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LMK04828BEVM: PLL not locked

6354578
Prodigy 30 points
Part Number: LMK04828BEVM


Hello,

I have an issue with LMK04828B.

once in 10-20 power cycels , i have a PLL not locked , register 0x183 bit 1 = 0.

I suspect the loop filter parameter , can you direct me how to apply the right values.

image.png

 

Thank you,

Amir.

  • 0
    TI__Mastermind 34270 points

    Can you provide the register programming and the frequency provided to PLL2? Without knowing how the PLL is configured, it is not possible for us to say whether the loop filter components are chosen correctly.

  • 0 in reply to Derek Payne
    Prodigy 30 points

    Hi,

    This is the configuration:

    R0 (INIT) 0x000090
    R0 0x000010
    R2 0x000200
    R3 0x000306
    R4 0x0004D0
    R5 0x00055B
    R6 0x000600
    R12 0x000C51
    R13 0x000D04
    R256 0x01000C
    R257 0x010155
    R258 0x010255
    R259 0x010301
    R260 0x010402
    R261 0x010500
    R262 0x010670
    R263 0x010711
    R264 0x01080C
    R265 0x010955
    R266 0x010A55
    R267 0x010B00
    R268 0x010C02
    R269 0x010D00
    R270 0x010EF0
    R271 0x010F10
    R272 0x01100F
    R273 0x011155
    R274 0x011255
    R275 0x011301
    R276 0x011402
    R277 0x011500
    R278 0x011670
    R279 0x011711
    R280 0x01180C
    R281 0x011955
    R282 0x011A55
    R283 0x011B00
    R284 0x011C02
    R285 0x011D00
    R286 0x011E71
    R287 0x011F35
    R288 0x01200C
    R289 0x012155
    R290 0x012255
    R291 0x012300
    R292 0x012402
    R293 0x012500
    R294 0x012670
    R295 0x012755
    R296 0x01280C
    R297 0x012955
    R298 0x012A55
    R299 0x012B00
    R300 0x012C02
    R301 0x012D00
    R302 0x012EF0
    R303 0x012F50
    R304 0x01300C
    R305 0x013155
    R306 0x013255
    R307 0x013300
    R308 0x013402
    R309 0x013500
    R310 0x013671
    R311 0x013735
    R312 0x013825
    R313 0x013900
    R314 0x013A00
    R315 0x013B01
    R316 0x013C00
    R317 0x013D08
    R318 0x013E03
    R319 0x013F06
    R320 0x014005
    R321 0x014100
    R322 0x014200
    R323 0x014311
    R324 0x0144DD
    R325 0x01457F
    R326 0x014612
    R327 0x01471A
    R328 0x014802
    R329 0x014942
    R330 0x014A02
    R331 0x014B16
    R332 0x014C00
    R333 0x014D00
    R334 0x014EC0
    R335 0x014F7F
    R336 0x015003
    R337 0x015102
    R338 0x015200
    R339 0x015300
    R340 0x015401
    R341 0x015500
    R342 0x015601
    R343 0x015700
    R344 0x015801
    R345 0x015900
    R346 0x015A10
    R347 0x015BD1
    R348 0x015C20
    R349 0x015D00
    R350 0x015E00
    R351 0x015F0B
    R352 0x016000
    R353 0x016108
    R354 0x016224
    R355 0x016300
    R356 0x016400
    R357 0x01654B
    R369 0x0171AA
    R370 0x017202
    R380 0x017C15
    R381 0x017D33
    R358 0x016600
    R359 0x016700
    R360 0x01684B
    R361 0x016959
    R362 0x016A20
    R363 0x016B00
    R364 0x016C00
    R365 0x016D00
    R366 0x016E13
    R371 0x017300
    R8189 0x1FFD00
    R8190 0x1FFE00
    R8191 0x1FFF53

    Thanks,

    Amir.

  • 0 in reply to 6354578
    Prodigy 30 points

    Hello , Any updates?

  • 0 in reply to 6354578
    TI__Genius 12200 points

    Hi Amir,

    Thank you for your patience. Can you try implementing the following loop filters for both PLL1 (first picture) and PLL2 (second picture)?

    Thanks,

    Michael

  • 0 in reply to Michael Srinivasan
    Prodigy 30 points

    HI Michael,

    I will try these loop filters ASAP and update.

    Also , can you please elaborate if my current loop filters (see above schematics) can cause such behavior of PLL not lock once in 10-20 power up?

    Please advice,

    Thank you,

    Amir.

  • 0 in reply to 6354578
    TI__Genius 12200 points

    Hi Amir,

    The filter you have instantiated for PLL2 has a slightly smaller BW than we typically recommend (yours is about 180kHz, and we recommend closer to 300kHz for optimizing jitter. This could result in the occasional loss of lock that you are seeing.

    Thanks,

    Michael