DAC38J84: DAC PLL Configurations

Pavan

Intellectual 670 points

Part Number: DAC38J84

I want to use DAC PLL in my application.

My Requirement is

SERDES RATE : 6.25 Gbps

DAC Interpolation : x8

Sampling Rate : 2500 MHz

My Configurations are

DAC Input Clock : 312.5 MHz

DAC Output Clock : 2500 MHz

JESD Clock : 312.5 MHz

SERDES Clock : 6250 MHz

Are My configurations Correct ?? ( (I have doubt regarding SERDES Clock)

I have tried multiple configurations, but I am unable to lock the DAC PLL

Can you help me with the configurations ??

I have tried this

over 4 years ago

0 Pavan over 4 years ago

Intellectual 670 points

Please find the attachment of my configuration file for x8 Interpolation without DAC PLL.

without_PLLL.txt
dac_write 0x0 0x0 dac_write 0x0 0x1 dac_write 0x0 0x218 dac_write 0x1 0x3 dac_write 0x2 0x2082 dac_write 0x3 0xA300 dac_write 0x4 0xF0F0 dac_write 0x5 0xFF07 dac_write 0x6 0xFFFF dac_write 0x7 0x3100 dac_write 0x8 0x0 dac_write 0x9 0x0 dac_write 0xA 0x0 dac_write 0xB 0x0 dac_write 0xC 0x400 dac_write 0xD 0x400 dac_write 0xE 0x400 dac_write 0xF 0x400 dac_write 0x10 0x0 dac_write 0x11 0x0 dac_write 0x12 0x0 dac_write 0x13 0x0 dac_write 0x14 0x0 dac_write 0x15 0x0 dac_write 0x16 0x0 dac_write 0x17 0x0 dac_write 0x18 0x0 dac_write 0x19 0x0 dac_write 0x1A 0x20 dac_write 0x1B 0x0 dac_write 0x1E 0x9999 dac_write 0x1F 0x9980 dac_write 0x20 0x8008 dac_write 0x22 0x1B1B dac_write 0x23 0x1FF dac_write 0x24 0x20 dac_write 0x25 0x4000 dac_write 0x26 0x0 dac_write 0x2D 0x1 dac_write 0x2E 0xFFFF dac_write 0x2F 0x4 dac_write 0x30 0x0 dac_write 0x31 0x1000 dac_write 0x32 0x0 dac_write 0x33 0x0 dac_write 0x34 0x0 dac_write 0x3B 0x1800 dac_write 0x3C 0x228 dac_write 0x3D 0x88 dac_write 0x3E 0x108 dac_write 0x3F 0x0 dac_write 0x46 0x1882 dac_write 0x47 0x1C8 dac_write 0x48 0x3143 dac_write 0x49 0x0 dac_write 0x4A 0xF1E dac_write 0x4B 0xF01 dac_write 0x4C 0x1F03 dac_write 0x4D 0x800 dac_write 0x4E 0xF0F dac_write 0x4F 0x1C61 dac_write 0x50 0x0 dac_write 0x51 0xDC dac_write 0x52 0xFF dac_write 0x53 0x0 dac_write 0x54 0xFC dac_write 0x55 0xFF dac_write 0x56 0x0 dac_write 0x57 0xFF dac_write 0x58 0xFF dac_write 0x59 0x0 dac_write 0x5A 0xFF dac_write 0x5B 0xFF dac_write 0x5C 0x1133 dac_write 0x5E 0x0 dac_write 0x5F 0x3210 dac_write 0x60 0x5764 dac_write 0x61 0x211 dac_write 0x64 0x1 dac_write 0x65 0x1 dac_write 0x66 0x1 dac_write 0x67 0x1 dac_write 0x68 0x7709 dac_write 0x69 0x0 dac_write 0x6A 0x0 dac_write 0x6B 0xBD07 dac_write 0x6C 0x7 dac_write 0x6D 0x90 dac_write 0x6E 0x0 dac_write 0x6F 0x0 dac_write 0x70 0x0 dac_write 0x71 0x0 dac_write 0x72 0x0 dac_write 0x73 0x0 dac_write 0x74 0x0 dac_write 0x75 0x0 dac_write 0x76 0x0 dac_write 0x77 0x0 dac_write 0x78 0x0 dac_write 0x79 0x0 dac_write 0x7A 0x0 dac_write 0x7B 0x0 dac_write 0x7C 0x0 dac_write 0x7D 0x0 dac_write 0x3B 0x1800 dac_write 0x25 0x6000 dac_write 0x3C 0x228 dac_write 0x3C 0x28 dac_write 0x3E 0x128 dac_write 0x4D 0x300 dac_write 0x4D 0x300 dac_write 0x4E 0xF0F dac_write 0x0 0x418

Now to use the DAC PLL and SERDES PLL, I Have added some more configurations to it

0x02 0x2082 #config2
0x1A 0x0000 #config26
0x23 0x0000 #config35
0x25 0x6000 #config37 Div8
0x31 0x6408 #config49
0x32 0x0F00 #config50 Prescalar = 2, M divider = 16
0x33 0x4D84 #config51 pll_VCO_Sel = 0, pll_VCO = 38 ,PLL_VCO_itune = 11,
0x3B 0xF100 #config59 SERDES Clk = Pll Clk, Divide Down value = 16
0x3C 0x82A0 #config60 VRANGE = 1, MPY = 20 (Doubt about MPY for SERDES RATE of 6.25 Gbps)
0x3E 0x0040 #config62 RATE = QUARTER

Please verify these configurations

PLL is not getting locked even with these configurations

Is there any understanding difference ??

Please help me out