PLL2 is not locking

Question

Hello, 
 I am working on AD9523-1 customized board. in this new board, I'm having issue i.e. PLL2 is not getting locked. inputs that we are providing are REF A is 100 MHz, REF B is 10 MHz and VCXO input is 100 MHz. and the responses I'm getting are 
 at 0x22C - 0xE9, at 0x22D - 0x04, at 0x230 - 0x00, at 0x231 - 0x01, at 0x232 - 0x0D. and register map file giving to AD9523 is as follows:

Fullscreen 
 Ref_A_Ref_Bconfiguration.txt 
 Download 
 
 "AD9523 Regmap File"
"Rev.","1.0"
""
"Addr(Hex)","Value(Bin)","Value(Hex)"
"0000","10000001","81"
"0002","00000000","00"
"0003","00000000","00"
"0004","00000000","00"
"0005","00000000","00"
"0006","00000000","00"
"0010","00000001","01"
"0011","00000000","00"
"0012","00000100","04"
"0013","00000000","00"
"0014","00000001","01"
"0015","00000000","00"
"0016","00101000","28"
"0017","00000000","00"
"0018","00001100","0C"
"0019","00011111","1F"
"001A","00010010","12"
"001B","00010110","16"
"001C","10010000","90"
"001D","00000000","00"
"001E","00000000","00"
"001F","00000000","00"
"0020","00000000","00"
"00F0","00000111","07"
"00F1","10000111","87"
"00F2","00010011","13"
"00F3","00000010","02"
"00F4","01000000","40"
"00F5","00000000","00"
"00F6","00000000","00"
"00F7","00000001","01"
"00F8","00000000","00"
"00F9","00000000","00"
"00FA","00000000","00"
"0190","01110011","73"
"0191","00001001","09"
"0192","00000100","04"
"0193","00100000","20"
"0194","00011111","1F"
"0195","00000100","04"
"0196","01001000","48"
"0197","01100011","63"
"0198","00000000","00"
"0199","01110110","76"
"019A","00011111","1F"
"019B","00000100","04"
"019C","01001000","48"
"019D","01100011","63"
"019E","00000000","00"
"019F","00100000","20"
"01A0","00011111","1F"
"01A1","00000100","04"
"01A2","00100000","20"
"01A3","00011111","1F"
"01A4","00000100","04"
"01A5","00100000","20"
"01A6","00011111","1F"
"01A7","00000100","04"
"01A8","01100110","66"
"01A9","00001001","09"
"01AA","00000100","04"
"01AB","01001001","49"
"01AC","01100011","63"
"01AD","00000000","00"
"01AE","01001001","49"
"01AF","01100011","63"
"01B0","00000000","00"
"01B1","01101000","68"
"01B2","00001001","09"
"01B3","00000100","04"
"01B4","01101000","68"
"01B5","00001001","09"
"01B6","00000100","04"
"01B7","01010110","56"
"01B8","00001001","09"
"01B9","00000000","00"
"01BA","00000000","00"
"01BB","00000000","00"
"022C","00000000","00"
"022D","00000000","00"
"022E","00000000","00"
"022F","00000000","00"
"0230","00000000","00"
"0231","00000001","01"
"0232","00001101","0D"
"0233","00000000","00"
"0234","00000001","01"
"0A00","00000000","00"
"0A01","00000000","00"
"0A02","00000000","00"
"0A03","00000010","02"
"0A04","00000000","00"
"0A05","00000100","04"
"0A06","00001110","0E"
"0A07","00000000","00"
"0A08","00010000","10"
"0A09","00001110","0E"
"0A0A","00000000","00"
"0A0B","11110000","F0"
"0A0C","00101011","2B"
"0A0D","00000001","01"
"0A0E","10010000","90"
"0A0F","00000001","01"
"0A10","00000001","01"
"0A11","11100000","E0"
"0A12","00000011","03"
"0A13","00000010","02"
"0A14","00110000","30"
"0A15","10000000","80"
"0A16","11111111","FF"
"0B00","00000000","00"
"0B01","00000000","00"
"0B02","00000000","00"
"0B03","00000000","00"

kindly help me in resolving this issue.

pminc48 · Accepted Answer

Hi, 
 you say you want to configure the AD9523-1 to work with a VCXO=100MHz. Yet, the file you sent shows a VCXO=122.88MHz. 
 
 Then the PLL2 was not configured correctly because it has a value lower than the min PLL2 VCO specification.

Please tell me what output frequencies you need and I'll create a configuration for you. I already responded to you here: 
 RE: How to set output frequency as 156.25 MHz ? 
 that the AD9523-1 cannot create 156.25MHz clocks. 
 Petre)

pminc48 · Answer

Hi, 
 I'm sorry, but you need to send me the stp file you created in order to extract the register values. I cannot upload this file to see what is going on. 
 Petre

pminc48 · Answer

HI, When I converted your file to a file with a stp extension, and then I loaded it into the AD9523-1 evaluation software, I was given an error. I compared your file with a stp file I have, and they are different. I attach my file, which I used for our discussion. Compared it against yours. How did you obtain your file? Fullscreen 2630.AD9523_1_setup.stp.txt Download ;Header contains information about the setup file and revision

Product = AD9523-1 FileVersion = 1.0 DecimalSeparator=. ;Used for internationalization

&h0,&b00000001 ;01 Hex, 001 Dec &h2,&b00000000 ;00 Hex, 000 Dec &h3,&b00000000 ;00 Hex, 000 Dec &h4,&b00000000 ;00 Hex, 000 Dec &h5,&b00000000 ;00 Hex, 000 Dec &h6,&b00000000 ;00 Hex, 000 Dec &h10,&b00000001 ;01 Hex, 001 Dec &h11,&b00000000 ;00 Hex, 000 Dec &h12,&b00000100 ;04 Hex, 004 Dec &h13,&b00000000 ;00 Hex, 000 Dec &h14,&b00000001 ;01 Hex, 001 Dec &h15,&b00000000 ;00 Hex, 000 Dec &h16,&b00101000 ;28 Hex, 040 Dec &h17,&b00000000 ;00 Hex, 000 Dec &h18,&b00001100 ;0C Hex, 012 Dec &h19,&b00011111 ;1F Hex, 031 Dec &h1A,&b00010010 ;12 Hex, 018 Dec &h1B,&b00010110 ;16 Hex, 022 Dec &h1C,&b10010000 ;90 Hex, 144 Dec &h1D,&b00000000 ;00 Hex, 000 Dec &h1E,&b00000000 ;00 Hex, 000 Dec &h1F,&b00000000 ;00 Hex, 000 Dec &h20,&b00000000 ;00 Hex, 000 Dec &hF0,&b00000111 ;07 Hex, 007 Dec &hF1,&b10000111 ;87 Hex, 135 Dec &hF2,&b00010011 ;13 Hex, 019 Dec &hF3,&b00000010 ;02 Hex, 002 Dec &hF4,&b01000000 ;40 Hex, 064 Dec &hF5,&b00000000 ;00 Hex, 000 Dec &hF6,&b00000000 ;00 Hex, 000 Dec &hF7,&b00000001 ;01 Hex, 001 Dec &hF8,&b00000000 ;00 Hex, 000 Dec &hF9,&b00000000 ;00 Hex, 000 Dec &hFA,&b00000000 ;00 Hex, 000 Dec &h190,&b01110011 ;73 Hex, 115 Dec &h191,&b00001001 ;09 Hex, 009 Dec &h192,&b00000100 ;04 Hex, 004 Dec &h193,&b00100000 ;20 Hex, 032 Dec &h194,&b00011111 ;1F Hex, 031 Dec &h195,&b00000100 ;04 Hex, 004 Dec &h196,&b01001000 ;48 Hex, 072 Dec &h197,&b00001001 ;09 Hex, 009 Dec &h198,&b00000000 ;00 Hex, 000 Dec &h199,&b01110110 ;76 Hex, 118 Dec &h19A,&b00011111 ;1F Hex, 031 Dec &h19B,&b00000100 ;04 Hex, 004 Dec &h19C,&b01001000 ;48 Hex, 072 Dec &h19D,&b00001001 ;09 Hex, 009 Dec &h19E,&b00000000 ;00 Hex, 000 Dec &h19F,&b00100000 ;20 Hex, 032 Dec &h1A0,&b00011111 ;1F Hex, 031 Dec &h1A1,&b00000100 ;04 Hex, 004 Dec &h1A2,&b00100000 ;20 Hex, 032 Dec &h1A3,&b00011111 ;1F Hex, 031 Dec &h1A4,&b00000100 ;04 Hex, 004 Dec &h1A5,&b00100000 ;20 Hex, 032 Dec &h1A6,&b00011111 ;1F Hex, 031 Dec &h1A7,&b00000100 ;04 Hex, 004 Dec &h1A8,&b01100110 ;66 Hex, 102 Dec &h1A9,&b00001001 ;09 Hex, 009 Dec &h1AA,&b00000100 ;04 Hex, 004 Dec &h1AB,&b01001001 ;49 Hex, 073 Dec &h1AC,&b00001001 ;09 Hex, 009 Dec &h1AD,&b00000000 ;00 Hex, 000 Dec &h1AE,&b01001001 ;49 Hex, 073 Dec &h1AF,&b00001001 ;09 Hex, 009 Dec &h1B0,&b00000000 ;00 Hex, 000 Dec &h1B1,&b01101000 ;68 Hex, 104 Dec &h1B2,&b00001001 ;09 Hex, 009 Dec &h1B3,&b00000100 ;04 Hex, 004 Dec &h1B4,&b01101000 ;68 Hex, 104 Dec &h1B5,&b00001001 ;09 Hex, 009 Dec &h1B6,&b00000100 ;04 Hex, 004 Dec &h1B7,&b01010110 ;56 Hex, 086 Dec &h1B8,&b00001001 ;09 Hex, 009 Dec &h1B9,&b00000000 ;00 Hex, 000 Dec &h1BA,&b00000000 ;00 Hex, 000 Dec &h1BB,&b00000000 ;00 Hex, 000 Dec &h22C,&b00000000 ;00 Hex, 000 Dec &h22D,&b00000000 ;00 Hex, 000 Dec &h22E,&b00000000 ;00 Hex, 000 Dec &h22F,&b00000000 ;00 Hex, 000 Dec &h230,&b00000000 ;00 Hex, 000 Dec &h231,&b00000001 ;01 Hex, 001 Dec &h232,&b00000000 ;00 Hex, 000 Dec &h233,&b00000000 ;00 Hex, 000 Dec &h234,&b00000001 ;01 Hex, 001 Dec &hA00,&b00000000 ;00 Hex, 000 Dec &hA01,&b00000000 ;00 Hex, 000 Dec &hA02,&b00000000 ;00 Hex, 000 Dec &hA03,&b00000010 ;02 Hex, 002 Dec &hA04,&b00000000 ;00 Hex, 000 Dec &hA05,&b00000100 ;04 Hex, 004 Dec &hA06,&b00001110 ;0E Hex, 014 Dec &hA07,&b00000000 ;00 Hex, 000 Dec &hA08,&b00010000 ;10 Hex, 016 Dec &hA09,&b00001110 ;0E Hex, 014 Dec &hA0A,&b00000000 ;00 Hex, 000 Dec &hA0B,&b11110000 ;F0 Hex, 240 Dec &hA0C,&b00101011 ;2B Hex, 043 Dec &hA0D,&b00000001 ;01 Hex, 001 Dec &hA0E,&b10010000 ;90 Hex, 144 Dec &hA0F,&b00000001 ;01 Hex, 001 Dec &hA10,&b00000001 ;01 Hex, 001 Dec &hA11,&b11100000 ;E0 Hex, 224 Dec &hA12,&b00000011 ;03 Hex, 003 Dec &hA13,&b00000010 ;02 Hex, 002 Dec &hA14,&b00110000 ;30 Hex, 048 Dec &hA15,&b10000000 ;80 Hex, 128 Dec &hA16,&b11111111 ;FF Hex, 255 Dec &hB00,&b00000000 ;00 Hex, 000 Dec &hB01,&b00000000 ;00 Hex, 000 Dec &hB02,&b00000000 ;00 Hex, 000 Dec &hB03,&b00000000 ;00 Hex, 000 Dec PortA=&h1E ;Bit0=USBStatus, Bit1=CSB, Bit2=ResetB, Bit3=SyncB, Bit4=PDB, Bit5=RefSel AutoSendUpdate=1 ;AutoIOUpdate Setting REF_A = 10.0000 REF_B = 10.0000 REF_TEST = 10.0000 VCXO = 100.0000 Petre

pminc48 · Answer

Hi, 
 Thanks for the tip. I was able to load the register values you sent. Next time, please save the configuration from File, Save Setup function. and send it to me. 
 These are my comments about the configuration and schematic (which is not very clear. If you could send a more accurate, photo, it would be better): 
 - the PLL2 charge pump current is too small at 24.5 uA. I recommend to bring that current up to at least 882.0 uA. Disable the anti-backlash period. 
 - If REFA=100 MHz, then set the REFA=40. 
 - VCXO is set for the negative SE input, but the schematic shows the OSC_IN pin ac coupled to a VCXO pin. You need to take that pin and ac couple it to ground. Measure the clock at OSC_IN\ pin to verify it is a 3.3V CMOS clock. 
 Let's see if you can get the PLL2 to lock. I cannot verify the configuration because I do not have a board with VCXO=100MHz. I have one with VCXO=122.88MHz, and your configuration makes the PLL2 VCO to be out of range. 
 
 Petre

pminc48 · Answer

Hi, 
 
 Let's suppose the Crystek OUT pin 3 corresponds to pin 4 of Y2 on your schematic: 
 - R23=0hm should be populated. This means the VCXO output goes to pin 10, OSC_IN\. So in the eval software, you should check the box about Enable VCXO Negative SE Input Receiver. 
 - do not install R26=50ohm because 50ohm is a bad load for a 3.3V CMOS clock 
 - install C19=0.1uF, R17 with a 0ohm resistor, R15 with a 0ohm resistor, so pin 9, OSC_IN is connected to GND through a capacitor. 
 
 Petre

pminc48 · Answer

Hi, 
 
 I do believe that at this point, you should change your board with a different one and see if the behavior repeats. 
 The readback registers 0x22C and 0x22D are the registers that the AD9523-1 has to provide status. 
 Petre

pminc48 · Answer

Hi, 
 take the AD9523-1 from board 1 and exchange it with an AD9523-1 from the other boards. See if the boards with exchanged chips start to function. 
 Petre

pminc48 · Answer

HI, 
 if you want, you mat start a failure analysis process for this AD9523-1 that you moved from board 2 to board 1 and it continues to not work. Contact your ADI representative to initiate it. 
 Could you please replace this AD9523-1 with others that you have and see if the board continues to not function? 
 
 Petre

pminc48 · Answer

HI, 
 
 so you say that on board 1, you placed brand new AD9523-1 ICs and they locked only PLL2, while PLL1 did not. 
 In my view, the reference clock is beyond specification limit. Try changing the source of that clock and see if the AD9523-1 ICs lock. 
 Petre

pminc48 · Answer

Hi, 
 I told you already what I would do if I was in your situation: the reference clock is beyond specification limit. Try changing the source of that clock and see if the AD9523-1 ICs lock. 
 Petre

pminc48 · Answer

Hi, 
 
 Please ask in your company someone with more experience to help you. Clearly, exchanging emails every day with me about your boards (I counted 37 until today) does not seem to make much progress. And now I'm confused about what is going on, on what board, with what chip, with what PLL, etc. 
 
 Petre

pminc48 · Answer

Hi, 
 
 Could you please ask your ADI sales representative to ask a FAE to work with you on this issue in your lab. 
 
 Petre

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PLL2 is not locking