PowerWise® Design University

Fractional PLLs

What are the theoretical advantages of Fractional N PLLs over Integer N PLLs? 1) phase noise, 2) reference spurs, 3) Switching time (lock time)
1, 2
1, 3
2, 3
all of the above

What are the three different types of fractional compensation methods?
Sigma Delta, current, time delay
Sigma delta, voltage, time delay
Current, time delay, noise
Current, time delay, voltage

What is the recommended order of the loop filter if the order of the delta sigma modulator is 3?
3
4
5
None of the above

Suppose I have a 3rd order delta-sigma PLL and I want an N value of 900.2. What values will the PLL divider alternate between?
a) 900 and 901
b) 898, 899, 900, and 901
c) 896, 897, 898, 899, 900, 901, 902, and 903
d) 892, 893, 894, 895, 896, 897, 898, 899, 900, 901, 902, 903, 904, 905, 906, and 907