JAJSDF7A January 2017 – May 2017 LMK61E0M
PRODUCTION DATA.
The LMK61E0 features a fully integrated loop filter for the PLL and supports programmable loop bandwidth from 100 kHz to 1 MHz. The loop filter components, R2, C1, R3, C3, can be configured by programming R36, R37, R38 and R39 respectively. The LMK61E0 features a fixed value of C2 of 10 nF. When PLL is configured in the fractional mode, R35[2] should be set to 1. When reference doubler is disabled for integer mode PLL, R35[2] should be set to 0 and R38[6:0] should be set to 0x00. When reference doubler is enabled for integer mode PLL, R35[2] should be set to 1 and R38 and R39 are written with the appropriate values. Figure 5 shows the loop filter structure of the PLL. It is important to set the PLL to best possible bandwidth to minimize output jitter.