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LMX2615-SP: PLL lock fail in low temperature

David Park
Expert 6560 points
Part Number: LMX2615-SP
Other Parts Discussed in Thread: DAC39RF10, ADC12DJ3200

Tool/software:

Hi,

Customer is using LMX2615 for DAC39RF10 and ADC12DJ3200.

output clock is 8388.608MHz for DAC and 2097.152MHz for ADC.

Under low temperature around 6~8C, there is below issue.

1. Leakage at +-2MHz from center frequency(3.55GHz) of DAC

2. with #1 status, after supply off/on, LMX2615 PLL lock fail

Do you have any similar issue or any guidance?

Thanks.

  • +1
    TI__Guru** 104130 points

    Hi David,

    Could you provide the configuration like below?

  • 0 in reply to Noel Fung
    TI__Expert 6560 points

    Hi Noel,

    Please find the attached setting table.

    Fullscreen LMX2615_register_setting.txt Download 
    address value
0072 026F
0071 0000
0070 0000
006F 0000
006E 0000
006D 0000
006C 00F1
006B 0000
006A 0007
0069 4440
0068 0000
0067 0000
0066 0000
0065 0000
0064 0000
0063 0000
0062 0000
0061 0000
0060 0000
005F 0000
005E 0000
005D 0000
005C 0000
005B 0000
005A 0000
0059 0000
0058 8000
0057 0000
0056 0000
0055 0000
0054 0000
0053 0000
0052 0000
0051 0000
0050 0000
004F 0000
004E 0064
004D 0000
004C 000C
004B 0840
004A 0000
0049 003F
0048 0000
0047 0020
0046 C350
0045 0000
0044 03E8
0043 0000
0042 01F4
0041 0000
0040 1388
003F 0000
003E 0322
003D 00A8
003C 1388
003B 0001
003A 8001
0039 0020
0038 0000
0037 0000
0036 0000
0035 0000
0034 0420
0033 0080
0032 0000
0031 4180
0030 0300
002F 0300
002E 07FC
002D C8D8
002C 1823
002B 0000
002A 0000
0029 0000
0028 0000
0027 0001
0026 0000
0025 8304
0024 0040
0023 0004
0022 0000
0021 1E21
0020 0393
001F 43EC
001E 318C
001D 318C
001C 0488
001B 0002
001A 0DB0
0019 0624
0018 071A
0017 007C
0016 0001
0015 0401
0014 C848
0013 27B7
0012 0064
0011 012C
0010 0080
000F 064F
000E 1E70
000D 4000
000C 5002
000B 0018
000A 10D8
0009 1604
0008 2000
0007 00B2
0006 7802
0005 03E8
0004 0E43
0003 0642
0002 0500
0001 080A
0000 211C

  • 0 in reply to David Park
    TI__Guru** 104130 points

    Hi David,

    I tried two boards with your configuration, assume reference clock frequency is 131.072MHz, I don't see the problem. The device remains lock at 0C, -10C or -40C without reprogram.