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Question about LTM8024,LTM4676A and LTM4622 and request a schematic review


My customer is using LTM8024,LTM4676A and LTM4622 in their product.

And they want to get your review about their schematic and ask some questions about using above components.

Please refer their schematic & questions and let me know your opinions.

Q1) They want to synchronize switching frequency as external clock at LTM4676A (or LTM4677).

      It means that they wnat to configure as a sync slave.

     For this as your datatsheet P52, they need a use of a register setting only.

    Do you have any other method to configure using pin strap only ? (without any register setting)

Q2) At LTM8024, would you let me know the phase of Ch. 1 & Ch 2?

       Do both channels a switching at same phase?

R1) Would you conform their schematic ?

     (I attache a pdf file in thie editor. If you have any issues to get schematic in this editor, please let me know your e-mail.)




  • Hi Se-woong, 

    For the LTM4622 schematic, please change the FREQ pin resistor (R51) to 324k for 2MHz instead (to use switching frequency recommended for 3.3Vout). Also, if you have room please add optional footprint for a feed-forward capacitor between each FB and Vout for optional phase margin boost which may be helpful depending on the actual output capacitance for your capacitors at bias. I can only comment for the LTM4622, please wait for other comments regarding the other parts.


  • Hello Se-woong,

    Schematic looks good and please open the R149 and remain R121 there. By doing this, LTM4676A will follow the clock signal from SYNC pin and works as Sync-Slave. The internal register MFR_CONFIG_ALL[4] will automatically updated to disable the SYNC OUT.

    Please see page 49 , Table 4 and the explanation at the bottom of the page regarding the Sync_Slave Setting.  

    In factory default setting, the resistor setting on the configuration pin such as VOUT_CFG, VOUT_TRIM and FSW_PH pin will be all acknowledged.