AnsweredAssumed Answered

AD9523 PLL1 doesn't lock

Question asked by vietht on Mar 5, 2018
Latest reply on Mar 5, 2018 by vietht

Hello,

I'm using AD9523 for my project. I'm able to use PLL2 only and bypass PLL1 before, now i'm trying to using PLL1 to control the external VCXO to increase it's accuracy.

I'm using REF A in CMOS 3.3V as reference clock for PLL1, but I can't see the PLL1 locked detect in status register 0x22C although REF A status is setted. Can anyone help me, its very urgent.

Here's my regiter dump:

0x000=0x80
0x004=0x01
0x010=0x00
0x011=0x00
0x012=0x00
0x013=0x00
0x014=0x00
0x015=0x00
0x016=0x04
0x017=0x00
0x018=0x04
0x019=0x1f
0x01a=0x0a
0x01b=0x04
0x01c=0x08
0x01d=0x03
0x0f0=0x0c
0x0f1=0x06
0x0f2=0x13
0x0f3=0x02
0x0f4=0x00
0x0f5=0x12
0x0f6=0x00
0x0f7=0x01
0x190=0x02
0x191=0x07
0x192=0x00
0x193=0x03
0x194=0x04
0x195=0x00
0x196=0x20
0x197=0x00
0x198=0x00
0x199=0x01
0x19a=0x04
0x19b=0x00
0x19c=0x02
0x19d=0x04
0x19e=0x00
0x19f=0x20
0x1a0=0x00
0x1a1=0x00
0x1a2=0x20
0x1a3=0x00
0x1a4=0x00
0x1a5=0x20
0x1a6=0x00
0x1a7=0x00
0x1a8=0x20
0x1a9=0x00
0x1aa=0x00
0x1ab=0x20
0x1ac=0x00
0x1ad=0x00
0x1ae=0x03
0x1af=0x04
0x1b0=0x00
0x1b1=0x20
0x1b2=0x00
0x1b3=0x00
0x1b4=0x08
0x1b5=0x27
0x1b6=0x00
0x1b7=0x08
0x1b8=0x27
0x1b9=0x00
0x1ba=0x00
0x1bb=0x80

0x22c=0xe6

0x22d=0x00

0x230=0x02
0x231=0x03
0x232=0x00
0x233=0x00

Here's my schematic

Here's my REF A CMOS 3.3 waveform

Here's my VCXO waveform

Here's my ZD_IN diff waveform

Nothing in PLL1_OUT

Thanks alot,

Outcomes