This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

[参考译文] LMX2820:在倍频器路径中使用即时校准

Guru**** 2392675 points
Other Parts Discussed in Thread: LMX2820

请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

https://e2e.ti.com/support/clock-timing-group/clock-and-timing/f/clock-timing-forum/1403323/lmx2820-using-instant-calibration-in-the-doubler-path

器件型号:LMX2820

工具与软件:

之前也有人提出过类似的问题: https://e2e.ti.com/support/clock-timing-group/clock-and-timing/f/clock-timing-forum/1028354/lmx2820-mux_out_doubler-issue-in-fast-vco-mode

没有 提供有用的答案。 所以我再问一次:

我们将频率设置为5.65GHz、并完成即时校准。 整个过程如下所示。 校准后、我们可以将任何频率设置为11.3GHz 以下、并且两个频率点之间的切换时间非常短。

初始化寄存器设置
1.设置 DBLBUF_PLL_EN、DBLBUF_CHDIV_EN、DBLBUF_OUTBUF_EN、DBLBUF_OUTMUX_EN = 1
2.设置 DBLR_CAL_EN = 0;INSTCAL_SKIP_ACAL = 0
3.如果需要 VCO 倍频器、请设置 INSTCAL_DBLR_EN = 1、否则将该位设置为0
4.设置 INSTCAL_DLY = T x fosc (以 MHz 为单位)/2^CAL_CLK_DIV、其中 T = 2.5 x CBIASVCO / 0.47µF。 CBIASVCO 是引脚3处的旁路电容
5.将其他寄存器配置为锁定到5.65GHz 而无需任何校准辅助
6.设置 INSTCAL_PLL_NUM = 2^32 x (PLL_NUM / PLL_DEN)
编程
VCC 为 LMX2820上电
8.对所有寄存器进行编程、LMX2820应锁定到5.65GHz
InstCal 校准
9.编程 INSTCAL_EN = 1.
9.5运行索引例程
10.编程 R0 (FCAL = 1)、将开始校准
11、等待100ms
12.编程 R0 (FCAL=0)以完成校准

但当我们将频率更改为高于11.3GHz 时、我们发现两个点:

当我们 按如下所示进行设置时、禁用跟踪滤波器(DBLR_CAL_EN=0)、输出功率将在11GHz 到19GHz 之间的某个频率区域损失、如 pic 所示。

a.对 INSTCAL_PLL_NUM、PLL_N、PLL_NUM 和 PLL_DEN 进行编程(如果其值发生变化)
b.对 R0进行编程(FCAL = 0、DBLR_CAL_EN = 0)以更改 VCO 频率

当我们 按如下所示进行设置时、启用跟踪滤波器(DBLR_CAL_EN=1)、 当我们在极短的时间内切换频点时、频锁指示器 LD 信号将保持为低电平、就像几百微秒一样。

a.对 INSTCAL_PLL_NUM、PLL_N、PLL_NUM 和 PLL_DEN 进行编程(如果其值发生变化)
b.对 R0进行编程(FCAL = 0、DBLR_CAL_EN = 0)以更改 VCO 频率

当我们想在2GHz 至20GHz 之间快速切换频率点时、任何人可以帮助解决该问题吗? 非常感谢。

  • 请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

    大家好、Lucas:

    在步骤3中、您是否设置了  INSTCAL_DBLR_EN = 1?

    在第12步之后、您是否看到 LD 引脚变为高电平? 否则、我们需要对 RESET = 1进行编程以复位 LMX2820。 复位后、重复步骤8至12。

    这是一个经过验证的编程序列。 以下是使用该序列的测试数据。

    2GHz 和20GHz 的频谱。

    20GHz 至2GHz 的锁定时间。

    2GHz 至20GHz 的锁定时间。

  • 请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

    尊敬的 Neol:  

    非常感谢您的回复。 请帮助您更正序列、以便我们可以解决该问题。

    从第1步到第8步、我们将进行如下设置:

    reg_r0 <= 24'h004070;
    reg_r1 <= 24'h0157A0;
    REG_R2 <= 24'h0281F4;
    REG_R3 <= 24'h030041;
    REG_R4 <= 24'h044204;
    REG_R5 <= 24'h050032;
    REG_R6 <= 24'h060A43;
    reg_r7 <= 24'h070000;
    REG_R8 <= 24'h08C802;
    REG_R9 <= 24'h090005;
    REG_R10 <= 24'h0A0000;
    reg_r11 <= 24'h0B0602;
    REG_R12 <= 24'h0C0408;
    REG_R13 <= 24'h0D0038;
    reg_r14 <= 24'h0E3001;
    REG_R15 <= 24'h0F2001;
    REG_R16 <= 24'h10171E;
    REG_R17 <= 24'h1115C0;
    REG_R18 <= 24'h120000;
    reg_r19 <= 24'h132120;
    REG_R20 <= 24'h14272C;
    REG_R21 <= 24'h151C64;
    REG_R22 <= 24'h16E2BF;
    REG_R23 <= 24'h171102;
    REG_R24 <= 24'h180E34;
    REG_R25 <= 24'h190624;
    REG_R26 <= 24'h1A0DB0;
    reg_r27 <= 24'h1B8001;
    REG_R28 <= 24'h1C0639;
    REG_R29 <= 24'h1D318C;
    reg_r30 <= 24'h1EB18C;
    REG_R31 <= 24'h1F0401;
    reg_r32 <= 24'h201401;
    reg_r33 <= 24'h210000;
    reg_r34 <= 24'h220010;
    REG_R35 <= 24'h233100;
    REG_R36 <= 24'h24004B;
    REG_R37 <= 24'h250500;
    REG_R38 <= 24'h260001;
    REG_R39 <= 24'h2786A0;
    reg_r40 <= 24'h280000;
    reg_r41 <= 24'h290000;
    REG_R42 <= 24'h2A0000;
    REG_R43 <= 24'h2B0000;
    REG_R44 <= 24'h2C0000;
    reg_r45 <= 24'h2D0000;
    REG_R46 <= 24'h2E0300;
    reg_r47 <= 24'h2F0300;
    REG_R48 <= 24'h304180;
    REG_R49 <= 24'h310000;
    REG_R50 <= 24'h320080;
    REG_R51 <= 24'h33203F;
    REG_R52 <= 24'h340000;
    REG_R53 <= 24'h350000;
    REG_R54 <= 24'h360000;
    REG_R55 <= 24'h370002;
    REG_R56 <= 24'h380001;
    REG_R57 <= 24'h390001;
    REG_R58 <= 24'h3A0000;
    reg_r59 <= 24'h3B1388;
    reg_r60 <= 24'h3C01F4;
    REG_R61 <= 24'h3D03E8;
    REG_R62 <= 24'h3E0000;
    REG_R63 <= 24'h3FC350;
    reg_r64 <= 24'h400080;
    REG_R65 <= 24'h410000;
    REG_R66 <= 24'h42003F;
    reg_r67 <= 24'h431000;
    REG_R68 <= 24'h440020;
    reg_r69 <= 24'h450011;
    REG_R70 <= 24'h4600FE;
    REG_R71 <= 24'h470000;
    REG_R72 <= 24'h480000;
    reg_r73 <= 24'h490000;
    REG_R74 <= 24'h4A0000;
    REG_R75 <= 24'h4B0000;
    reg_r76 <= 24'h4C0000;
    REG_R77 <= 24'h4D0608;
    reg_r78 <= 24'h4E0011;
    reg_r79 <= 24'h4F002E;
    reg_r80 <= 24'h5001C0;
    reg_r81 <= 24'h510000;
    REG_R82 <= 24'h520000;
    REG_R83 <= 24'h530F00;
    REG_R84 <= 24'h540040;
    REG_R85 <= 24'h550000;
    reg_r86 <= 24'h560040;
    reg_r87 <= 24'h57FF00;
    reg_r88 <= 24'h5803FF;
    reg_r89 <= 24'h590000;
    REG_R90 <= 24'h5A0000;
    reg_r91 <= 24'h5B0000;
    reg_r92 <= 24'h5C0000;
    REG_R93 <= 24'h5D1000;
    reg_r94 <= 24'h5E0000;
    REG_R95 <= 24'h5F0000;
    REG_R96 <= 24'h6017F8;
    reg_r97 <= 24'h610000;
    reg_r98 <= 24'h621C80;
    reg_r99 <= 24'h6319B9;
    reg_r100 <= 24'h640533;
    REG_R101 <= 24'h6503E8;
    reg_r102 <= 24'h660028;
    reg_r103 <= 24'h670014;
    reg_r104 <= 24'h680014;
    REG_R105 <= 24'h69000A;
    reg_r106 <= 24'h6A0000;
    reg_r107 <= 24'h6B0000;
    reg_r108 <= 24'h6C0000;
    reg_r109 <= 24'h6D0000;
    reg_r110 <= 24'h6E001F;
    reg_r111 <= 24'h6F0000;
    reg_r112 <= 24'h70FFFF;
    reg_r113 <= 24'h710000;
    reg_r114 <= 24'h720000;
    reg_r115 <= 24'h730000;
    reg_r116 <= 24'h740000;
    REG_R117 <= 24'h750000;
    reg_r118 <= 24'h760000;
    reg_r119 <= 24'h770000;
    REG_R120 <= 24'h780000;
    reg_r121 <= 24'h790000;
    reg_r122 <= 24'h7A0000;

    从第9步到第12步、我们设置如下:

    SPI_DATA <= 24'h0157A1;
    SPI_DATA <= 24'h6A0400;
    SPI_DATA <= 24'h6B0000;
    SPI_DATA <= 24'h6C0000;
    SPI_DATA <= 24'h6D0000;
    SPI_DATA <= 24'h6A0602;
    SPI_DATA <= 24'h6A0E02;
    SPI_DATA <= 24'h6A0602;
    SPI_DATA <= 24'h6A0603;
    SPI_DATA <= 24'h6A0E03;
    SPI_DATA <= 24'h6A0603;
    SPI_DATA <= 24'h6A0604;
    SPI_DATA <= 24'h6A0E04;
    SPI_DATA <= 24'h6A0604;
    SPI_DATA <= 24'h6A0605;
    SPI_DATA <= 24'h6A0E05;
    SPI_DATA <= 24'h6A0605;
    SPI_DATA <= 24'h6A0606;
    SPI_DATA <= 24'h6A0E06;
    SPI_DATA <= 24'h6A0606;
    SPI_DATA <= 24'h6A0607;
    SPI_DATA <= 24'h6A0E07;
    SPI_DATA <= 24'h6A0607;
    SPI_DATA <= 24'h6A0000;
    SPI_DATA <= 24'h004030;

    SPI_DATA <= 24'h004020;

  • 请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

    大家好、Lucas:

    您的参考时钟频率是多少?

    在步骤1至8中、您是否按照降序对寄存器进行编程? 即从 R122到 R0。