VERIFY_TX 2412 54M TX0
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Freq Err 0.875 ppm (20.0 ~ -20.0)
EVM -32.844 dB (-25.0 ~ -100.0)
Power 13.363 dBm (15.5 ~ 12.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
7. IQ_VERIFY_TX 2437 54M TX0
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Freq Err 0.712 ppm (20.0 ~ -20.0)
EVM -32.058 dB (-25.0 ~ -100.0)
Power 13.488 dBm (15.5 ~ 12.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
8. IQ_VERIFY_TX 2462 54M TX0
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Freq Err 0.755 ppm (20.0 ~ -20.0)
EVM -32.747 dB (-25.0 ~ -100.0)
Power 13.366 dBm (15.5 ~ 12.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
9. IQ_VERIFY_TX 2412 HT20_MCS7 TX0
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Freq Err 0.565 ppm (20.0 ~ -20.0)
EVM -30.877 dB (-28.0 ~ -100.0)
Power 12.532 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
10. IQ_VERIFY_TX 2437 HT20_MCS7 TX0
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Freq Err 0.585 ppm (20.0 ~ -20.0)
EVM -32.651 dB (-28.0 ~ -100.0)
Power 12.606 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
11. IQ_VERIFY_TX 2462 HT20_MCS7 TX0
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Freq Err 0.662 ppm (20.0 ~ -20.0)
EVM -33.597 dB (-28.0 ~ -100.0)
Power 12.506 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
12. IQ_VERIFY_TX 2422 HT40_MCS7 TX0
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Freq Err 0.659 ppm (20.0 ~ -20.0)
EVM -32.718 dB (-28.0 ~ -100.0)
Power 12.095 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
13. IQ_VERIFY_TX 2437 HT40_MCS7 TX0
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Freq Err 0.681 ppm (20.0 ~ -20.0)
EVM -31.538 dB (-28.0 ~ -100.0)
Power 12.295 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
14. IQ_VERIFY_TX 2462 HT40_MCS7 TX0
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Freq Err 0.768 ppm (20.0 ~ -20.0)
EVM -30.641 dB (-28.0 ~ -100.0)
Power 12.120 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
15. IQ_VERIFY_TX 2412 11M TX1
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Freq Err 0.485 ppm (20.0 ~ -20.0)
EVM -28.068 dB (-10.0 ~ -100.0)
Power 17.925 dBm (19.0 ~ 14.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
16. IQ_VERIFY_TX 2437 11M TX1
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Freq Err 0.536 ppm (20.0 ~ -20.0)
EVM -27.816 dB (-10.0 ~ -100.0)
Power 17.520 dBm (19.0 ~ 14.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
17. IQ_VERIFY_TX 2462 11M TX1
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Freq Err 0.806 ppm (20.0 ~ -20.0)
EVM -28.023 dB (-10.0 ~ -100.0)
Power 18.137 dBm (19.0 ~ 14.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
18. IQ_VERIFY_TX 2412 54M TX1
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Freq Err 0.715 ppm (20.0 ~ -20.0)
EVM -28.632 dB (-25.0 ~ -100.0)
Power 13.893 dBm (15.5 ~ 12.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
19. IQ_VERIFY_TX 2437 54M TX1
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Freq Err 0.571 ppm (20.0 ~ -20.0)
EVM -28.093 dB (-25.0 ~ -100.0)
Power 13.562 dBm (15.5 ~ 12.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
20. IQ_VERIFY_TX 2462 54M TX1
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Freq Err 0.694 ppm (20.0 ~ -20.0)
EVM -29.135 dB (-25.0 ~ -100.0)
Power 14.186 dBm (15.5 ~ 12.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
21. IQ_VERIFY_TX 2412 HT20_MCS7 TX1
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Freq Err 0.457 ppm (20.0 ~ -20.0)
EVM -31.029 dB (-28.0 ~ -100.0)
Power 13.201 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
22. IQ_VERIFY_TX 2437 HT20_MCS7 TX1
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Freq Err 0.466 ppm (20.0 ~ -20.0)
EVM -30.709 dB (-28.0 ~ -100.0)
Power 12.793 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
23. IQ_VERIFY_TX 2462 HT20_MCS7 TX1
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Freq Err 0.610 ppm (20.0 ~ -20.0)
EVM -29.540 dB (-28.0 ~ -100.0)
Power 13.416 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
24. IQ_VERIFY_TX 2422 HT40_MCS7 TX1
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Freq Err 0.558 ppm (20.0 ~ -20.0)
EVM -32.506 dB (-28.0 ~ -100.0)
Power 12.506 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
25. IQ_VERIFY_TX 2437 HT40_MCS7 TX1
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Freq Err 0.605 ppm (20.0 ~ -20.0)
EVM -31.699 dB (-28.0 ~ -100.0)
Power 12.430 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
26. IQ_VERIFY_TX 2462 HT40_MCS7 TX1
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Freq Err 0.703 ppm (20.0 ~ -20.0)
EVM -30.851 dB (-28.0 ~ -100.0)
Power 13.074 dBm (15.5 ~ 11.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
27. IQ_VERIFY_TX 2462 HT40_MCS15
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Freq Err 1.129 ppm (20.0 ~ -20.0)
EVM -30.721 dB (-28.0 ~ -100.0)
Power Tx0 11.214 dBm (12.5 ~ 9.5)
Power Tx1 12.183 dBm (12.5 ~ 9.5)
Spec Mask 0.000 % (0.0 ~ 0.0)
28. IQ_SWEEP_RX_PER 2412 11M RX0
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Sensitivity: -88.0 dBm
29. IQ_SWEEP_RX_PER 2437 11M RX0
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Sensitivity: -88.0 dBm
30. IQ_SWEEP_RX_PER 2462 11M RX0
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Sensitivity: -89.0 dBm
31. IQ_SWEEP_RX_PER 2412 54M RX0
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Sensitivity: -74.0 dBm
32. IQ_SWEEP_RX_PER 2437 54M RX0
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Sensitivity: -73.0 dBm
33. IQ_SWEEP_RX_PER 2462 54M RX0
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Sensitivity: -75.0 dBm
34. IQ_SWEEP_RX_PER 2412 HT20_MCS7 RX0
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Sensitivity: -73.0 dBm
35. IQ_SWEEP_RX_PER 2437 HT20_MCS7 RX0
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Sensitivity: -72.0 dBm
36. IQ_SWEEP_RX_PER 2462 HT20_MCS7 RX0
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Sensitivity: -73.0 dBm
37. IQ_SWEEP_RX_PER 2422 HT40_MCS7 RX0
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Sensitivity: -69.0 dBm
38. IQ_SWEEP_RX_PER 2437 HT40_MCS7 RX0
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Sensitivity: -70.0 dBm
39. IQ_SWEEP_RX_PER 2462 HT40_MCS7 RX0
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Sensitivity: -68.0 dBm
40. IQ_SWEEP_RX_PER 2412 11M RX1
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Sensitivity: -88.0 dBm
41. IQ_SWEEP_RX_PER 2437 11M RX1
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Sensitivity: -86.0 dBm
42. IQ_SWEEP_RX_PER 2462 11M RX1
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Sensitivity: -88.0 dBm
43. IQ_SWEEP_RX_PER 2412 54M RX1
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Sensitivity: -74.0 dBm
44. IQ_SWEEP_RX_PER 2437 54M RX1
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Sensitivity: -73.0 dBm
45. IQ_SWEEP_RX_PER 2462 54M RX1
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Sensitivity: -74.0 dBm
46. IQ_SWEEP_RX_PER 2412 HT20_MCS7 RX1
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Sensitivity: -72.0 dBm
47. IQ_SWEEP_RX_PER 2437 HT20_MCS7 RX1
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Sensitivity: -72.0 dBm
48. IQ_SWEEP_RX_PER 2462 HT20_MCS7 RX1
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Sensitivity: -72.0 dBm
49. IQ_SWEEP_RX_PER 2422 HT40_MCS7 RX1
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Sensitivity: -68.0 dBm
50. IQ_SWEEP_RX_PER 2437 HT40_MCS7 RX1
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Sensitivity: -68.0 dBm
51. IQ_SWEEP_RX_PER 2462 HT40_MCS7 RX1
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Sensitivity: -68.0 dBm
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**** P A S S ****
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Total Test Time:00:08:03
4.实测吞吐量数据篇:开放的停车场环境内,搭配300M无线网卡陪测
5.分享下芯片丝印标记的差异
此方案的整套设计资料下载地址:https://download.csdn.net/download/zhangbao19890622/12589262