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Initial Phasde Control Method of two HMC703s

Question asked by Jiwon.Lee on Sep 1, 2016
Latest reply on Sep 12, 2016 by DonY



I'm trying to synchronize( or have fixed phase offset) the VCO output phase of below two HMC703 at every Power On.

Two HMC703's REF comes from single 100MHz OCXO.

I've tried initial phase control method as written in data sheet.

1) Seed value of each HMC703 : used default value( REG 05H => Default(654321H) )  

2) Autoseed : REG 06H Bit[8] = '1'

3) Triggering : used below two method but the result was same(random phase).

    3-1) Used SPI write TRIGBIT in REG 0EH

    3-2) External hardware trigger pin-6(TRIG) with EXTTRIG_EN


Open Mode Serial Control

REG 01H => 000002H,                REG 02H => 000002H

REG 03H => 00003AH,                REG 04H => F33333H

REG 05H => Default(654321H),  REG 06H => 401D1FH

REG 07H => 104845H,                REG 08H => 0167FFH

REG 09H => 583FFFH,               REG 0AH => 000000H

REG 0BH => 01E071H,               Others => Default


I couldn't get synchronized of fixed phase offset  VCO output with upper settings.

Can you please help what could be the reason ?

Or Is there any application note describing initial phase control ?

Or is there any register writing sequence to control the inital phase ?