DAC38RF82: Pin J5 and sync signal

Tang,

For #1, please follow the steps shown in section 9.1.1, Start-up Sequence. There are several steps involved to get the SYNC to toggle.

For #2,  TRST has an internal pull-up, so if you are floating this signal, the DAC will see this as a logic "1", which may force the part into JTAG test mode. I will look into this more.

Regards,

Jim

Hi Jim,

I really appreciate your support . If you have any other findings of the pin J5, please tell me.

I need your help with another problem. I want to know how to configure the SerDes PLL? I use the model 84111, 2TX, 8X, JESD lane rate 11.25Gbps, DAC PLL output 9G.

The relationship as follow:

DAC PLL output 9G / 4 / SERDES_REFCLK_DIV (4) = SERDES PLL REFCLK(562.5MHz)

SERDES PLL REFCLK(562.5MHz) x MPY(0x43C,5) = SERDES PLL OUTPUT (2.8125GHz)= 0.25 x JESD LANE RATE (11.25Gbps)

8MHz < SERDES PLL REFCLK / BWSCALE(Low loop bandwidth 21 ) < 30MHz

Is this correct?

So the SerDes PLL register configuration :

Address      Data

0x43B          0x9800

0x43C          0x9051

0x43D          0x0088

0x43E          0x0909

0x43F          0x0000

The SerDes PLL goes out of lock and the register( 0x05[2:1] ) is always "11".

I also find that the multiply factor MPY is different between datasheet( in table 4 of Page 27) and the software DAC38RF8x EVM GUI V3P0

Thanks,

Tang

Tang,

The values should be as follows:

Address      Data

0x43B          0x9802

0x43C          0x8029

0x43D          0x0088

0x43E          0x0929

0x43F          0x0000

What frequency is your DAC PLL reference clock?

Regards,

Jim

Jim,

 DAC PLL reference clock  is 562.5MHz. The M parameter is set to 4 and the N parameter is set to 1. Does this have any impact on SerDes PLL?

Regards,

Tang

Hi Jim,

I have used the SerDes PLL registers configuration that you have provided, but the SerDes PLL is still unlocked. Do you have any other suggestions for solving the problems? Are there any other registers that may have an impact on SerDes PLL?

What frequency is your SYSREF clock when using the model 84111?

Thanks,

Tang