LMK03318: LMK03318 accuracy check

Hi Brian,

The accuracy of the clock output of LMK03318 depends on the input clock, if the input clock is very accurate then you'll get an accurate clock output. Additionally, LMK03318 has configurable load capacitors on the input pins for further adjustment for accuracy.

Best,

Sandra 

Hi Brian,

For some reason i am also not able to upload on this thread either.

I see that on the datasheet of 7M (7M50072001) the stability is +/-25ppm at room temperature but I don't see any comment on stability across temperature for this part.

If they don't observe a frequency output with the required frequency stability customer can use Fine Frequency Margining on SECREF to pull the XTAL by up to +/- 50 ppm on LMK03318. Reference section 10.1.2.1 Fine Frequency Margining of the datasheet. With section 8.4.3 Crystal Input Interface (SEC_REF) that highlights the equation to calculate capacitor values and 8.7 Pullable Crystal Characteristics (SECREF_P, SECREF_N) table highlighting the XTAL characteristics.  

 Also from the datasheet going over the details of load caps and nominal frequencies 

"

The crystal pullability ratio is considered in the case where the XO frequency margining option is enabled. The actual pull range depends on the crystal pullability, as well as on-chip capacitance (Con-chip), device crystal oscillator input capacitance (CXO), PCB stray capacitance (CPCB), and any installed on-board tuning capacitance (CTUNE). Trim sensitivity or pullability (ppm/pF), TS = C1 × 1e6 / [2 × (C0 + CL) 2 ]. If the total external capacitance is less than the crystal CL, the crystal oscillates at a higher frequency than the nominal crystal frequency. If the total external capacitance is higher than CL, the crystal oscillates at a lower frequency than nominal.

"

 Best,

Sandra